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Bonsor DA, Simanshu DK. RAS and SHOC2 Roles in RAF Activation and Therapeutic Considerations. ANNUAL REVIEW OF CANCER BIOLOGY 2024; 8:97-113. [PMID: 38882927 PMCID: PMC11178279 DOI: 10.1146/annurev-cancerbio-062822-030450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2024]
Abstract
Mutations in RAS proteins play a pivotal role in the development of human cancers, driving persistent RAF activation and deregulating the Mitogen-Activated Protein Kinase (MAPK) signaling pathway. While progress has been made in targeting specific oncogenic RAS proteins, effective drug-based therapies for the majority of RAS mutations remain limited. Recent investigations on RAS-RAF complexes and the SHOC2-MRAS-PP1C holoenzyme complex have provided crucial insights into the structural and functional aspects of RAF activation within the MAPK signaling pathway. Moreover, these studies have also unveiled new blueprints for developing inhibitors allowing us to think beyond the current RAS and MEK inhibitors. In this review, we explore the roles of RAS and SHOC2 in activating RAF and discuss potential therapeutic strategies to target these proteins. A comprehensive understanding of the molecular interactions involved in RAF activation and their therapeutic implications holds the potential to drive innovative approaches in combating RAS/RAF-driven cancers.
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Affiliation(s)
- Daniel A. Bonsor
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Dhirendra K. Simanshu
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
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2
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Liu NF, Enomoto M, Marshall CB, Ikura M. Reconstitution and characterization of BRAF in complex with 14-3-3 and KRAS4B on nanodiscs. Protein Sci 2024; 33:e5016. [PMID: 38747381 PMCID: PMC11094772 DOI: 10.1002/pro.5016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 04/17/2024] [Accepted: 04/25/2024] [Indexed: 05/19/2024]
Abstract
RAF kinases are key components of the RAS-MAPK signaling pathway, which drives cell growth and is frequently overactivated in cancer. Upstream signaling activates the small GTPase RAS, which recruits RAF to the cell membrane, driving a transition of the latter from an auto-inhibited monomeric conformation to an active dimer. Despite recent progress, mechanistic details underlying RAF activation remain unclear, particularly the role of RAS and the membrane in mediating this conformational rearrangement of RAF together with 14-3-3 to permit RAF kinase domain dimerization. Here, we reconstituted an active complex of dimeric BRAF, a 14-3-3 dimer and two KRAS4B on a nanodisc bilayer and verified that its assembly is GTP-dependent. Biolayer interferometry (BLI) was used to compare the binding affinities of monomeric versus dimeric full-length BRAF:14-3-3 complexes for KRAS4B-conjugated nanodiscs (RAS-ND) and to investigate the effects of membrane lipid composition and spatial density of KRAS4B on binding. 1,2-Dioleoyl-sn-glycero-3-phospho-L-serine (DOPS) and higher KRAS4B density enhanced the interaction of BRAF:14-3-3 with RAS-ND to different degrees depending on BRAF oligomeric state. We utilized our reconstituted system to dissect the effects of KRAS4B and the membrane on the kinase activity of monomeric and dimeric BRAF:14-3-3 complexes, finding that KRAS4B or nanodiscs alone were insufficient to stimulate activity, whereas RAS-ND increased activity of both states of BRAF. The reconstituted assembly of full-length BRAF with 14-3-3 and KRAS on a cell-free, defined lipid bilayer offers a more holistic biophysical perspective to probe regulation of this multimeric signaling complex at the membrane surface.
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Affiliation(s)
- Ningdi F. Liu
- Princess Margaret Cancer CentreUniversity Health NetworkTorontoOntarioCanada
- Department of Medical BiophysicsUniversity of TorontoTorontoOntarioCanada
| | - Masahiro Enomoto
- Princess Margaret Cancer CentreUniversity Health NetworkTorontoOntarioCanada
| | | | - Mitsuhiko Ikura
- Princess Margaret Cancer CentreUniversity Health NetworkTorontoOntarioCanada
- Department of Medical BiophysicsUniversity of TorontoTorontoOntarioCanada
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3
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Shrestha R, Carpenter TS, Van QN, Agamasu C, Tonelli M, Aydin F, Chen D, Gulten G, Glosli JN, López CA, Oppelstrup T, Neale C, Gnanakaran S, Gillette WK, Ingólfsson HI, Lightstone FC, Stephen AG, Streitz FH, Nissley DV, Turbyville TJ. Membrane lipids drive formation of KRAS4b-RAF1 RBDCRD nanoclusters on the membrane. Commun Biol 2024; 7:242. [PMID: 38418613 PMCID: PMC10902389 DOI: 10.1038/s42003-024-05916-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 02/14/2024] [Indexed: 03/02/2024] Open
Abstract
The oncogene RAS, extensively studied for decades, presents persistent gaps in understanding, hindering the development of effective therapeutic strategies due to a lack of precise details on how RAS initiates MAPK signaling with RAF effector proteins at the plasma membrane. Recent advances in X-ray crystallography, cryo-EM, and super-resolution fluorescence microscopy offer structural and spatial insights, yet the molecular mechanisms involving protein-protein and protein-lipid interactions in RAS-mediated signaling require further characterization. This study utilizes single-molecule experimental techniques, nuclear magnetic resonance spectroscopy, and the computational Machine-Learned Modeling Infrastructure (MuMMI) to examine KRAS4b and RAF1 on a biologically relevant lipid bilayer. MuMMI captures long-timescale events while preserving detailed atomic descriptions, providing testable models for experimental validation. Both in vitro and computational studies reveal that RBDCRD binding alters KRAS lateral diffusion on the lipid bilayer, increasing cluster size and decreasing diffusion. RAS and membrane binding cause hydrophobic residues in the CRD region to penetrate the bilayer, stabilizing complexes through β-strand elongation. These cooperative interactions among lipids, KRAS4b, and RAF1 are proposed as essential for forming nanoclusters, potentially a critical step in MAP kinase signal activation.
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Affiliation(s)
- Rebika Shrestha
- RAS Initiative, The Cancer Research Technology Program, Frederick National Laboratory, Frederick, MD, 21701, USA
| | - Timothy S Carpenter
- Physical and Life Sciences (PLS) Directorate, Lawrence Livermore National Laboratory, Livermore, CA, 94550, USA
| | - Que N Van
- RAS Initiative, The Cancer Research Technology Program, Frederick National Laboratory, Frederick, MD, 21701, USA
| | - Constance Agamasu
- RAS Initiative, The Cancer Research Technology Program, Frederick National Laboratory, Frederick, MD, 21701, USA
| | - Marco Tonelli
- National Magnetic Resonance Facility at Madison, Biochemistry Department, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Fikret Aydin
- Physical and Life Sciences (PLS) Directorate, Lawrence Livermore National Laboratory, Livermore, CA, 94550, USA
| | - De Chen
- RAS Initiative, The Cancer Research Technology Program, Frederick National Laboratory, Frederick, MD, 21701, USA
| | - Gulcin Gulten
- RAS Initiative, The Cancer Research Technology Program, Frederick National Laboratory, Frederick, MD, 21701, USA
| | - James N Glosli
- Physical and Life Sciences (PLS) Directorate, Lawrence Livermore National Laboratory, Livermore, CA, 94550, USA
| | - Cesar A López
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Tomas Oppelstrup
- Physical and Life Sciences (PLS) Directorate, Lawrence Livermore National Laboratory, Livermore, CA, 94550, USA
| | - Chris Neale
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Sandrasegaram Gnanakaran
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - William K Gillette
- RAS Initiative, The Cancer Research Technology Program, Frederick National Laboratory, Frederick, MD, 21701, USA
| | - Helgi I Ingólfsson
- Physical and Life Sciences (PLS) Directorate, Lawrence Livermore National Laboratory, Livermore, CA, 94550, USA
| | - Felice C Lightstone
- Physical and Life Sciences (PLS) Directorate, Lawrence Livermore National Laboratory, Livermore, CA, 94550, USA
| | - Andrew G Stephen
- RAS Initiative, The Cancer Research Technology Program, Frederick National Laboratory, Frederick, MD, 21701, USA
| | - Frederick H Streitz
- Physical and Life Sciences (PLS) Directorate, Lawrence Livermore National Laboratory, Livermore, CA, 94550, USA
| | - Dwight V Nissley
- RAS Initiative, The Cancer Research Technology Program, Frederick National Laboratory, Frederick, MD, 21701, USA
| | - Thomas J Turbyville
- RAS Initiative, The Cancer Research Technology Program, Frederick National Laboratory, Frederick, MD, 21701, USA.
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4
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Whitley MJ, Tran TH, Rigby M, Yi M, Dharmaiah S, Waybright TJ, Ramakrishnan N, Perkins S, Taylor T, Messing S, Esposito D, Nissley DV, McCormick F, Stephen AG, Turbyville T, Cornilescu G, Simanshu DK. Comparative analysis of KRAS4a and KRAS4b splice variants reveals distinctive structural and functional properties. SCIENCE ADVANCES 2024; 10:eadj4137. [PMID: 38354232 DOI: 10.1126/sciadv.adj4137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 01/12/2024] [Indexed: 02/16/2024]
Abstract
KRAS, the most frequently mutated oncogene in human cancer, produces two isoforms, KRAS4a and KRAS4b, through alternative splicing. These isoforms differ in exon 4, which encodes the final 15 residues of the G-domain and hypervariable regions (HVRs), vital for trafficking and membrane localization. While KRAS4b has been extensively studied, KRAS4a has been largely overlooked. Our multidisciplinary study compared the structural and functional characteristics of KRAS4a and KRAS4b, revealing distinct structural properties and thermal stability. Position 151 influences KRAS4a's thermal stability, while position 153 affects binding to RAF1 CRD protein. Nuclear magnetic resonance analysis identified localized structural differences near sequence variations and provided a solution-state conformational ensemble. Notably, KRAS4a exhibits substantial transcript abundance in bile ducts, liver, and stomach, with transcript levels approaching KRAS4b in the colon and rectum. Functional disparities were observed in full-length KRAS variants, highlighting the impact of HVR variations on interaction with trafficking proteins and downstream effectors like RAF and PI3K within cells.
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Affiliation(s)
- Matthew J Whitley
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Timothy H Tran
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Megan Rigby
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Ming Yi
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Srisathiyanarayanan Dharmaiah
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Timothy J Waybright
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Nitya Ramakrishnan
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Shelley Perkins
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Troy Taylor
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Simon Messing
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Dominic Esposito
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Dwight V Nissley
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Frank McCormick
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, 1450 3rd Street, San Francisco, CA, USA
| | - Andrew G Stephen
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Thomas Turbyville
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Gabriel Cornilescu
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Dhirendra K Simanshu
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
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5
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Riaud M, Maxwell J, Soria-Bretones I, Dankner M, Li M, Rose AAN. The role of CRAF in cancer progression: from molecular mechanisms to precision therapies. Nat Rev Cancer 2024; 24:105-122. [PMID: 38195917 DOI: 10.1038/s41568-023-00650-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/27/2023] [Indexed: 01/11/2024]
Abstract
The RAF family of kinases includes key activators of the pro-tumourigenic mitogen-activated protein kinase pathway. Hyperactivation of RAF proteins, particularly BRAF and CRAF, drives tumour progression and drug resistance in many types of cancer. Although BRAF is the most studied RAF protein, partially owing to its high mutation incidence in melanoma, the role of CRAF in tumourigenesis and drug resistance is becoming increasingly clinically relevant. Here, we summarize the main known regulatory mechanisms and gene alterations that contribute to CRAF activity, highlighting the different oncogenic roles of CRAF, and categorize RAF1 (CRAF) mutations according to the effect on kinase activity. Additionally, we emphasize the effect that CRAF alterations may have on drug resistance and how precision therapies could effectively target CRAF-dependent tumours. Here, we discuss preclinical and clinical findings that may lead to improved treatments for all types of oncogenic RAF1 alterations in cancer.
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Affiliation(s)
- Melody Riaud
- Gerald Bronfman Department of Oncology, McGill University, Montreal, Quebec, Canada
- Lady Davis Institute, Jewish General Hospital, Montreal, Quebec, Canada
| | - Jennifer Maxwell
- Lady Davis Institute, Jewish General Hospital, Montreal, Quebec, Canada
- Division of Experimental Medicine, Faculty of Medicine, McGill University, Montreal, Quebec, Canada
| | - Isabel Soria-Bretones
- Gerald Bronfman Department of Oncology, McGill University, Montreal, Quebec, Canada
- Lady Davis Institute, Jewish General Hospital, Montreal, Quebec, Canada
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
| | - Matthew Dankner
- Lady Davis Institute, Jewish General Hospital, Montreal, Quebec, Canada
- Faculty of Medicine, McGill University, Montreal, Quebec, Canada
- Rosalind & Morris Goodman Cancer Institute, McGill University, Montreal, Quebec, Canada
| | - Meredith Li
- Gerald Bronfman Department of Oncology, McGill University, Montreal, Quebec, Canada
| | - April A N Rose
- Gerald Bronfman Department of Oncology, McGill University, Montreal, Quebec, Canada.
- Lady Davis Institute, Jewish General Hospital, Montreal, Quebec, Canada.
- Division of Experimental Medicine, Faculty of Medicine, McGill University, Montreal, Quebec, Canada.
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6
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Nussinov R, Jang H. Direct K-Ras Inhibitors to Treat Cancers: Progress, New Insights, and Approaches to Treat Resistance. Annu Rev Pharmacol Toxicol 2024; 64:231-253. [PMID: 37524384 DOI: 10.1146/annurev-pharmtox-022823-113946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/02/2023]
Abstract
Here we discuss approaches to K-Ras inhibition and drug resistance scenarios. A breakthrough offered a covalent drug against K-RasG12C. Subsequent innovations harnessed same-allele drug combinations, as well as cotargeting K-RasG12C with a companion drug to upstream regulators or downstream kinases. However, primary, adaptive, and acquired resistance inevitably emerge. The preexisting mutation load can explain how even exceedingly rare mutations with unobservable effects can promote drug resistance, seeding growth of insensitive cell clones, and proliferation. Statistics confirm the expectation that most resistance-related mutations are in cis, pointing to the high probability of cooperative, same-allele effects. In addition to targeted Ras inhibitors and drug combinations, bifunctional molecules and innovative tri-complex inhibitors to target Ras mutants are also under development. Since the identities and potential contributions of preexisting and evolving mutations are unknown, selecting a pharmacologic combination is taxing. Collectively, our broad review outlines considerations and provides new insights into pharmacology and resistance.
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Affiliation(s)
- Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Cancer Innovation Laboratory, National Cancer Institute, Frederick, Maryland, USA;
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Cancer Innovation Laboratory, National Cancer Institute, Frederick, Maryland, USA;
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7
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Taylor T, Gillette W. Production of Isotopically Labeled KRAS4b. Methods Mol Biol 2024; 2797:23-34. [PMID: 38570450 DOI: 10.1007/978-1-0716-3822-4_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2024]
Abstract
Isotopically labelled proteins are important reagents in structural biology as well as in targeted drug development. The field continues to advance with complex multi-isotope labeling. We have combined our experience in high-level soluble KRAS4b expression with protocols for isotope incorporation, to achieve reliable and efficient approaches for several labeling strategies. Typical experiments achieve nearly 100% 15N incorporation, with yields in the range of 1.3-24.6 mg/L (median = 6.4 mg/L, n = 53). Improvements in the growth parameters in the presence of deuterium reduce the standard time of fermentation from 5 days to 3 days by modifying the medium used during the weaning process. The methods described are compatible with multi-isotope labeling and site-specific labeling.
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Affiliation(s)
- Troy Taylor
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - William Gillette
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA.
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8
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Cornilescu G. 1D and 2D NMR for KRAS:Ligand Binding. Methods Mol Biol 2024; 2797:115-124. [PMID: 38570456 DOI: 10.1007/978-1-0716-3822-4_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2024]
Abstract
Fragment-based screening by ligand-observed 1D NMR and binding interface mapping by protein-observed 2D NMR are popular methods used in drug discovery. These methods allow researchers to detect compound binding over a wide range of affinities and offer a simultaneous assessment of solubility, purity, and chemical formula accuracy of the target compounds and the 15N-labeled protein when examined by 1D and 2D NMR, respectively. These methods can be applied for screening fragment binding to the active (GMPPNP-bound) and inactive (GDP-bound) states of oncogenic KRAS mutants.
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Affiliation(s)
- Gabriel Cornilescu
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA.
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9
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Nussinov R, Liu Y, Zhang W, Jang H. Protein conformational ensembles in function: roles and mechanisms. RSC Chem Biol 2023; 4:850-864. [PMID: 37920394 PMCID: PMC10619138 DOI: 10.1039/d3cb00114h] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 09/02/2023] [Indexed: 11/04/2023] Open
Abstract
The sequence-structure-function paradigm has dominated twentieth century molecular biology. The paradigm tacitly stipulated that for each sequence there exists a single, well-organized protein structure. Yet, to sustain cell life, function requires (i) that there be more than a single structure, (ii) that there be switching between the structures, and (iii) that the structures be incompletely organized. These fundamental tenets called for an updated sequence-conformational ensemble-function paradigm. The powerful energy landscape idea, which is the foundation of modernized molecular biology, imported the conformational ensemble framework from physics and chemistry. This framework embraces the recognition that proteins are dynamic and are always interconverting between conformational states with varying energies. The more stable the conformation the more populated it is. The changes in the populations of the states are required for cell life. As an example, in vivo, under physiological conditions, wild type kinases commonly populate their more stable "closed", inactive, conformations. However, there are minor populations of the "open", ligand-free states. Upon their stabilization, e.g., by high affinity interactions or mutations, their ensembles shift to occupy the active states. Here we discuss the role of conformational propensities in function. We provide multiple examples of diverse systems, including protein kinases, lipid kinases, and Ras GTPases, discuss diverse conformational mechanisms, and provide a broad outlook on protein ensembles in the cell. We propose that the number of molecules in the active state (inactive for repressors), determine protein function, and that the dynamic, relative conformational propensities, rather than the rigid structures, are the hallmark of cell life.
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Affiliation(s)
- Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research Frederick MD 21702 USA
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University Tel Aviv 69978 Israel
- Cancer Innovation Laboratory, National Cancer Institute Frederick MD 21702 USA
| | - Yonglan Liu
- Cancer Innovation Laboratory, National Cancer Institute Frederick MD 21702 USA
| | - Wengang Zhang
- Cancer Innovation Laboratory, National Cancer Institute Frederick MD 21702 USA
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research Frederick MD 21702 USA
- Cancer Innovation Laboratory, National Cancer Institute Frederick MD 21702 USA
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10
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Borges-Araújo L, Borges-Araújo AC, Ozturk TN, Ramirez-Echemendia DP, Fábián B, Carpenter TS, Thallmair S, Barnoud J, Ingólfsson HI, Hummer G, Tieleman DP, Marrink SJ, Souza PCT, Melo MN. Martini 3 Coarse-Grained Force Field for Cholesterol. J Chem Theory Comput 2023; 19:7387-7404. [PMID: 37796943 DOI: 10.1021/acs.jctc.3c00547] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/07/2023]
Abstract
Cholesterol plays a crucial role in biomembranes by regulating various properties, such as fluidity, rigidity, permeability, and organization of lipid bilayers. The latest version of the Martini model, Martini 3, offers significant improvements in interaction balance, molecular packing, and inclusion of new bead types and sizes. However, the release of the new model resulted in the need to reparameterize many core molecules, including cholesterol. Here, we describe the development and validation of a Martini 3 cholesterol model, addressing issues related to its bonded setup, shape, volume, and hydrophobicity. The proposed model mitigates some limitations of its Martini 2 predecessor while maintaining or improving the overall behavior.
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Affiliation(s)
- Luís Borges-Araújo
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
- Molecular Microbiology and Structural Biochemistry, UMR 5086 CNRS & University of Lyon, 7 Passage du Vercors, Lyon F-69367, France
| | - Ana C Borges-Araújo
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Tugba Nur Ozturk
- Physical and Life Sciences (PLS) Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Daniel P Ramirez-Echemendia
- Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada, T2N 1N4
| | - Balázs Fábián
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Max-von-Laue Straße 3, 60438 Frankfurt am Main, Germany
| | - Timothy S Carpenter
- Physical and Life Sciences (PLS) Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Sebastian Thallmair
- Frankfurt Institute for Advanced Studies, Ruth-Moufang-Straße 1, 60438 Frankfurt am Main, Germany
| | - Jonathan Barnoud
- Centre for Computational Chemistry, School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
- CiTIUS Intelligent Technologies Research Centre, University of Santiago de Compostela, Rúa de Jenaro de la Fuente, 15705 Santiago de Compostela, Spain
| | - Helgi I Ingólfsson
- Physical and Life Sciences (PLS) Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Gerhard Hummer
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Max-von-Laue Straße 3, 60438 Frankfurt am Main, Germany
- Institute of Biophysics, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - D Peter Tieleman
- Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada, T2N 1N4
| | - Siewert J Marrink
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Paulo C T Souza
- Molecular Microbiology and Structural Biochemistry, UMR 5086 CNRS & University of Lyon, 7 Passage du Vercors, Lyon F-69367, France
| | - Manuel N Melo
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
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11
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Morstein J, Shrestha R, Van QN, López CA, Arora N, Tonelli M, Liang H, Chen D, Zhou Y, Hancock JF, Stephen AG, Turbyville TJ, Shokat KM. Direct Modulators of K-Ras-Membrane Interactions. ACS Chem Biol 2023; 18:2082-2093. [PMID: 37579045 PMCID: PMC10510109 DOI: 10.1021/acschembio.3c00413] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 07/31/2023] [Indexed: 08/16/2023]
Abstract
Protein-membrane interactions (PMIs) are ubiquitous in cellular signaling. Initial steps of signal transduction cascades often rely on transient and dynamic interactions with the inner plasma membrane leaflet to populate and regulate signaling hotspots. Methods to target and modulate these interactions could yield attractive tool compounds and drug candidates. Here, we demonstrate that the conjugation of a medium-chain lipid tail to the covalent K-Ras(G12C) binder MRTX849 at a solvent-exposed site enables such direct modulation of PMIs. The conjugated lipid tail interacts with the tethered membrane and changes the relative membrane orientation and conformation of K-Ras(G12C), as shown by molecular dynamics (MD) simulation-supported NMR studies. In cells, this PMI modulation restricts the lateral mobility of K-Ras(G12C) and disrupts nanoclusters. The described strategy could be broadly applicable to selectively modulate transient PMIs.
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Affiliation(s)
- Johannes Morstein
- Department
of Cellular and Molecular Pharmacology and Howard Hughes Medical Institute, University of California, San Francisco, California 94158, United States
| | - Rebika Shrestha
- NCI
RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21701, United States
| | - Que N. Van
- NCI
RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21701, United States
| | - César A. López
- Theoretical
Biology and Biophysics Group, Los Alamos
National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Neha Arora
- Department
of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center, Houston, Texas 77030, United States
| | - Marco Tonelli
- National
Magnetic Resonance Facility at Madison, Biochemistry Department, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Hong Liang
- Department
of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center, Houston, Texas 77030, United States
| | - De Chen
- NCI
RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21701, United States
| | - Yong Zhou
- Department
of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center, Houston, Texas 77030, United States
| | - John F. Hancock
- Department
of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center, Houston, Texas 77030, United States
| | - Andrew G. Stephen
- NCI
RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21701, United States
| | - Thomas J. Turbyville
- NCI
RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21701, United States
| | - Kevan M. Shokat
- Department
of Cellular and Molecular Pharmacology and Howard Hughes Medical Institute, University of California, San Francisco, California 94158, United States
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12
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Chao FA, Chan AH, Dharmaiah S, Schwieters CD, Tran TH, Taylor T, Ramakrishnan N, Esposito D, Nissley DV, McCormick F, Simanshu DK, Cornilescu G. Reduced dynamic complexity allows structure elucidation of an excited state of KRAS G13D. Commun Biol 2023; 6:594. [PMID: 37268708 DOI: 10.1038/s42003-023-04960-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Accepted: 05/19/2023] [Indexed: 06/04/2023] Open
Abstract
Localized dynamics of RAS, including regions distal to the nucleotide-binding site, is of high interest for elucidating the mechanisms by which RAS proteins interact with effectors and regulators and for designing inhibitors. Among several oncogenic mutants, methyl relaxation dispersion experiments reveal highly synchronized conformational dynamics in the active (GMPPNP-bound) KRASG13D, which suggests an exchange between two conformational states in solution. Methyl and 31P NMR spectra of active KRASG13D in solution confirm a two-state ensemble interconverting on the millisecond timescale, with a major Pγ atom peak corresponding to the dominant State 1 conformation and a secondary peak indicating an intermediate state different from the known State 2 conformation recognized by RAS effectors. High-resolution crystal structures of active KRASG13D and KRASG13D-RAF1 RBD complex provide snapshots of the State 1 and 2 conformations, respectively. We use residual dipolar couplings to solve and cross-validate the structure of the intermediate state of active KRASG13D, showing a conformation distinct from those of States 1 and 2 outside the known flexible switch regions. The dynamic coupling between the conformational exchange in the effector lobe and the breathing motion in the allosteric lobe is further validated by a secondary mutation in the allosteric lobe, which affects the conformational population equilibrium.
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Affiliation(s)
- Fa-An Chao
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Frederick, MD, 21701, USA.
| | - Albert H Chan
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Frederick, MD, 21701, USA
| | - Srisathiyanarayanan Dharmaiah
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Frederick, MD, 21701, USA
| | - Charles D Schwieters
- Division of Computational Bioscience, Center for Information Technology, National Institutes of Health, Building 12A, 20892-5624, Bethesda, MD, USA
| | - Timothy H Tran
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Frederick, MD, 21701, USA
| | - Troy Taylor
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Frederick, MD, 21701, USA
| | - Nitya Ramakrishnan
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Frederick, MD, 21701, USA
| | - Dominic Esposito
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Frederick, MD, 21701, USA
| | - Dwight V Nissley
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Frederick, MD, 21701, USA
| | - Frank McCormick
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Frederick, MD, 21701, USA
- Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, 1450 3rd Street, San Francisco, CA, 94158, USA
| | - Dhirendra K Simanshu
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Frederick, MD, 21701, USA.
| | - Gabriel Cornilescu
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Frederick, MD, 21701, USA.
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13
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Spencer-Smith R, Terrell EM, Insinna C, Agamasu C, Wagner ME, Ritt DA, Stauffer J, Stephen AG, Morrison DK. RASopathy mutations provide functional insight into the BRAF cysteine-rich domain and reveal the importance of autoinhibition in BRAF regulation. Mol Cell 2022; 82:4262-4276.e5. [PMID: 36347258 PMCID: PMC9677513 DOI: 10.1016/j.molcel.2022.10.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 07/16/2022] [Accepted: 10/14/2022] [Indexed: 11/09/2022]
Abstract
BRAF is frequently mutated in human cancer and the RASopathy syndromes, with RASopathy mutations often observed in the cysteine-rich domain (CRD). Although the CRD participates in phosphatidylserine (PS) binding, the RAS-RAF interaction, and RAF autoinhibition, the impact of these activities on RAF function in normal and disease states is not well characterized. Here, we analyze a panel of CRD mutations and show that they increase BRAF activity by relieving autoinhibition and/or enhancing PS binding, with relief of autoinhibition being the major factor determining mutation severity. Further, we show that CRD-mediated autoinhibition prevents the constitutive plasma membrane localization of BRAF that causes increased RAS-dependent and RAS-independent function. Comparison of the BRAF- and CRAF-CRDs also indicates that the BRAF-CRD is a stronger mediator of autoinhibition and PS binding, and given the increased catalytic activity of BRAF, our studies reveal a more critical role for CRD-mediated autoinhibition in BRAF regulation.
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Affiliation(s)
- Russell Spencer-Smith
- Laboratory of Cell and Developmental Signaling, Center for Cancer Research, National Cancer Institute-Frederick, Frederick, MD 21702 USA
| | - Elizabeth M Terrell
- Laboratory of Cell and Developmental Signaling, Center for Cancer Research, National Cancer Institute-Frederick, Frederick, MD 21702 USA
| | - Christine Insinna
- Laboratory of Cell and Developmental Signaling, Center for Cancer Research, National Cancer Institute-Frederick, Frederick, MD 21702 USA
| | - Constance Agamasu
- National Cancer Institute RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, MD 21702 USA
| | - Morgan E Wagner
- National Cancer Institute RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, MD 21702 USA
| | - Daniel A Ritt
- Laboratory of Cell and Developmental Signaling, Center for Cancer Research, National Cancer Institute-Frederick, Frederick, MD 21702 USA
| | - Jim Stauffer
- Laboratory of Cell and Developmental Signaling, Center for Cancer Research, National Cancer Institute-Frederick, Frederick, MD 21702 USA
| | - Andrew G Stephen
- National Cancer Institute RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, MD 21702 USA
| | - Deborah K Morrison
- Laboratory of Cell and Developmental Signaling, Center for Cancer Research, National Cancer Institute-Frederick, Frederick, MD 21702 USA.
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14
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Nguyen K, López CA, Neale C, Van QN, Carpenter TS, Di Natale F, Travers T, Tran TH, Chan AH, Bhatia H, Frank PH, Tonelli M, Zhang X, Gulten G, Reddy T, Burns V, Oppelstrup T, Hengartner N, Simanshu DK, Bremer PT, Chen D, Glosli JN, Shrestha R, Turbyville T, Streitz FH, Nissley DV, Ingólfsson HI, Stephen AG, Lightstone FC, Gnanakaran S. Exploring CRD mobility during RAS/RAF engagement at the membrane. Biophys J 2022; 121:3630-3650. [PMID: 35778842 PMCID: PMC9617161 DOI: 10.1016/j.bpj.2022.06.035] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 06/21/2022] [Accepted: 06/28/2022] [Indexed: 11/25/2022] Open
Abstract
During the activation of mitogen-activated protein kinase (MAPK) signaling, the RAS-binding domain (RBD) and cysteine-rich domain (CRD) of RAF bind to active RAS at the plasma membrane. The orientation of RAS at the membrane may be critical for formation of the RAS-RBDCRD complex and subsequent signaling. To explore how RAS membrane orientation relates to the protein dynamics within the RAS-RBDCRD complex, we perform multiscale coarse-grained and all-atom molecular dynamics (MD) simulations of KRAS4b bound to the RBD and CRD domains of RAF-1, both in solution and anchored to a model plasma membrane. Solution MD simulations describe dynamic KRAS4b-CRD conformations, suggesting that the CRD has sufficient flexibility in this environment to substantially change its binding interface with KRAS4b. In contrast, when the ternary complex is anchored to the membrane, the mobility of the CRD relative to KRAS4b is restricted, resulting in fewer distinct KRAS4b-CRD conformations. These simulations implicate membrane orientations of the ternary complex that are consistent with NMR measurements. While a crystal structure-like conformation is observed in both solution and membrane simulations, a particular intermolecular rearrangement of the ternary complex is observed only when it is anchored to the membrane. This configuration emerges when the CRD hydrophobic loops are inserted into the membrane and helices α3-5 of KRAS4b are solvent exposed. This membrane-specific configuration is stabilized by KRAS4b-CRD contacts that are not observed in the crystal structure. These results suggest modulatory interplay between the CRD and plasma membrane that correlate with RAS/RAF complex structure and dynamics, and potentially influence subsequent steps in the activation of MAPK signaling.
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Affiliation(s)
- Kien Nguyen
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, New Mexico
| | - Cesar A López
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, New Mexico
| | - Chris Neale
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, New Mexico
| | - Que N Van
- National Cancer Institute RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland
| | - Timothy S Carpenter
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California
| | - Francesco Di Natale
- Applications, Simulations, and Quality, Lawrence Livermore National Laboratory, Livermore, California
| | | | - Timothy H Tran
- National Cancer Institute RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland
| | - Albert H Chan
- National Cancer Institute RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland
| | - Harsh Bhatia
- Center for Applied Scientific Computing, Lawrence Livermore National Laboratory, Livermore, California
| | - Peter H Frank
- National Cancer Institute RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland
| | - Marco Tonelli
- National Magnetic Resonance Facility at Madison, Biochemistry Department, University of Wisconsin-Madison, Madison, Wisconsin
| | - Xiaohua Zhang
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California
| | - Gulcin Gulten
- National Cancer Institute RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland
| | - Tyler Reddy
- CCS-7, Los Alamos National Laboratory, Los Alamos, New Mexico
| | - Violetta Burns
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, New Mexico
| | - Tomas Oppelstrup
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California
| | - Nick Hengartner
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, New Mexico
| | - Dhirendra K Simanshu
- National Cancer Institute RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland
| | - Peer-Timo Bremer
- Center for Applied Scientific Computing, Lawrence Livermore National Laboratory, Livermore, California
| | - De Chen
- National Cancer Institute RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland
| | - James N Glosli
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California
| | - Rebika Shrestha
- National Cancer Institute RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland
| | - Thomas Turbyville
- National Cancer Institute RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland
| | - Frederick H Streitz
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California
| | - Dwight V Nissley
- National Cancer Institute RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland
| | - Helgi I Ingólfsson
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California
| | - Andrew G Stephen
- National Cancer Institute RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland
| | - Felice C Lightstone
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California
| | - Sandrasegaram Gnanakaran
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, New Mexico.
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15
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Nussinov R, Zhang M, Maloney R, Liu Y, Tsai CJ, Jang H. Allostery: Allosteric Cancer Drivers and Innovative Allosteric Drugs. J Mol Biol 2022; 434:167569. [PMID: 35378118 PMCID: PMC9398924 DOI: 10.1016/j.jmb.2022.167569] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 03/11/2022] [Accepted: 03/25/2022] [Indexed: 01/12/2023]
Abstract
Here, we discuss the principles of allosteric activating mutations, propagation downstream of the signals that they prompt, and allosteric drugs, with examples from the Ras signaling network. We focus on Abl kinase where mutations shift the landscape toward the active, imatinib binding-incompetent conformation, likely resulting in the high affinity ATP outcompeting drug binding. Recent pharmacological innovation extends to allosteric inhibitor (GNF-5)-linked PROTAC, targeting Bcr-Abl1 myristoylation site, and broadly, allosteric heterobifunctional degraders that destroy targets, rather than inhibiting them. Designed chemical linkers in bifunctional degraders can connect the allosteric ligand that binds the target protein and the E3 ubiquitin ligase warhead anchor. The physical properties and favored conformational state of the engineered linker can precisely coordinate the distance and orientation between the target and the recruited E3. Allosteric PROTACs, noncompetitive molecular glues, and bitopic ligands, with covalent links of allosteric ligands and orthosteric warheads, increase the effective local concentration of productively oriented and placed ligands. Through covalent chemical or peptide linkers, allosteric drugs can collaborate with competitive drugs, degrader anchors, or other molecules of choice, driving innovative drug discovery.
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Affiliation(s)
- Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA; Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel.
| | - Mingzhen Zhang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA
| | - Ryan Maloney
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA
| | - Yonglan Liu
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA
| | - Chung-Jung Tsai
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA
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16
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Szondy Z, Al-Zaeed N, Tarban N, Fige É, Garabuczi É, Sarang Z. Involvement of phosphatidylserine receptors in the skeletal muscle regeneration: therapeutic implications. J Cachexia Sarcopenia Muscle 2022; 13:1961-1973. [PMID: 35666022 PMCID: PMC9397555 DOI: 10.1002/jcsm.13024] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 04/09/2022] [Accepted: 05/09/2022] [Indexed: 12/13/2022] Open
Abstract
Sarcopenia is a progressive loss of muscle mass and strength with a risk of adverse outcomes such as disability, poor quality of life, and death. Increasing evidence indicates that diminished ability of the muscle to activate satellite cell-dependent regeneration is one of the factors that might contribute to its development. Skeletal muscle regeneration following myogenic cell death results from the proliferation and differentiation of myogenic stem cells, called satellite cells, located beneath the basal lamina of the muscle fibres. Satellite cell differentiation is not a satellite cell-autonomous process but depends on signals provided by the surrounding cells. Infiltrating macrophages play a key role in the process partly by clearing the necrotic cell debris, partly by producing cytokines and growth factors that guide myogenesis. At the beginning of the muscle regeneration process, macrophages are pro-inflammatory, and the cytokines produced by them trigger the proliferation and differentiation of satellite cells. Following the uptake of dead cells, however, a transcriptionally regulated phenotypic change (macrophage polarization) is induced in them resulting in their transformation into healing macrophages that guide resolution of inflammation, completion of myoblast differentiation, myoblast fusion and growth, and return to homeostasis. Impaired efferocytosis results in delayed cell death clearance, delayed macrophage polarization, prolonged inflammation, and impaired muscle regeneration. Thus, proper efferocytosis by macrophages is a determining factor during muscle repair. Here we review that both efferocytosis and myogenesis are dependent on the cell surface phosphatidylserine (PS), and surprisingly, these two processes share a number of common PS receptors and signalling pathways. Based on these findings, we propose that stimulating the function of PS receptors for facilitating muscle repair following injury could be a successful approach, as it would enhance efferocytosis and myogenesis simultaneously. Because increasing evidence indicates a pathophysiological role of impaired efferocytosis in the development of chronic inflammatory conditions, as well as in impaired muscle regeneration both contributing to the development of sarcopenia, improving efferocytosis should be considered also in its management. Again applying or combining those treatments that target PS receptors would be expected to be the most effective, because they would also promote myogenesis. A potential PS receptor-triggering candidate molecule is milk fat globule-EGF-factor 8 (MFG-E8), which not only stimulates PS-dependent efferocytosis and myoblast fusion but also promotes extracellular signal-regulated kinase (ERK) and Akt activation-mediated cell proliferation and cell cycle progression in myoblasts.
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Affiliation(s)
- Zsuzsa Szondy
- Section of Dental Biochemistry, Department of Basic Medical Sciences, Faculty of Dentistry, University of Debrecen, Debrecen, Hungary.,Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Nour Al-Zaeed
- Doctoral School of Molecular Cell and Immune Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Nastaran Tarban
- Doctoral School of Molecular Cell and Immune Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Éva Fige
- Section of Dental Biochemistry, Department of Basic Medical Sciences, Faculty of Dentistry, University of Debrecen, Debrecen, Hungary
| | - Éva Garabuczi
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Zsolt Sarang
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
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17
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Bhatia H, Thiagarajan JJ, Anirudh R, TS J, Oppelstrup T, Ingólfsson HI, Lightstone F, Bremer PT. A Biology-Informed Similarity Metric for Simulated Patches of Human Cell Membrane. MACHINE LEARNING: SCIENCE AND TECHNOLOGY 2022. [DOI: 10.1088/2632-2153/ac8523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Abstract
Complex scientific inquiries rely increasingly upon large and autonomous multiscale simulation campaigns, which fundamentally require similarity metrics to quantify “sufficient” changes among data and/or configurations. However, subject matter experts are often unable to articulate similarity precisely or in terms of well-formulated definitions, especially when new hypotheses are to be explored, making it challenging to design a meaningful metric. Furthermore, the key to practical usefulness of such metrics to enable autonomous simulations lies in in situ inference, which requires generalization to possibly substantial distributional shifts in unseen, future data. Here, we address these challenges in a cancer biology application and develop a meaningful similarity metric for “patches”— regions of simulated human cell membrane that express interactions between certain proteins of interest and relevant lipids. In the absence of well-defined conditions for similarity, we leverage several biology-informed notions about data and the underlying simulations to impose inductive biases on our metric learning framework, resulting in a suitable similarity metric that also generalizes well to significant distributional shifts encountered during the deployment. We combine these intuitions to organize the learned embedding space in a multiscale manner, which makes the metric robust to incomplete and even contradictory intuitions. Our approach delivers a metric that not only performs well on the conditions used for its development and other relevant criteria, but also learns key spatiotemporal relationships from statistical mechanics without ever being exposed to any such information during training.
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18
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López CA, Zhang X, Aydin F, Shrestha R, Van QN, Stanley CB, Carpenter TS, Nguyen K, Patel LA, Chen D, Burns V, Hengartner NW, Reddy TJE, Bhatia H, Di Natale F, Tran TH, Chan AH, Simanshu DK, Nissley DV, Streitz FH, Stephen AG, Turbyville TJ, Lightstone FC, Gnanakaran S, Ingólfsson HI, Neale C. Asynchronous Reciprocal Coupling of Martini 2.2 Coarse-Grained and CHARMM36 All-Atom Simulations in an Automated Multiscale Framework. J Chem Theory Comput 2022; 18:5025-5045. [PMID: 35866871 DOI: 10.1021/acs.jctc.2c00168] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The appeal of multiscale modeling approaches is predicated on the promise of combinatorial synergy. However, this promise can only be realized when distinct scales are combined with reciprocal consistency. Here, we consider multiscale molecular dynamics (MD) simulations that combine the accuracy and macromolecular flexibility accessible to fixed-charge all-atom (AA) representations with the sampling speed accessible to reductive, coarse-grained (CG) representations. AA-to-CG conversions are relatively straightforward because deterministic routines with unique outcomes are achievable. Conversely, CG-to-AA conversions have many solutions due to a surge in the number of degrees of freedom. While automated tools for biomolecular CG-to-AA transformation exist, we find that one popular option, called Backward, is prone to stochastic failure and the AA models that it does generate frequently have compromised protein structure and incorrect stereochemistry. Although these shortcomings can likely be circumvented by human intervention in isolated instances, automated multiscale coupling requires reliable and robust scale conversion. Here, we detail an extension to Multiscale Machine-learned Modeling Infrastructure (MuMMI), including an improved CG-to-AA conversion tool called sinceCG. This tool is reliable (∼98% weakly correlated repeat success rate), automatable (no unrecoverable hangs), and yields AA models that generally preserve protein secondary structure and maintain correct stereochemistry. We describe how the MuMMI framework identifies CG system configurations of interest, converts them to AA representations, and simulates them at the AA scale while on-the-fly analyses provide feedback to update CG parameters. Application to systems containing the peripheral membrane protein RAS and proximal components of RAF kinase on complex eight-component lipid bilayers with ∼1.5 million atoms is discussed in the context of MuMMI.
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Affiliation(s)
- Cesar A López
- Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Xiaohua Zhang
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Fikret Aydin
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Rebika Shrestha
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21701, United States
| | - Que N Van
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21701, United States
| | - Christopher B Stanley
- Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Timothy S Carpenter
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Kien Nguyen
- Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Lara A Patel
- Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States.,Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - De Chen
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21701, United States
| | - Violetta Burns
- Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Nicolas W Hengartner
- Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Tyler J E Reddy
- Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Harsh Bhatia
- Computing Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Francesco Di Natale
- Computing Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Timothy H Tran
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21701, United States
| | - Albert H Chan
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21701, United States
| | - Dhirendra K Simanshu
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21701, United States
| | - Dwight V Nissley
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21701, United States
| | - Frederick H Streitz
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Andrew G Stephen
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21701, United States
| | - Thomas J Turbyville
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21701, United States
| | - Felice C Lightstone
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Sandrasegaram Gnanakaran
- Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Helgi I Ingólfsson
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Chris Neale
- Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
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19
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Araya MK, Gorfe AA. Phosphatidylserine and Phosphatidylethanolamine Asymmetry Have a Negligible Effect on the Global Structure, Dynamics, and Interactions of the KRAS Lipid Anchor. J Phys Chem B 2022; 126:4491-4500. [PMID: 35687481 DOI: 10.1021/acs.jpcb.2c01253] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The intrinsically disordered C-terminus of the prominent oncogenic protein KRAS-4B (KRAS) selectively interacts and clusters with phosphatidylserine (PS) lipids in the plasma membrane (PM). This 11-residue segment, called tK, contains a polybasic domain (PBD) of six contiguous lysine residues and a farnesylated cysteine. Previous molecular dynamics (MD) simulation studies of tK in phosphatidylcholine (PC)/PS bilayers have suggested that backbone conformational dynamics modulate tK-PS interactions. These simulations have been conducted in symmetric membranes whereas the PM is compositionally asymmetric, with the inner leaflet, where KRAS is localized, being enriched with PS and phosphatidylethanolamine (PE) lipids. To examine if bilayer asymmetry affects tK conformational dynamics and interaction with lipids, we conducted two 10 μs long MD simulations of tK bound to a PC/PS and a PC/PS/PE bilayer in which the PS and PE lipids are distributed in one leaflet. We found that, first, these compositional asymmetries caused differences in acyl chain dynamics between leaflets, but the equilibrium structural and dynamic properties of the two asymmetric bilayers are similar; second, in both systems tK is highly dynamic and samples at least two distinct conformational states; third, PS-tK hydrogen-bonding interactions vary with peptide backbone conformations, and lysine side chains in the PBD predominantly interact with the serine oxygens of PS. These results are in good agreement with previous observations of tK in symmetric membranes. The effects of POPS asymmetry or the presence of POPE on tK are limited to modulating the relative contribution of individual side chains to interactions with lipids and redistributing conformational substates. Additional observations include the larger flexibility of tK in the current simulations, which we attribute to the longer duration of the simulations and the use of the CHARMM36m force field, which more accurately models intrinsically disordered peptides such as tK.
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Affiliation(s)
- Mussie K Araya
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center at Houston, 6431 Fannin St., Houston, Texas 77030, United States
| | - Alemayehu A Gorfe
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center at Houston, 6431 Fannin St., Houston, Texas 77030, United States
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20
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Maloney RC, Zhang M, Liu Y, Jang H, Nussinov R. The mechanism of activation of MEK1 by B-Raf and KSR1. Cell Mol Life Sci 2022; 79:281. [PMID: 35508574 PMCID: PMC9068654 DOI: 10.1007/s00018-022-04296-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 04/04/2022] [Accepted: 04/07/2022] [Indexed: 12/01/2022]
Abstract
MEK1 interactions with B-Raf and KSR1 are key steps in Ras/Raf/MEK/ERK signaling. Despite this, vital mechanistic details of how these execute signal transduction are still enigmatic. Among these is why, despite B-Raf and KSR1 kinase domains similarity, the B-Raf/MEK1 and KSR1/MEK1 complexes have distinct contributions to MEK1 activation, and broadly, what is KSR1's role. Our molecular dynamics simulations clarify these still unresolved ambiguities. Our results reveal that the proline-rich (P-rich) loop of MEK1 plays a decisive role in MEK1 activation loop (A-loop) phosphorylation. In the inactive B-Raf/MEK1 heterodimer, the collapsed A-loop of B-Raf interacts with the P-rich loop and A-loop of MEK1, minimizing MEK1 A-loop fluctuation and preventing it from phosphorylation. In the active B-Raf/MEK1 heterodimer, the P-rich loop moves in concert with the A-loop of B-Raf as it extends. This reduces the number of residues interacting with MEK1 A-loop, allowing increased A-loop fluctuation, and bringing Ser222 closer to ATP for phosphorylation. B-Raf αG-helix Arg662 promotes MEK1 activation by orienting Ser218 towards ATP. In KSR1/MEK1, the KSR1 αG-helix has Ala826 in place of B-Raf Arg662. This difference results in much fewer interactions between KSR1 αG-helix and MEK1 A-loop, thus a more flexible A-loop. We postulate that if KSR1 were to adopt an active configuration with an extended A-loop as seen in other protein kinases, then the MEK1 P-rich loop would extend in a similar manner, as seen in the active B-Raf/MEK1 heterodimer. This would result in highly flexible MEK1 A-loop, and KSR1 functioning as an active, B-Raf-like, kinase.
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Affiliation(s)
- Ryan C Maloney
- Cancer Innovation Laboratory, National Cancer Institute, Frederick, MD, 21702, USA
| | - Mingzhen Zhang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research, Frederick, MD, 21702, USA
| | - Yonglan Liu
- Cancer Innovation Laboratory, National Cancer Institute, Frederick, MD, 21702, USA
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research, Frederick, MD, 21702, USA
| | - Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research, Frederick, MD, 21702, USA.
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, 69978, Tel Aviv, Israel.
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21
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Simanshu DK, Morrison DK. A Structure is Worth a Thousand Words: New Insights for RAS and RAF Regulation. Cancer Discov 2022; 12:899-912. [PMID: 35046094 PMCID: PMC8983508 DOI: 10.1158/2159-8290.cd-21-1494] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 12/13/2021] [Accepted: 12/14/2021] [Indexed: 11/16/2022]
Abstract
The RAS GTPases are frequently mutated in human cancer, with KRAS being the predominant tumor driver. For many years, it has been known that the structure and function of RAS are integrally linked, as structural changes induced by GTP binding or mutational events determine the ability of RAS to interact with regulators and effectors. Recently, a wealth of information has emerged from structures of specific KRAS mutants and from structures of multiprotein complexes containing RAS and/or RAF, an essential effector of RAS. These structures provide key insights regarding RAS and RAF regulation as well as promising new strategies for therapeutic intervention. SIGNIFICANCE The RAS GTPases are major drivers of tumorigenesis, and for RAS proteins to exert their full oncogenic potential, they must interact with the RAF kinases to initiate ERK cascade signaling. Although binding to RAS is typically a prerequisite for RAF to become an activated kinase, determining the molecular mechanisms by which this interaction results in RAF activation has been a challenging task. A major advance in understanding this process and RAF regulation has come from recent structural studies of various RAS and RAF multiprotein signaling complexes, revealing new avenues for drug discovery.
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Affiliation(s)
- Dhirendra K. Simanshu
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, Maryland
| | - Deborah K. Morrison
- Laboratory of Cell and Developmental Signaling, Center for Cancer Research, National Cancer Institute, Frederick, Maryland
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22
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Waninger JJ, Beyett TS, Gadkari VV, Siebenaler RF, Kenum C, Shankar S, Ruotolo BT, Chinnaiyan AM, Tesmer JJ. Biochemical characterization of the interaction between KRAS and Argonaute 2. Biochem Biophys Rep 2022; 29:101191. [PMID: 34988297 PMCID: PMC8695255 DOI: 10.1016/j.bbrep.2021.101191] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 12/09/2021] [Accepted: 12/14/2021] [Indexed: 12/01/2022] Open
Abstract
Oncogenic mutations in KRAS result in a constitutively active, GTP-bound form that in turn activates many proliferative pathways. However, because of its compact and simple architecture, directly targeting KRAS with small molecule drugs has been challenging. Another approach is to identify targetable proteins that interact with KRAS. Argonaute 2 (AGO2) was recently identified as a protein that facilitates RAS-driven oncogenesis. Whereas previous studies described the in vivo effect of AGO2 on cancer progression in cells harboring mutated KRAS, here we sought to examine their direct interaction using purified proteins. We show that full length AGO2 co-immunoprecipitates with KRAS using purified components, however, a complex between FL AGO2 and KRAS could not be isolated. We also generated a smaller N-terminal fragment of AGO2 (NtAGO2) which is believed to represent the primary binding site of KRAS. A complex with NtAGO2 could be detected via ion-mobility mass spectrometry and size exclusion chromatography. However, the data suggest that the interaction of KRAS with purified AGO2 (NtAGO2 or FL AGO2) is weak and likely requires additional cellular components or proteo-forms of AGO2 that are not readily available in our purified assay systems. Future studies are needed to determine what conformation or modifications of AGO2 are necessary to enrich KRAS association and regulate its activities.
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Affiliation(s)
- Jessica J. Waninger
- Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, 48109, USA
- Department of Medical Education, University of Michigan, Ann Arbor, MI, USA
- Department of Cellular and Molecular Biology, University of Michigan, Ann Arbor, MI, USA
- Rogel Cancer Center, University of Michigan, Ann Arbor, MI, USA
| | - Tyler S. Beyett
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Varun V. Gadkari
- Department of Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Ronald F. Siebenaler
- Department of Medical Education, University of Michigan, Ann Arbor, MI, USA
- Rogel Cancer Center, University of Michigan, Ann Arbor, MI, USA
| | - Carson Kenum
- Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Sunita Shankar
- Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, 48109, USA
- Department of Pathology, University of Michigan, Ann Arbor, MI, USA
- Rogel Cancer Center, University of Michigan, Ann Arbor, MI, USA
| | | | - Arul M. Chinnaiyan
- Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, 48109, USA
- Department of Pathology, University of Michigan, Ann Arbor, MI, USA
- Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Urology, University of Michigan, Ann Arbor, MI, USA
- Rogel Cancer Center, University of Michigan, Ann Arbor, MI, USA
| | - John J.G. Tesmer
- Departments of Biological Sciences and Medicinal Chemistry & Molecular Pharmacology, Purdue University, Indiana, USA
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23
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Pavic K, Chippalkatti R, Abankwa D. Drug targeting opportunities en route to Ras nanoclusters. Adv Cancer Res 2022; 153:63-99. [PMID: 35101236 DOI: 10.1016/bs.acr.2021.07.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Disruption of the native membrane organization of Ras by the farnesyltransferase inhibitor tipifarnib in the late 1990s constituted the first indirect approach to drug target Ras. Since then, our understanding of how dynamically Ras shuttles between subcellular locations has changed significantly. Ras proteins have to arrive at the plasma membrane for efficient MAPK-signal propagation. On the plasma membrane Ras proteins are organized into isoform specific proteo-lipid assemblies called nanocluster. Recent evidence suggests that Ras nanocluster have a specific lipid composition, which supports the recruitment of effectors such as Raf. Conversely, effectors possess lipid-recognition motifs, which appear to serve as co-incidence detectors for the lipid domain of a given Ras isoform. Evidence suggests that dimeric Raf proteins then co-assemble dimeric Ras in an immobile complex, thus forming the minimal unit of an active nanocluster. Here we review established and novel trafficking chaperones and trafficking factors of Ras, along with the set of lipid and protein modulators of Ras nanoclustering. We highlight drug targeting approaches and opportunities against these determinants of functional Ras membrane organization. Finally, we reflect on implications for Ras signaling in polarized cells, such as epithelia, which are a common origin of tumorigenesis.
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Affiliation(s)
- Karolina Pavic
- Cancer Cell Biology and Drug Discovery Group, Department of Life Sciences and Medicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Rohan Chippalkatti
- Cancer Cell Biology and Drug Discovery Group, Department of Life Sciences and Medicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Daniel Abankwa
- Cancer Cell Biology and Drug Discovery Group, Department of Life Sciences and Medicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg.
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24
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Abstract
The RASopathies are a group of disorders caused by a germline mutation in one of the genes encoding a component of the RAS/MAPK pathway. These disorders, including neurofibromatosis type 1, Noonan syndrome, cardiofaciocutaneous syndrome, Costello syndrome and Legius syndrome, among others, have overlapping clinical features due to RAS/MAPK dysfunction. Although several of the RASopathies are very rare, collectively, these disorders are relatively common. In this Review, we discuss the pathogenesis of the RASopathy-associated genetic variants and the knowledge gained about RAS/MAPK signaling that resulted from studying RASopathies. We also describe the cell and animal models of the RASopathies and explore emerging RASopathy genes. Preclinical and clinical experiences with targeted agents as therapeutics for RASopathies are also discussed. Finally, we review how the recently developed drugs targeting RAS/MAPK-driven malignancies, such as inhibitors of RAS activation, direct RAS inhibitors and RAS/MAPK pathway inhibitors, might be leveraged for patients with RASopathies.
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Affiliation(s)
- Katie E Hebron
- Pediatric Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
| | - Edjay Ralph Hernandez
- Pediatric Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
| | - Marielle E Yohe
- Pediatric Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
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25
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Ingólfsson HI, Neale C, Carpenter TS, Shrestha R, López CA, Tran TH, Oppelstrup T, Bhatia H, Stanton LG, Zhang X, Sundram S, Di Natale F, Agarwal A, Dharuman G, Kokkila Schumacher SIL, Turbyville T, Gulten G, Van QN, Goswami D, Jean-Francois F, Agamasu C, Chen D, Hettige JJ, Travers T, Sarkar S, Surh MP, Yang Y, Moody A, Liu S, Van Essen BC, Voter AF, Ramanathan A, Hengartner NW, Simanshu DK, Stephen AG, Bremer PT, Gnanakaran S, Glosli JN, Lightstone FC, McCormick F, Nissley DV, Streitz FH. Machine learning-driven multiscale modeling reveals lipid-dependent dynamics of RAS signaling proteins. Proc Natl Acad Sci U S A 2022; 119:e2113297119. [PMID: 34983849 PMCID: PMC8740753 DOI: 10.1073/pnas.2113297119] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/24/2021] [Indexed: 01/17/2023] Open
Abstract
RAS is a signaling protein associated with the cell membrane that is mutated in up to 30% of human cancers. RAS signaling has been proposed to be regulated by dynamic heterogeneity of the cell membrane. Investigating such a mechanism requires near-atomistic detail at macroscopic temporal and spatial scales, which is not possible with conventional computational or experimental techniques. We demonstrate here a multiscale simulation infrastructure that uses machine learning to create a scale-bridging ensemble of over 100,000 simulations of active wild-type KRAS on a complex, asymmetric membrane. Initialized and validated with experimental data (including a new structure of active wild-type KRAS), these simulations represent a substantial advance in the ability to characterize RAS-membrane biology. We report distinctive patterns of local lipid composition that correlate with interfacially promiscuous RAS multimerization. These lipid fingerprints are coupled to RAS dynamics, predicted to influence effector binding, and therefore may be a mechanism for regulating cell signaling cascades.
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Affiliation(s)
- Helgi I Ingólfsson
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550
| | - Chris Neale
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, NM 87545
| | - Timothy S Carpenter
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550
| | - Rebika Shrestha
- RAS Initiative, The Cancer Research Technology Program, Frederick National Laboratory, Frederick, MD 21701
| | - Cesar A López
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, NM 87545
| | - Timothy H Tran
- RAS Initiative, The Cancer Research Technology Program, Frederick National Laboratory, Frederick, MD 21701
| | - Tomas Oppelstrup
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550
| | - Harsh Bhatia
- Computing Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550
| | - Liam G Stanton
- Department of Mathematics and Statistics, San José State University, San José, CA 95192
| | - Xiaohua Zhang
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550
| | - Shiv Sundram
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550
| | - Francesco Di Natale
- Computing Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550
| | - Animesh Agarwal
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, NM 87545
| | - Gautham Dharuman
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550
| | | | - Thomas Turbyville
- RAS Initiative, The Cancer Research Technology Program, Frederick National Laboratory, Frederick, MD 21701
| | - Gulcin Gulten
- RAS Initiative, The Cancer Research Technology Program, Frederick National Laboratory, Frederick, MD 21701
| | - Que N Van
- RAS Initiative, The Cancer Research Technology Program, Frederick National Laboratory, Frederick, MD 21701
| | - Debanjan Goswami
- RAS Initiative, The Cancer Research Technology Program, Frederick National Laboratory, Frederick, MD 21701
| | - Frantz Jean-Francois
- RAS Initiative, The Cancer Research Technology Program, Frederick National Laboratory, Frederick, MD 21701
| | - Constance Agamasu
- RAS Initiative, The Cancer Research Technology Program, Frederick National Laboratory, Frederick, MD 21701
| | - De Chen
- RAS Initiative, The Cancer Research Technology Program, Frederick National Laboratory, Frederick, MD 21701
| | - Jeevapani J Hettige
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, NM 87545
| | - Timothy Travers
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, NM 87545
| | - Sumantra Sarkar
- Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, NM 87545
| | - Michael P Surh
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550
| | - Yue Yang
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550
| | - Adam Moody
- Computing Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550
| | - Shusen Liu
- Computing Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550
| | - Brian C Van Essen
- Computing Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550
| | - Arthur F Voter
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545
| | - Arvind Ramanathan
- Computing, Environment & Life Sciences Directorate, Argonne National Laboratory, Lemont, IL 60439
| | - Nicolas W Hengartner
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, NM 87545
| | - Dhirendra K Simanshu
- RAS Initiative, The Cancer Research Technology Program, Frederick National Laboratory, Frederick, MD 21701
| | - Andrew G Stephen
- RAS Initiative, The Cancer Research Technology Program, Frederick National Laboratory, Frederick, MD 21701
| | - Peer-Timo Bremer
- Computing Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550
| | - S Gnanakaran
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, NM 87545
| | - James N Glosli
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550
| | - Felice C Lightstone
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550
| | - Frank McCormick
- RAS Initiative, The Cancer Research Technology Program, Frederick National Laboratory, Frederick, MD 21701;
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA 94115
| | - Dwight V Nissley
- RAS Initiative, The Cancer Research Technology Program, Frederick National Laboratory, Frederick, MD 21701;
| | - Frederick H Streitz
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550;
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26
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Ilter M, Kasmer R, Jalalypour F, Atilgan C, Topcu O, Karakas N, Sensoy O. Inhibition of mutant RAS-RAF interaction by mimicking structural and dynamic properties of phosphorylated RAS. eLife 2022; 11:79747. [PMID: 36458814 PMCID: PMC9762712 DOI: 10.7554/elife.79747] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 11/30/2022] [Indexed: 12/03/2022] Open
Abstract
Undruggability of RAS proteins has necessitated alternative strategies for the development of effective inhibitors. In this respect, phosphorylation has recently come into prominence as this reversible post-translational modification attenuates sensitivity of RAS towards RAF. As such, in this study, we set out to unveil the impact of phosphorylation on dynamics of HRASWT and aim to invoke similar behavior in HRASG12D mutant by means of small therapeutic molecules. To this end, we performed molecular dynamics (MD) simulations using phosphorylated HRAS and showed that phosphorylation of Y32 distorted Switch I, hence the RAS/RAF interface. Consequently, we targeted Switch I in HRASG12D by means of approved therapeutic molecules and showed that the ligands enabled detachment of Switch I from the nucleotide-binding pocket. Moreover, we demonstrated that displacement of Switch I from the nucleotide-binding pocket was energetically more favorable in the presence of the ligand. Importantly, we verified computational findings in vitro where HRASG12D/RAF interaction was prevented by the ligand in HEK293T cells that expressed HRASG12D mutant protein. Therefore, these findings suggest that targeting Switch I, hence making Y32 accessible might open up new avenues in future drug discovery strategies that target mutant RAS proteins.
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Affiliation(s)
- Metehan Ilter
- Graduate School of Engineering and Natural Sciences, Istanbul Medipol UniversityIstanbulTurkey
| | - Ramazan Kasmer
- Medical Biology and Genetics Program, Graduate School for Health Sciences, Istanbul Medipol UniversityIstanbulTurkey,Cancer Research Center, Institute for Health Sciences and Technologies (SABITA), Istanbul Medipol UniversityIstanbulTurkey
| | - Farzaneh Jalalypour
- Faculty of Engineering and Natural Sciences, Sabanci UniversityIstanbulTurkey
| | - Canan Atilgan
- Faculty of Engineering and Natural Sciences, Sabanci UniversityIstanbulTurkey
| | - Ozan Topcu
- Medical Biology and Genetics Program, Graduate School for Health Sciences, Istanbul Medipol UniversityIstanbulTurkey
| | - Nihal Karakas
- Medical Biology and Genetics Program, Graduate School for Health Sciences, Istanbul Medipol UniversityIstanbulTurkey,Department of Medical Biology, International School of Medicine, Istanbul Medipol UniversityIstanbulTurkey
| | - Ozge Sensoy
- Department of Computer Engineering, School of Engineering and Natural Sciences, Istanbul Medipol UniversityIstanbulTurkey,Regenerative and Restorative Medicine Research Center (REMER), Institute for Health Sciences and Technologies (SABITA), Istanbul Medipol UniversityIstanbulTurkey
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27
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Zhang M, Maloney R, Jang H, Nussinov R. The mechanism of Raf activation through dimerization. Chem Sci 2021; 12:15609-15619. [PMID: 35003591 PMCID: PMC8654025 DOI: 10.1039/d1sc03444h] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 11/16/2021] [Indexed: 01/07/2023] Open
Abstract
Raf, a threonine/serine kinase in the Raf/MEK/ERK pathway, regulates cell proliferation. Raf's full activation requires dimerization. Aberrant activation through dimerization is an important therapeutic target. Despite its clinical importance, fundamental questions, such as how the side-to-side dimerization promotes the OFF-to-ON transition of Raf's kinase domain and how the fully activated ON-state kinase domain is stabilized in the dimer for Raf signaling, remain unanswered. Herein, we decipher an atomic-level mechanism of Raf activation through dimerization, clarifying this enigma. The mechanism reveals that the replacement of intramolecular π–π stacking by intermolecular π–π stacking at the dimer interface releases the structural constraint of the αC-helix, promoting the OFF-to-ON transition. During the transition, the inhibitory hydrophobic interactions were disrupted, making the phosphorylation sites in A-loop approach the HRD motif for cis-autophosphorylation. Once fully activated, the ON-state kinase domain can be stabilized by a newly identified functional N-terminal basic (NtB) motif in the dimer for Raf signaling. This work provides atomic level insight into critical steps in Raf activation and outlines a new venue for drug discovery against Raf dimerization. We decipher an atomic-level mechanism of Raf activation through dimerization, revealing that the disruption of intramolecular π–π stacking at the dimer interface promotes the OFF-to-ON transition.![]()
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Affiliation(s)
- Mingzhen Zhang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute Frederick MD 21702 USA +1-301-846-5579
| | - Ryan Maloney
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute Frederick MD 21702 USA +1-301-846-5579
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute Frederick MD 21702 USA +1-301-846-5579
| | - Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute Frederick MD 21702 USA +1-301-846-5579.,Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University Tel Aviv 69978 Israel
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28
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Lee KY, Enomoto M, Gebregiworgis T, Gasmi-Seabrook GMC, Ikura M, Marshall CB. Oncogenic KRAS G12D mutation promotes dimerization through a second, phosphatidylserine-dependent interface: a model for KRAS oligomerization. Chem Sci 2021; 12:12827-12837. [PMID: 34703570 PMCID: PMC8494122 DOI: 10.1039/d1sc03484g] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 09/04/2021] [Indexed: 12/02/2022] Open
Abstract
KRAS forms transient dimers and higher-order multimers (nanoclusters) on the plasma membrane, which drive MAPK signaling and cell proliferation. KRAS is a frequently mutated oncogene, and while it is well known that the most prevalent mutation, G12D, impairs GTP hydrolysis, thereby increasing KRAS activation, G12D has also been shown to enhance nanoclustering. Elucidating structures of dynamic KRAS assemblies on a membrane has been challenging, thus we have refined our NMR approach that uses nanodiscs to study KRAS associated with membranes. We incorporated paramagnetic relaxation enhancement (PRE) titrations and interface mutagenesis, which revealed that, in addition to the symmetric ‘α–α’ dimerization interface shared with wild-type KRAS, the G12D mutant also self-associates through an asymmetric ‘α–β’ interface. The ‘α–β’ association is dependent on the presence of phosphatidylserine lipids, consistent with previous reports that this lipid promotes KRAS self-assembly on the plasma membrane in cells. Experiments using engineered mutants to spoil each interface, together with PRE probes attached to the membrane or free in solvent, suggest that dimerization through the primary ‘α–α’ interface releases β interfaces from the membrane promoting formation of the secondary ‘α–β’ interaction, potentially initiating nanoclustering. In addition, the small molecule BI-2852 binds at a β–β interface, stabilizing a new dimer configuration that outcompetes native dimerization and blocks the effector-binding site. Our data indicate that KRAS self-association involves a delicately balanced conformational equilibrium between transient states, which is sensitive to disease-associated mutation and small molecule inhibitors. The methods developed here are applicable to biologically important transient interactions involving other membrane-associated proteins. Studies of membrane-dependent dimerization of KRAS on nanodiscs using paramagnetic NMR titrations and mutagenesis revealed a novel asymmetric ‘α–β’ interface that provides a potential mechanism for the enhanced assembly of KRAS–G12D nanoclusters.![]()
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Affiliation(s)
- Ki-Young Lee
- Princess Margaret Cancer Centre, University Health Network Toronto Ontario M5G 1L7 Canada
| | - Masahiro Enomoto
- Princess Margaret Cancer Centre, University Health Network Toronto Ontario M5G 1L7 Canada
| | - Teklab Gebregiworgis
- Princess Margaret Cancer Centre, University Health Network Toronto Ontario M5G 1L7 Canada
| | | | - Mitsuhiko Ikura
- Princess Margaret Cancer Centre, University Health Network Toronto Ontario M5G 1L7 Canada .,Department of Medical Biophysics, University of Toronto Toronto Ontario M5G 1L7 Canada
| | - Christopher B Marshall
- Princess Margaret Cancer Centre, University Health Network Toronto Ontario M5G 1L7 Canada
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29
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Nussinov R, Zhang M, Maloney R, Jang H. Ras isoform-specific expression, chromatin accessibility, and signaling. Biophys Rev 2021; 13:489-505. [PMID: 34466166 PMCID: PMC8355297 DOI: 10.1007/s12551-021-00817-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 06/29/2021] [Indexed: 12/12/2022] Open
Abstract
The anchorage of Ras isoforms in the membrane and their nanocluster formations have been studied extensively, including their detailed interactions, sizes, preferred membrane environments, chemistry, and geometry. However, the staggering challenge of their epigenetics and chromatin accessibility in distinct cell states and types, which we propose is a major factor determining their specific expression, still awaits unraveling. Ras isoforms are distinguished by their C-terminal hypervariable region (HVR) which acts in intracellular transport, regulation, and membrane anchorage. Here, we review some isoform-specific activities at the plasma membrane from a structural dynamic standpoint. Inspired by physics and chemistry, we recognize that understanding functional specificity requires insight into how biomolecules can organize themselves in different cellular environments. Within this framework, we suggest that isoform-specific expression may largely be controlled by the chromatin density and physical compaction, which allow (or curb) access to "chromatinized DNA." Genes are preferentially expressed in tissues: proteins expressed in pancreatic cells may not be equally expressed in lung cells. It is the rule-not an exception, and it can be at least partly understood in terms of chromatin organization and accessibility state. Genes are expressed when they can be sufficiently exposed to the transcription machinery, and they are less so when they are persistently buried in dense chromatin. Notably, chromatin accessibility can similarly determine expression of drug resistance genes.
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Affiliation(s)
- Ruth Nussinov
- Computational Structural Biology Section Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism National Cancer Institute, 1050 Boyles St, Frederick, MD 21702 USA
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine Tel Aviv University, 69978 Tel Aviv, Israel
| | - Mingzhen Zhang
- Computational Structural Biology Section Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism National Cancer Institute, 1050 Boyles St, Frederick, MD 21702 USA
| | - Ryan Maloney
- Computational Structural Biology Section Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism National Cancer Institute, 1050 Boyles St, Frederick, MD 21702 USA
| | - Hyunbum Jang
- Computational Structural Biology Section Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism National Cancer Institute, 1050 Boyles St, Frederick, MD 21702 USA
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30
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Cookis T, Mattos C. Crystal Structure Reveals the Full Ras-Raf Interface and Advances Mechanistic Understanding of Raf Activation. Biomolecules 2021; 11:996. [PMID: 34356620 PMCID: PMC8301913 DOI: 10.3390/biom11070996] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 07/01/2021] [Accepted: 07/02/2021] [Indexed: 01/17/2023] Open
Abstract
Ras and Raf-kinase interact through the Ras-binding (RBD) and cysteine-rich domains (CRD) of Raf to signal through the mitogen-activated protein kinase pathway, yet the molecular mechanism leading to Raf activation has remained elusive. We present the 2.8 Å crystal structure of the HRas-CRaf-RBD_CRD complex showing the Ras-Raf interface as a continuous surface on Ras, as seen in the KRas-CRaf-RBD_CRD structure. In molecular dynamics simulations of a Ras dimer model formed through the α4-α5 interface, the CRD is dynamic and located between the two Ras protomers, poised for direct or allosteric modulation of functionally relevant regions of Ras and Raf. We propose a molecular model in which Ras binding is involved in the release of Raf autoinhibition while the Ras-Raf complex dimerizes to promote a platform for signal amplification, with Raf-CRD centrally located to impact regulation and function.
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Affiliation(s)
| | - Carla Mattos
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA;
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31
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Zhang M, Jang H, Li Z, Sacks DB, Nussinov R. B-Raf autoinhibition in the presence and absence of 14-3-3. Structure 2021; 29:768-777.e2. [PMID: 33711246 PMCID: PMC9907365 DOI: 10.1016/j.str.2021.02.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 02/04/2021] [Accepted: 02/19/2021] [Indexed: 01/06/2023]
Abstract
Raf-activating mutations are frequent in cancer. In the basal state, B-Raf is autoinhibited by its upstream Ras-binding domain (RBD) and cysteine-rich domain (RBD-CRD) interacting with its kinase domain (KD) and the 14-3-3 dimer. Our comprehensive molecular dynamics simulations explore two autoinhibition scenarios in the presence and absence of the 14-3-3 dimer. When present, the 14-3-3 interaction with B-Raf stabilizes the RBD-CRD-KD interaction, interfering with the KD dimerization. Raf's pSer365 removal fails to induce large disruption. RBD-CRD release promotes KD fluctuations and reorientation for dimerization, consistent with experimental data. In the absence of 14-3-3, our sampled B-Raf conformations suggest that RBD-CRD can block the KD dimerization surface. Our results suggest a B-Raf activation mechanism, whereby one KD monomer is donated by 14-3-3-free B-Raf KD and the other by 14-3-3-bound KD. This mechanism can lead to homo- and heterodimers. These autoinhibition scenarios can transform autoinhibited B-Raf monomers into active B-Raf dimers.
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Affiliation(s)
- Mingzhen Zhang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer ImmunoMetabolism, National Cancer Institute, Frederick, MD 21702, USA
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer ImmunoMetabolism, National Cancer Institute, Frederick, MD 21702, USA
| | - Zhigang Li
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, MD 20892, USA
| | - David B Sacks
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer ImmunoMetabolism, National Cancer Institute, Frederick, MD 21702, USA; Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel.
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32
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Maloney RC, Zhang M, Jang H, Nussinov R. The mechanism of activation of monomeric B-Raf V600E. Comput Struct Biotechnol J 2021; 19:3349-3363. [PMID: 34188782 PMCID: PMC8215184 DOI: 10.1016/j.csbj.2021.06.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 05/30/2021] [Accepted: 06/02/2021] [Indexed: 02/07/2023] Open
Abstract
Oncogenic mutations in the serine/threonine kinase B-Raf, particularly the V600E mutation, are frequent in cancer, making it a major drug target. Although much is known about B-Raf's active and inactive states, questions remain about the mechanism by which the protein changes between these two states. Here, we utilize molecular dynamics to investigate both wild-type and V600E B-Raf to gain mechanistic insights into the impact of the Val to Glu mutation. The results show that the wild-type and mutant follow similar activation pathways involving an extension of the activation loop and an inward motion of the αC-helix. The V600E mutation, however, destabilizes the inactive state by disrupting hydrophobic interactions present in the wild-type structure while the active state is stabilized through the formation of a salt bridge between Glu600 and Lys507. Additionally, when the activation loop is extended, the αC-helix is able to move between an inward and outward orientation as long as the DFG motif adopts a specific orientation. In that orientation Phe595 rotates away from the αC-helix, allowing the formation of a salt bridge between Lys483 and Glu501. These mechanistic insights have implications for the development of new Raf inhibitors.
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Affiliation(s)
- Ryan C. Maloney
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA
| | - Mingzhen Zhang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA
| | - Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
- Corresponding author at: Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA.
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33
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Rezaei Adariani S, Kazemein Jasemi NS, Bazgir F, Wittich C, Amin E, Seidel CAM, Dvorsky R, Ahmadian MR. A comprehensive analysis of RAS-effector interactions reveals interaction hotspots and new binding partners. J Biol Chem 2021; 296:100626. [PMID: 33930461 PMCID: PMC8163975 DOI: 10.1016/j.jbc.2021.100626] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 03/25/2021] [Accepted: 03/31/2021] [Indexed: 02/07/2023] Open
Abstract
RAS effectors specifically interact with GTP-bound RAS proteins to link extracellular signals to downstream signaling pathways. These interactions rely on two types of domains, called RAS-binding (RB) and RAS association (RA) domains, which share common structural characteristics. Although the molecular nature of RAS-effector interactions is well-studied for some proteins, most of the RA/RB-domain-containing proteins remain largely uncharacterized. Here, we searched through human proteome databases, extracting 41 RA domains in 39 proteins and 16 RB domains in 14 proteins, each of which can specifically select at least one of the 25 members in the RAS family. We next comprehensively investigated the sequence–structure–function relationship between different representatives of the RAS family, including HRAS, RRAS, RALA, RAP1B, RAP2A, RHEB1, and RIT1, with all members of RA domain family proteins (RASSFs) and the RB-domain-containing CRAF. The binding affinity for RAS-effector interactions, determined using fluorescence polarization, broadly ranged between high (0.3 μM) and very low (500 μM) affinities, raising interesting questions about the consequence of these variable binding affinities in the regulation of signaling events. Sequence and structural alignments pointed to two interaction hotspots in the RA/RB domains, consisting of an average of 19 RAS-binding residues. Moreover, we found novel interactions between RRAS1, RIT1, and RALA and RASSF7, RASSF9, and RASSF1, respectively, which were systematically explored in sequence–structure–property relationship analysis, and validated by mutational analysis. These data provide a set of distinct functional properties and putative biological roles that should now be investigated in the cellular context.
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Affiliation(s)
- Soheila Rezaei Adariani
- Medical Faculty, Institute of Biochemistry and Molecular Biology II, Heinrich Heine University, Düsseldorf, Germany
| | - Neda S Kazemein Jasemi
- Medical Faculty, Institute of Biochemistry and Molecular Biology II, Heinrich Heine University, Düsseldorf, Germany
| | - Farhad Bazgir
- Medical Faculty, Institute of Biochemistry and Molecular Biology II, Heinrich Heine University, Düsseldorf, Germany
| | - Christoph Wittich
- Medical Faculty, Institute of Biochemistry and Molecular Biology II, Heinrich Heine University, Düsseldorf, Germany
| | - Ehsan Amin
- Medical Faculty, Institute of Biochemistry and Molecular Biology II, Heinrich Heine University, Düsseldorf, Germany; Medical Faculty, Institute of Neural and Sensory Physiology, Heinrich Heine University, Düsseldorf, Germany
| | - Claus A M Seidel
- Chair of Molecular Physical Chemistry, Heinrich Heine University, Düsseldorf, Germany
| | - Radovan Dvorsky
- Medical Faculty, Institute of Biochemistry and Molecular Biology II, Heinrich Heine University, Düsseldorf, Germany
| | - Mohammad R Ahmadian
- Medical Faculty, Institute of Biochemistry and Molecular Biology II, Heinrich Heine University, Düsseldorf, Germany.
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34
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López CA, Agarwal A, Van QN, Stephen AG, Gnanakaran S. Unveiling the Dynamics of KRAS4b on Lipid Model Membranes. J Membr Biol 2021; 254:201-216. [PMID: 33825026 PMCID: PMC8052243 DOI: 10.1007/s00232-021-00176-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 03/16/2021] [Indexed: 12/23/2022]
Abstract
Small GTPase proteins are ubiquitous and responsible for regulating several processes related to cell growth and differentiation. Mutations that stabilize their active state can lead to uncontrolled cell proliferation and cancer. Although these proteins are well characterized at the cellular scale, the molecular mechanisms governing their functions are still poorly understood. In addition, there is limited information about the regulatory function of the cell membrane which supports their activity. Thus, we have studied the dynamics and conformations of the farnesylated KRAS4b in various membrane model systems, ranging from binary fluid mixtures to heterogeneous raft mimics. Our approach combines long time-scale coarse-grained (CG) simulations and Markov state models to dissect the membrane-supported dynamics of KRAS4b. Our simulations reveal that protein dynamics is mainly modulated by the presence of anionic lipids and to some extent by the nucleotide state (activation) of the protein. In addition, our results suggest that both the farnesyl and the polybasic hypervariable region (HVR) are responsible for its preferential partitioning within the liquid-disordered (Ld) domains in membranes, potentially enhancing the formation of membrane-driven signaling platforms.
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Affiliation(s)
- Cesar A López
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA.
| | - Animesh Agarwal
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Que N Van
- National Cancer Institute RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, MD, 21702, USA
| | - Andrew G Stephen
- National Cancer Institute RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, MD, 21702, USA
| | - S Gnanakaran
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
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35
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Cook FA, Cook SJ. Inhibition of RAF dimers: it takes two to tango. Biochem Soc Trans 2021; 49:237-251. [PMID: 33367512 PMCID: PMC7924995 DOI: 10.1042/bst20200485] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 11/17/2020] [Accepted: 11/23/2020] [Indexed: 02/07/2023]
Abstract
The RAS-regulated RAF-MEK1/2-ERK1/2 pathway promotes cell proliferation and survival and RAS and BRAF proteins are commonly mutated in cancer. This has fuelled the development of small molecule kinase inhibitors including ATP-competitive RAF inhibitors. Type I and type I½ ATP-competitive RAF inhibitors are effective in BRAFV600E/K-mutant cancer cells. However, in RAS-mutant cells these compounds instead promote RAS-dependent dimerisation and paradoxical activation of wild-type RAF proteins. RAF dimerisation is mediated by two key regions within each RAF protein; the RKTR motif of the αC-helix and the NtA-region of the dimer partner. Dimer formation requires the adoption of a closed, active kinase conformation which can be induced by RAS-dependent activation of RAF or by the binding of type I and I½ RAF inhibitors. Binding of type I or I½ RAF inhibitors to one dimer partner reduces the binding affinity of the other, thereby leaving a single dimer partner uninhibited and able to activate MEK. To overcome this paradox two classes of drug are currently under development; type II pan-RAF inhibitors that induce RAF dimer formation but bind both dimer partners thus allowing effective inhibition of both wild-type RAF dimer partners and monomeric active class I mutant RAF, and the recently developed "paradox breakers" which interrupt BRAF dimerisation through disruption of the αC-helix. Here we review the regulation of RAF proteins, including RAF dimers, and the progress towards effective targeting of the wild-type RAF proteins.
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Affiliation(s)
- Frazer A. Cook
- Signalling Programme, The Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, U.K
| | - Simon J. Cook
- Signalling Programme, The Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, U.K
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36
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Lim S, Khoo R, Juang YC, Gopal P, Zhang H, Yeo C, Peh KM, Teo J, Ng S, Henry B, Partridge AW. Exquisitely Specific anti-KRAS Biodegraders Inform on the Cellular Prevalence of Nucleotide-Loaded States. ACS CENTRAL SCIENCE 2021; 7:274-291. [PMID: 33655066 PMCID: PMC7908030 DOI: 10.1021/acscentsci.0c01337] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Indexed: 05/05/2023]
Abstract
Mutations to RAS proteins (H-, N-, and K-RAS) are among the most common oncogenic drivers, and tumors harboring these lesions are some of the most difficult to treat. Although covalent small molecules against KRASG12C have shown promising efficacy against lung cancers, traditional barriers remain for drugging the more prevalent KRASG12D and KRASG12V mutants. Targeted degradation has emerged as an attractive alternative approach, but for KRAS, identification of the required high-affinity ligands continues to be a challenge. Another significant hurdle is the discovery of a hybrid molecule that appends an E3 ligase-recruiting moiety in a manner that satisfies the precise geometries required for productive polyubiquitin transfer while maintaining favorable druglike properties. To gain insights into the advantages and feasibility of KRAS targeted degradation, we applied a protein-based degrader (biodegrader) approach. This workflow centers on the intracellular expression of a chimeric protein consisting of a high-affinity target-binding domain fused to an engineered E3 ligase adapter. A series of anti-RAS biodegraders spanning different RAS isoform/nucleotide-state specificities and leveraging different E3 ligases provided definitive evidence for RAS degradability. Further, these established that the functional consequences of KRAS degradation are context dependent. Of broader significance, using the exquisite degradation specificity that biodegraders can possess, we demonstrated how this technology can be applied to answer questions that other approaches cannot. Specifically, application of the GDP-state specific degrader uncovered the relative prevalence of the "off-state" of WT and various KRAS mutants in the cellular context. Finally, if delivery challenges can be addressed, anti-RAS biodegraders will be exciting candidates for clinical development.
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37
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KRAS interaction with RAF1 RAS-binding domain and cysteine-rich domain provides insights into RAS-mediated RAF activation. Nat Commun 2021; 12:1176. [PMID: 33608534 PMCID: PMC7895934 DOI: 10.1038/s41467-021-21422-x] [Citation(s) in RCA: 99] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 01/26/2021] [Indexed: 12/12/2022] Open
Abstract
The first step of RAF activation involves binding to active RAS, resulting in the recruitment of RAF to the plasma membrane. To understand the molecular details of RAS-RAF interaction, we present crystal structures of wild-type and oncogenic mutants of KRAS complexed with the RAS-binding domain (RBD) and the membrane-interacting cysteine-rich domain (CRD) from the N-terminal regulatory region of RAF1. Our structures reveal that RBD and CRD interact with each other to form one structural entity in which both RBD and CRD interact extensively with KRAS. Mutations at the KRAS-CRD interface result in a significant reduction in RAF1 activation despite only a modest decrease in binding affinity. Combining our structures and published data, we provide a model of RAS-RAF complexation at the membrane, and molecular insights into RAS-RAF interaction during the process of RAS-mediated RAF activation. The molecular details of the RAS-RAF interaction are still not fully understood. Here, the authors present crystal structures of wild-type and mutant KRAS in complex with the RAS-binding and membrane-interacting cysteine-rich domains of RAF1, and propose a model of the membrane-bound RAS-RAF complex.
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38
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Nussinov R, Jang H, Gursoy A, Keskin O, Gaponenko V. Inhibition of Nonfunctional Ras. Cell Chem Biol 2021; 28:121-133. [PMID: 33440168 PMCID: PMC7897307 DOI: 10.1016/j.chembiol.2020.12.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 10/28/2020] [Accepted: 12/21/2020] [Indexed: 02/07/2023]
Abstract
Intuitively, functional states should be targeted; not nonfunctional ones. So why could drugging the inactive K-Ras4BG12Cwork-but drugging the inactive kinase will likely not? The reason is the distinct oncogenic mechanisms. Kinase driver mutations work by stabilizing the active state and/or destabilizing the inactive state. Either way, oncogenic kinases are mostly in the active state. Ras driver mutations work by quelling its deactivation mechanisms, GTP hydrolysis, and nucleotide exchange. Covalent inhibitors that bind to the inactive GDP-bound K-Ras4BG12C conformation can thus work. By contrast, in kinases, allosteric inhibitors work by altering the active-site conformation to favor orthosteric drugs. From the translational standpoint this distinction is vital: it expedites effective pharmaceutical development and extends the drug classification based on the mechanism of action. Collectively, here we postulate that drug action relates to blocking the mechanism of activation, not to whether the protein is in the active or inactive state.
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Affiliation(s)
- Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA; Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel.
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA
| | - Attila Gursoy
- Department of Computer Engineering, Koc University, Istanbul 34450, Turkey
| | - Ozlem Keskin
- Department of Chemical and Biological Engineering, Koc University, Istanbul 34450, Turkey
| | - Vadim Gaponenko
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, IL 60607, USA.
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39
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Kiel C, Matallanas D, Kolch W. The Ins and Outs of RAS Effector Complexes. Biomolecules 2021; 11:236. [PMID: 33562401 PMCID: PMC7915224 DOI: 10.3390/biom11020236] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Revised: 01/31/2021] [Accepted: 02/03/2021] [Indexed: 12/12/2022] Open
Abstract
RAS oncogenes are among the most commonly mutated proteins in human cancers. They regulate a wide range of effector pathways that control cell proliferation, survival, differentiation, migration and metabolic status. Including aberrations in these pathways, RAS-dependent signaling is altered in more than half of human cancers. Targeting mutant RAS proteins and their downstream oncogenic signaling pathways has been elusive. However, recent results comprising detailed molecular studies, large scale omics studies and computational modeling have painted a new and more comprehensive portrait of RAS signaling that helps us to understand the intricacies of RAS, how its physiological and pathophysiological functions are regulated, and how we can target them. Here, we review these efforts particularly trying to relate the detailed mechanistic studies with global functional studies. We highlight the importance of computational modeling and data integration to derive an actionable understanding of RAS signaling that will allow us to design new mechanism-based therapies for RAS mutated cancers.
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Affiliation(s)
- Christina Kiel
- Systems Biology Ireland, School of Medicine, University College Dublin, Dublin 4, Ireland; (C.K.); (D.M.)
- UCD Charles Institute of Dermatology, School of Medicine, University College Dublin, Dublin 4, Ireland
| | - David Matallanas
- Systems Biology Ireland, School of Medicine, University College Dublin, Dublin 4, Ireland; (C.K.); (D.M.)
| | - Walter Kolch
- Systems Biology Ireland, School of Medicine, University College Dublin, Dublin 4, Ireland; (C.K.); (D.M.)
- Conway Institute of Biomolecular & Biomedical Research, University College Dublin, Dublin 4, Ireland
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40
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Zhang M, Jang H, Nussinov R. PI3K Driver Mutations: A Biophysical Membrane-Centric Perspective. Cancer Res 2021; 81:237-247. [PMID: 33046444 PMCID: PMC7855922 DOI: 10.1158/0008-5472.can-20-0911] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 07/24/2020] [Accepted: 10/07/2020] [Indexed: 11/16/2022]
Abstract
Ras activates its effectors at the membrane. Active PI3Kα and its associated kinases/phosphatases assemble at membrane regions enriched in signaling lipids. In contrast, the Raf kinase domain extends into the cytoplasm and its assembly is away from the crowded membrane surface. Our structural membrane-centric outlook underscores the spatiotemporal principles of membrane and signaling lipids, which helps clarify PI3Kα activation. Here we focus on mechanisms of activation driven by PI3Kα driver mutations, spotlighting the PI3Kα double (multiple) activating mutations. Single mutations can be potent, but double mutations are stronger: their combination is specific, a single strong driver cannot fully activate PI3K, and two weak drivers may or may not do so. In contrast, two strong drivers may successfully activate PI3K, where one, for example, H1047R, modulates membrane interactions facilitating substrate binding at the active site (km) and the other, for example, E542K and E545K, reduces the transition state barrier (ka), releasing autoinhibition by nSH2. Although mostly unidentified, weak drivers are expected to be common, so we ask here how common double mutations are likely to be and why PI3Kα with double mutations responds effectively to inhibitors. We provide a structural view of hotspot and weak driver mutations in PI3Kα activation, explain their mechanisms, compare these with mechanisms of Raf activation, and point to targeting cell-specific, chromatin-accessible, and parallel (or redundant) pathways to thwart the expected emergence of drug resistance. Collectively, our biophysical outlook delineates activation and highlights the challenges of drug resistance.
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Affiliation(s)
- Mingzhen Zhang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, Maryland
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, Maryland
| | - Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, Maryland.
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
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41
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Abankwa D, Gorfe AA. Mechanisms of Ras Membrane Organization and Signaling: Ras Rocks Again. Biomolecules 2020; 10:E1522. [PMID: 33172116 PMCID: PMC7694788 DOI: 10.3390/biom10111522] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 11/03/2020] [Accepted: 11/04/2020] [Indexed: 12/17/2022] Open
Abstract
Ras is the most frequently mutated oncogene and recent drug development efforts have spurred significant new research interest. Here we review progress toward understanding how Ras functions in nanoscale, proteo-lipid signaling complexes on the plasma membrane, called nanoclusters. We discuss how G-domain reorientation is plausibly linked to Ras-nanoclustering and -dimerization. We then look at how these mechanistic features could cooperate in the engagement and activation of RAF by Ras. Moreover, we show how this structural information can be integrated with microscopy data that provide nanoscale resolution in cell biological experiments. Synthesizing the available data, we propose to distinguish between two types of Ras nanoclusters, an active, immobile RAF-dependent type and an inactive/neutral membrane anchor-dependent. We conclude that it is possible that Ras reorientation enables dynamic Ras dimerization while the whole Ras/RAF complex transits into an active state. These transient di/oligomer interfaces of Ras may be amenable to pharmacological intervention. We close by highlighting a number of open questions including whether all effectors form active nanoclusters and whether there is an isoform specific composition of Ras nanocluster.
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Affiliation(s)
- Daniel Abankwa
- Cancer Cell Biology and Drug Discovery Group, Department of Life Sciences and Medicine, University of Luxembourg, Esch-sur-Alzette 4362, Luxembourg
| | - Alemayehu A. Gorfe
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center at Houston, 6431 Fannin St., Houston, TX 77030, USA
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42
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Marshall CB, KleinJan F, Gebregiworgis T, Lee KY, Fang Z, Eves BJ, Liu NF, Gasmi-Seabrook GMC, Enomoto M, Ikura M. NMR in integrated biophysical drug discovery for RAS: past, present, and future. JOURNAL OF BIOMOLECULAR NMR 2020; 74:531-554. [PMID: 32804298 DOI: 10.1007/s10858-020-00338-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Accepted: 07/16/2020] [Indexed: 06/11/2023]
Abstract
Mutations in RAS oncogenes occur in ~ 30% of human cancers, with KRAS being the most frequently altered isoform. RAS proteins comprise a conserved GTPase domain and a C-terminal lipid-modified tail that is unique to each isoform. The GTPase domain is a 'switch' that regulates multiple signaling cascades that drive cell growth and proliferation when activated by binding GTP, and the signal is terminated by GTP hydrolysis. Oncogenic RAS mutations disrupt the GTPase cycle, leading to accumulation of the activated GTP-bound state and promoting proliferation. RAS is a key target in oncology, however it lacks classic druggable pockets and has been extremely challenging to target. RAS signaling has thus been targeted indirectly, by harnessing key downstream effectors as well as upstream regulators, or disrupting the proper membrane localization required for signaling, by inhibiting either lipid modification or 'carrier' proteins. As a small (20 kDa) protein with multiple conformers in dynamic equilibrium, RAS is an excellent candidate for NMR-driven characterization and screening for direct inhibitors. Several molecules have been discovered that bind RAS and stabilize shallow pockets through conformational selection, and recent compounds have achieved substantial improvements in affinity. NMR-derived insight into targeting the RAS-membrane interface has revealed a new strategy to enhance the potency of small molecules, while another approach has been development of peptidyl inhibitors that bind through large interfaces rather than deep pockets. Remarkable progress has been made with mutation-specific covalent inhibitors that target the thiol of a G12C mutant, and these are now in clinical trials. Here we review the history of RAS inhibitor development and highlight the utility of NMR and integrated biophysical approaches in RAS drug discovery.
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Affiliation(s)
- Christopher B Marshall
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, M5G 1L7, Canada.
| | - Fenneke KleinJan
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, M5G 1L7, Canada
| | - Teklab Gebregiworgis
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, M5G 1L7, Canada
| | - Ki-Young Lee
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, M5G 1L7, Canada
| | - Zhenhao Fang
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, M5G 1L7, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON, M5G 1L7, Canada
| | - Ben J Eves
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, M5G 1L7, Canada
| | - Ningdi F Liu
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, M5G 1L7, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON, M5G 1L7, Canada
| | | | - Masahiro Enomoto
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, M5G 1L7, Canada
| | - Mitsuhiko Ikura
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, M5G 1L7, Canada.
- Department of Medical Biophysics, University of Toronto, Toronto, ON, M5G 1L7, Canada.
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43
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Van QN, López CA, Tonelli M, Taylor T, Niu B, Stanley CB, Bhowmik D, Tran TH, Frank PH, Messing S, Alexander P, Scott D, Ye X, Drew M, Chertov O, Lösche M, Ramanathan A, Gross ML, Hengartner NW, Westler WM, Markley JL, Simanshu DK, Nissley DV, Gillette WK, Esposito D, McCormick F, Gnanakaran S, Heinrich F, Stephen AG. Uncovering a membrane-distal conformation of KRAS available to recruit RAF to the plasma membrane. Proc Natl Acad Sci U S A 2020; 117:24258-24268. [PMID: 32913056 PMCID: PMC7533834 DOI: 10.1073/pnas.2006504117] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The small GTPase KRAS is localized at the plasma membrane where it functions as a molecular switch, coupling extracellular growth factor stimulation to intracellular signaling networks. In this process, KRAS recruits effectors, such as RAF kinase, to the plasma membrane where they are activated by a series of complex molecular steps. Defining the membrane-bound state of KRAS is fundamental to understanding the activation of RAF kinase and in evaluating novel therapeutic opportunities for the inhibition of oncogenic KRAS-mediated signaling. We combined multiple biophysical measurements and computational methodologies to generate a consensus model for authentically processed, membrane-anchored KRAS. In contrast to the two membrane-proximal conformations previously reported, we identify a third significantly populated state using a combination of neutron reflectivity, fast photochemical oxidation of proteins (FPOP), and NMR. In this highly populated state, which we refer to as "membrane-distal" and estimate to comprise ∼90% of the ensemble, the G-domain does not directly contact the membrane but is tethered via its C-terminal hypervariable region and carboxymethylated farnesyl moiety, as shown by FPOP. Subsequent interaction of the RAF1 RAS binding domain with KRAS does not significantly change G-domain configurations on the membrane but affects their relative populations. Overall, our results are consistent with a directional fly-casting mechanism for KRAS, in which the membrane-distal state of the G-domain can effectively recruit RAF kinase from the cytoplasm for activation at the membrane.
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Affiliation(s)
- Que N Van
- National Cancer Institute RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, MD 21702
| | - Cesar A López
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, NM 87545
| | - Marco Tonelli
- National Magnetic Resonance Facility at Madison, Biochemistry Department, University of Wisconsin-Madison, Madison, WI 53706
| | - Troy Taylor
- National Cancer Institute RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, MD 21702
| | - Ben Niu
- National Mass Spectrometry Resource, Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130
| | - Christopher B Stanley
- Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831
| | - Debsindhu Bhowmik
- Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831
| | - Timothy H Tran
- National Cancer Institute RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, MD 21702
| | - Peter H Frank
- National Cancer Institute RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, MD 21702
| | - Simon Messing
- National Cancer Institute RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, MD 21702
| | - Patrick Alexander
- National Cancer Institute RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, MD 21702
| | - Daniel Scott
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213
| | - Xiaoying Ye
- National Cancer Institute RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, MD 21702
| | - Matt Drew
- National Cancer Institute RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, MD 21702
| | - Oleg Chertov
- National Cancer Institute RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, MD 21702
| | - Mathias Lösche
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213
- Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899
| | - Arvind Ramanathan
- Data Science and Learning Division, Argonne National Laboratory, Lemont, IL 60439
| | - Michael L Gross
- National Mass Spectrometry Resource, Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130
| | - Nicolas W Hengartner
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, NM 87545
| | - William M Westler
- National Magnetic Resonance Facility at Madison, Biochemistry Department, University of Wisconsin-Madison, Madison, WI 53706
| | - John L Markley
- National Magnetic Resonance Facility at Madison, Biochemistry Department, University of Wisconsin-Madison, Madison, WI 53706
| | - Dhirendra K Simanshu
- National Cancer Institute RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, MD 21702
| | - Dwight V Nissley
- National Cancer Institute RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, MD 21702
| | - William K Gillette
- National Cancer Institute RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, MD 21702
| | - Dominic Esposito
- National Cancer Institute RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, MD 21702
| | - Frank McCormick
- National Cancer Institute RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, MD 21702;
| | - S Gnanakaran
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, NM 87545
| | - Frank Heinrich
- Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899
| | - Andrew G Stephen
- National Cancer Institute RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, MD 21702;
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44
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Travers T, López CA, Agamasu C, Hettige JJ, Messing S, García AE, Stephen AG, Gnanakaran S. Anionic Lipids Impact RAS-Binding Site Accessibility and Membrane Binding Affinity of CRAF RBD-CRD. Biophys J 2020; 119:525-538. [PMID: 32649863 PMCID: PMC7399501 DOI: 10.1016/j.bpj.2020.06.021] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 06/12/2020] [Accepted: 06/18/2020] [Indexed: 11/25/2022] Open
Abstract
CRAF activation requires binding to membrane-anchored and active GTP-bound RAS. Whereas its RAS-binding domain (RBD) contains the main binding interface to the RAS G domain, its cysteine-rich domain (CRD) is responsible for association to anionic lipid-rich membranes. Both RAF domains are connected by a short linker, and it remains unclear if the two domains act independently or if one domain can impact the function of the other. Here, we used a combination of coarse-grained and all-atom molecular dynamics simulations of a CRAF RBD-CRD construct to investigate the dynamics of the RBD when it is tethered to CRD that is anchored to a POPC:POPS model membrane. First, we show that the RBD positioning is very dynamic with a preferential localization near the membrane surface. Next, we show that membrane-localized RBD has its RAS-binding interface mostly inaccessible because of its proximity to the membrane. Several positively charged residues in this interface were identified from simulations as important for driving RBD association to the membrane. Surface plasmon resonance (SPR) measurements confirmed that mutations of these RBD residues reduced the liposome partitioning of RBD-CRD. Last, simulations indicated that the presence of RBD near the membrane led to a local enrichment of anionic lipids that could potentially enhance the membrane affinity of the entire RBD-CRD construct. This was supported by SPR measurements that showed stronger liposome partitioning of RBD-CRD relative to CRD alone. These findings thus suggest that the RBD and CRD have synergistic effects on their membrane dynamics, with CRD bringing RBD closer to the membrane that impacts its accessibility to RAS and with RBD causing local anionic lipid enrichment that enhances the overall affinity between the membrane and RBD-CRD. These mechanisms have potential implications on the order of events of the interactions between RAS and CRAF at the membrane.
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Affiliation(s)
- Timothy Travers
- Theoretical Biology and Biophysics Group, Los Alamos, New Mexico; Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico
| | - Cesar A López
- Theoretical Biology and Biophysics Group, Los Alamos, New Mexico
| | - Constance Agamasu
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Reseach, Inc., Frederick, Maryland
| | | | - Simon Messing
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Reseach, Inc., Frederick, Maryland
| | - Angel E García
- Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico
| | - Andrew G Stephen
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Reseach, Inc., Frederick, Maryland
| | - S Gnanakaran
- Theoretical Biology and Biophysics Group, Los Alamos, New Mexico.
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45
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Ngo VA, Sarkar S, Neale C, Garcia AE. How Anionic Lipids Affect Spatiotemporal Properties of KRAS4B on Model Membranes. J Phys Chem B 2020; 124:5434-5453. [PMID: 32438809 DOI: 10.1021/acs.jpcb.0c02642] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
RAS proteins are small membrane-anchored GTPases that regulate key cellular signaling networks. It has been recently shown that different anionic lipid types can affect the spatiotemporal properties of RAS through dimerization/clustering and signaling fidelity. To understand the effects of anionic lipids on key spatiotemporal properties of RAS, we dissected 1 ms of data from all-atom molecular dynamics simulations for KRAS4B on two model anionic lipid membranes that have 30% of POPS mixed with neutral POPC and 8% of PIP2 mixed with POPC. We unveiled the orientation space of KRAS4B, whose kinetics were slower and more distinguishable on the membrane containing PIP2 than the membrane containing POPS. Particularly, the PIP2-mixed membrane can differentiate a third kinetic orientation state from the other two known orientation states. We observed that each orientation state may yield different binding modes with an RAF kinase, which is required for activating the MAPK/ERK signaling pathway. However, an overall occluded probability, for which RAF kinases cannot bind KRAS4B, remains unchanged on the two different membranes. We identified rare fast diffusion modes of KRAS4B that appear coupled with orientations exposed to cytosolic RAF. Particularly, on the membrane having PIP2, we found nonlinear correlations between the orientation states and the conformations of the cationic farnesylated hypervariable region, which acts as an anchor in the membrane. Using diffusion coefficients estimated from the all-atom simulations, we quantified the effect of PIP2 and POPS on the KRAS4B dimerization via Green's function reaction dynamics simulations, in which the averaged dimerization rate is 12.5% slower on PIP2-mixed membranes.
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Affiliation(s)
- Van A Ngo
- Center for Nonlinear Studies (CNLS), Los Alamos National Lab, Los Alamos, New Mexico 87545, United States
| | - Sumantra Sarkar
- Center for Nonlinear Studies (CNLS), Los Alamos National Lab, Los Alamos, New Mexico 87545, United States
| | - Chris Neale
- Theoretical Biology and Biophysics Group, T-6, Los Alamos National Lab, Los Alamos, New Mexico 87545, United States
| | - Angel E Garcia
- Center for Nonlinear Studies (CNLS), Los Alamos National Lab, Los Alamos, New Mexico 87545, United States
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46
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Li L, Möbitz S, Winter R. Characterization of the Spatial Organization of Raf Isoforms Interacting with K-Ras4B in the Lipid Membrane. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:5944-5953. [PMID: 32390436 DOI: 10.1021/acs.langmuir.0c00770] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Activation of Raf kinases by the membrane-anchored protein K-Ras4B is a key step of cellular signal regulation. As a predominant variant of the Ras family, K-Ras4B has been considered to be a major drug target in cancer therapy. Therefore, an integrated study of Raf interaction with membrane-associated K-Ras4B is essential. While the Ras-binding domain (RBD) of Raf contains the main binding interface to K-Ras4B, its cysteine-rich domain (CRD) is thought to be responsible for its association with the membrane interface. We applied time-lapse tapping-mode atomic force microscopy to visualize and characterize the interaction of these binding motifs of A-, B-, and C-Raf isoforms with K-Ras4B in a raft-like anionic model biomembrane. However, we found that the RBDs of the Raf isomers are readily recruited to K-Ras4B nanoclusters in the lipid membrane, with different efficiencies. Unexpectedly and different from A-Raf-RBD, B- and C-Raf-RBD are able to bind markedly also directly to the lipid membrane. We also found that Raf-RBD-CRD is readily recruited to the K-Ras4B forming nanoclusters in the fluid membrane phase, with the CRD domains binding to the lipid interface. The K-Ras4B-nanoclusters are likely to enhance Raf binding and activate signaling by enriching the Raf proteins and facilitating formation of Raf dimers. Interestingly, A-, B-, and C-Raf-RBD-CRD are also able to bind directly to the heterogeneous membrane surrounding the K-Ras4B nanoclusters, which could potentially enhance the overall affinity to K-Ras4B in a Raf-isoform-dependent manner. Overall, these results provide new insights into the spatial organization of the membrane-associated Raf-Ras signaling module for the various Raf isoforms, which is important for understanding the activation of Raf kinases and required for the development of drugs against cancers through targeting Raf-Ras interactions.
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Affiliation(s)
- Lei Li
- Faculty of Chemistry and Chemical Biology, Physical Chemistry I-Biophysical Chemistry, TU Dortmund University, Otto-Hahn-Str. 4a, D-44227 Dortmund, Germany
| | - Simone Möbitz
- Faculty of Chemistry and Chemical Biology, Physical Chemistry I-Biophysical Chemistry, TU Dortmund University, Otto-Hahn-Str. 4a, D-44227 Dortmund, Germany
| | - Roland Winter
- Faculty of Chemistry and Chemical Biology, Physical Chemistry I-Biophysical Chemistry, TU Dortmund University, Otto-Hahn-Str. 4a, D-44227 Dortmund, Germany
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47
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Multivalent assembly of KRAS with the RAS-binding and cysteine-rich domains of CRAF on the membrane. Proc Natl Acad Sci U S A 2020; 117:12101-12108. [PMID: 32414921 DOI: 10.1073/pnas.1914076117] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Membrane anchoring of farnesylated KRAS is critical for activation of RAF kinases, yet our understanding of how these proteins interact on the membrane is limited to isolated domains. The RAS-binding domain (RBD) and cysteine-rich domain (CRD) of RAF engage KRAS and the plasma membrane, unleashing the kinase domain from autoinhibition. Due to experimental challenges, structural insight into this tripartite KRAS:RBD-CRD:membrane complex has relied on molecular dynamics simulations. Here, we report NMR studies of the KRAS:CRAF RBD-CRD complex. We found that the nucleotide-dependent KRAS-RBD interaction results in transient electrostatic interactions between KRAS and CRD, and we mapped the membrane interfaces of the CRD, RBD-CRD, and the KRAS:RBD-CRD complex. RBD-CRD exhibits dynamic interactions with the membrane through the canonical CRD lipid-binding site (CRD β7-8), as well as an alternative interface comprising β6 and the C terminus of CRD and β2 of RBD. Upon complex formation with KRAS, two distinct states were observed by NMR: State A was stabilized by membrane association of CRD β7-8 and KRAS α4-α5 while state B involved the C terminus of CRD, β3-5 of RBD, and part of KRAS α5. Notably, α4-α5, which has been proposed to mediate KRAS dimerization, is accessible only in state B. A cancer-associated mutation on the state B membrane interface of CRAF RBD (E125K) stabilized state B and enhanced kinase activity and cellular MAPK signaling. These studies revealed a dynamic picture of the assembly of the KRAS-CRAF complex via multivalent and dynamic interactions between KRAS, CRAF RBD-CRD, and the membrane.
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48
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Jang H, Zhang M, Nussinov R. The quaternary assembly of KRas4B with Raf-1 at the membrane. Comput Struct Biotechnol J 2020; 18:737-748. [PMID: 32257057 PMCID: PMC7125320 DOI: 10.1016/j.csbj.2020.03.018] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 03/17/2020] [Accepted: 03/19/2020] [Indexed: 02/07/2023] Open
Abstract
Proximally located in the membrane, oncogenic Ras dimers (or nanoclusters) can recruit and promote Raf dimerization and MAPK (Raf/MEK/ERK) signaling. Among Ras isoforms, KRas4B is the most frequently mutated. Recent data on the binary KRas4B–Raf-1 complex suggested that Raf-1 CRD not only executes membrane anchorage, but also supports the high-affinity interaction of Raf-1 RBD with KRas4B catalytic domain. For a detailed mechanistic picture of Raf activation at the membrane, we employ explicit MD simulations of the quaternary KRas4B–Raf-1 complex. The complex contains two active GTP-bound KRas4B proteins forming a dimer through the allosteric lobe interface and two tandem RBD-CRD segments of Raf-1 interacting with the effector lobes at both ends of the KRas4B dimer. We show that Raf-1 RBD-CRD supports stable KRas4B dimer at preferred interface and orientation at the membrane, thereby cooperatively enhancing the affinity of the KRas4B–Raf-1 interaction. We propose that a Ras dimer at the membrane can increase the population of proximal Raf kinase domains, promoting kinase domain dimerization in the cytoplasm. Collectively, the dynamic Ras–Raf assembly promotes Raf activation not by allostery; instead, Ras activates Raf by shifting its ensemble toward kinase domain-accessible states through enhanced affinity at the membrane.
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Affiliation(s)
- Hyunbum Jang
- Computational Structural Biology Section, Basic Science Program, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Mingzhen Zhang
- Computational Structural Biology Section, Basic Science Program, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Ruth Nussinov
- Computational Structural Biology Section, Basic Science Program, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA.,Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
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49
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Sarkar S, García AE. Presence or Absence of Ras Dimerization Shows Distinct Kinetic Signature in Ras-Raf Interaction. Biophys J 2020; 118:1799-1810. [PMID: 32199071 DOI: 10.1016/j.bpj.2020.03.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 12/30/2019] [Accepted: 03/02/2020] [Indexed: 02/07/2023] Open
Abstract
Initiations of cell signaling pathways often occur through the formation of multiprotein complexes that form through protein-protein interactions. Therefore, detecting their presence is central to understanding the function of a cell signaling pathway, aberration of which often leads to fatal diseases, including cancers. However, the multiprotein complexes are often difficult to detect using microscopes due to their small sizes. Therefore, currently, their presence can be only detected through indirect means. In this article, we propose to investigate the presence or absence of protein complexes through some easily measurable kinetic parameters, such as activation rates. As a proof of concept, we investigate the Ras-Raf system, a well-characterized cell signaling system. It has been hypothesized that Ras dimerization is necessary to create activated Raf dimers. Although there are circumstantial evidences supporting the Ras dimerization hypothesis, direct proof of Ras dimerization is still inconclusive. In the absence of conclusive direct experimental proof, this hypothesis can only be examined through indirect evidences of Ras dimerization. In this article, using a multiscale simulation technique, we provide multiple criteria that distinguishes an activation mechanism involving Ras dimerization from another mechanism that does not involve Ras dimerization. The provided criteria will be useful in the investigation of not only Ras-Raf interaction but also other two-protein interactions.
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Affiliation(s)
- Sumantra Sarkar
- Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico
| | - Angel E García
- Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico.
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50
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Neale C, García AE. The Plasma Membrane as a Competitive Inhibitor and Positive Allosteric Modulator of KRas4B Signaling. Biophys J 2020; 118:1129-1141. [PMID: 32027820 PMCID: PMC7063485 DOI: 10.1016/j.bpj.2019.12.039] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 12/04/2019] [Accepted: 12/18/2019] [Indexed: 12/31/2022] Open
Abstract
Mutant Ras proteins are important drivers of human cancers, yet no approved drugs act directly on this difficult target. Over the last decade, the idea has emerged that oncogenic signaling can be diminished by molecules that drive Ras into orientations in which effector-binding interfaces are occluded by the cell membrane. To support this approach to drug discovery, we characterize the orientational preferences of membrane-bound K-Ras4B in 1.45-ms aggregate time of atomistic molecular dynamics simulations. Individual simulations probe active or inactive states of Ras on membranes with or without anionic lipids. We find that the membrane orientation of Ras is relatively insensitive to its bound guanine nucleotide and activation state but depends strongly on interactions with anionic phosphatidylserine lipids. These lipids slow Ras' translational and orientational diffusion and promote a discrete population in which small changes in orientation control Ras' competence to bind multiple regulator and effector proteins. Our results suggest that compound-directed conversion of constitutively active mutant Ras into functionally inactive forms may be accessible via subtle perturbations of Ras' orientational preferences at the membrane surface.
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Affiliation(s)
- Chris Neale
- Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, New Mexico
| | - Angel E García
- Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico.
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