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Aupič J, Pokorná P, Ruthstein S, Magistrato A. Predicting Conformational Ensembles of Intrinsically Disordered Proteins: From Molecular Dynamics to Machine Learning. J Phys Chem Lett 2024:8177-8186. [PMID: 39093570 DOI: 10.1021/acs.jpclett.4c01544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/04/2024]
Abstract
Intrinsically disordered proteins and regions (IDP/IDRs) are ubiquitous across all domains of life. Characterized by a lack of a stable tertiary structure, IDP/IDRs populate a diverse set of transiently formed structural states that can promiscuously adapt upon binding with specific interaction partners and/or certain alterations in environmental conditions. This malleability is foundational for their role as tunable interaction hubs in core cellular processes such as signaling, transcription, and translation. Tracing the conformational ensemble of an IDP/IDR and its perturbation in response to regulatory cues is thus paramount for illuminating its function. However, the conformational heterogeneity of IDP/IDRs poses several challenges. Here, we review experimental and computational methods devised to disentangle the conformational landscape of IDP/IDRs, highlighting recent computational advances that permit proteome-wide scans of IDP/IDRs conformations. We briefly evaluate selected computational methods using the disordered N-terminal of the human copper transporter 1 as a test case and outline further challenges in IDP/IDRs ensemble prediction.
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Affiliation(s)
- Jana Aupič
- CNR-IOM at International School for Advanced Studies (SISSA/ISAS), via Bonomea 265, 34136 Trieste, Italy
| | - Pavlína Pokorná
- CNR-IOM at International School for Advanced Studies (SISSA/ISAS), via Bonomea 265, 34136 Trieste, Italy
| | - Sharon Ruthstein
- Department of Chemistry, Faculty of Exact Sciences and the Institute for Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, 5290002 Ramat-Gan, Israel
| | - Alessandra Magistrato
- CNR-IOM at International School for Advanced Studies (SISSA/ISAS), via Bonomea 265, 34136 Trieste, Italy
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2
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Ajmal A, Danial M, Zulfat M, Numan M, Zakir S, Hayat C, Alabbosh KF, Zaki MEA, Ali A, Wei D. In Silico Prediction of New Inhibitors for Kirsten Rat Sarcoma G12D Cancer Drug Target Using Machine Learning-Based Virtual Screening, Molecular Docking, and Molecular Dynamic Simulation Approaches. Pharmaceuticals (Basel) 2024; 17:551. [PMID: 38794122 PMCID: PMC11124053 DOI: 10.3390/ph17050551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 03/24/2024] [Accepted: 03/27/2024] [Indexed: 05/26/2024] Open
Abstract
Single-point mutations in the Kirsten rat sarcoma (KRAS) viral proto-oncogene are the most common cause of human cancer. In humans, oncogenic KRAS mutations are responsible for about 30% of lung, pancreatic, and colon cancers. One of the predominant mutant KRAS G12D variants is responsible for pancreatic cancer and is an attractive drug target. At the time of writing, no Food and Drug Administration (FDA) approved drugs are available for the KRAS G12D mutant. So, there is a need to develop an effective drug for KRAS G12D. The process of finding new drugs is expensive and time-consuming. On the other hand, in silico drug designing methodologies are cost-effective and less time-consuming. Herein, we employed machine learning algorithms such as K-nearest neighbor (KNN), support vector machine (SVM), and random forest (RF) for the identification of new inhibitors against the KRAS G12D mutant. A total of 82 hits were predicted as active against the KRAS G12D mutant. The active hits were docked into the active site of the KRAS G12D mutant. Furthermore, to evaluate the stability of the compounds with a good docking score, the top two complexes and the standard complex (MRTX-1133) were subjected to 200 ns MD simulation. The top two hits revealed high stability as compared to the standard compound. The binding energy of the top two hits was good as compared to the standard compound. Our identified hits have the potential to inhibit the KRAS G12D mutation and can help combat cancer. To the best of our knowledge, this is the first study in which machine-learning-based virtual screening, molecular docking, and molecular dynamics simulation were carried out for the identification of new promising inhibitors for the KRAS G12D mutant.
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Affiliation(s)
- Amar Ajmal
- Department of Biochemistry, Abdul Wali Khan University Mardan, Mardan 23200, Pakistan
| | - Muhammad Danial
- Department of Biochemistry, Abdul Wali Khan University Mardan, Mardan 23200, Pakistan
| | - Maryam Zulfat
- Department of Biochemistry, Abdul Wali Khan University Mardan, Mardan 23200, Pakistan
| | - Muhammad Numan
- Department of Biochemistry, Abdul Wali Khan University Mardan, Mardan 23200, Pakistan
| | - Sidra Zakir
- Department of Chemistry, Abdul Wali Khan University Mardan, Mardan 23200, Pakistan
| | - Chandni Hayat
- Department of Biochemistry, Abdul Wali Khan University Mardan, Mardan 23200, Pakistan
| | | | - Magdi E. A. Zaki
- Department of Chemistry, College of Science, Imam Mohammad Ibn Saud Islamic University, Riyadh 11623, Saudi Arabia
| | - Arif Ali
- Department of Bioinformatics and Biological Statistics, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Dongqing Wei
- State Key Laboratory of Microbial Metabolism, Shanghai-Islamabad-Belgrade Joint Innovation Center on Antibacterial Resistances, Joint International Research Laboratory of Metabolic & Developmental Sciences and School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200030, China
- Zhongjing Research and Industrialization Institute of Chinese Medicine, Zhongguancun Scientific Park, Meixi, Nanyang 473006, China
- Henan Biological Industry Group, 41 Nongye East Rd., Jinshui, Zhengzhou 450008, China
- Peng Cheng National Laboratory, Vanke Cloud City Phase I Building 8, Xili Street, Nashan District, Shenzhen 518055, China
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3
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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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Hu F, Wang Y, Zeng J, Deng X, Xia F, Xu X. Unveiling the State Transition Mechanisms of Ras Proteins through Enhanced Sampling and QM/MM Simulations. J Phys Chem B 2024; 128:1418-1427. [PMID: 38323538 DOI: 10.1021/acs.jpcb.3c07666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2024]
Abstract
In cells, wild-type RasGTP complexes exist in two distinct states: active State 2 and inactive State 1. These complexes regulate their functions by transitioning between the two states. However, the mechanisms underlying this state transition have not been clearly elucidated. To address this, we conducted a detailed simulation study to characterize the energetics of the stable states involved in the state transitions of the HRasGTP complex, specifically from State 2 to State 1. This was achieved by employing multiscale quantum mechanics/molecular mechanics and enhanced sampling molecular dynamics methods. Based on the simulation results, we constructed the two-dimensional free energy landscapes that provide crucial information about the conformational changes of the HRasGTP complex from State 2 to State 1. Furthermore, we also explored the conformational changes from the intermediate state to the product state during guanosine triphosphate hydrolysis. This study on the conformational changes involved in the HRas state transitions serves as a valuable reference for understanding the corresponding events of both KRas and NRas as well.
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Affiliation(s)
- Fangchen Hu
- School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China
| | - Yiqiu Wang
- School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China
| | - Juan Zeng
- School of Biomedical Engineering, Guangdong Medical University, Dongguan 523808, China
| | - Xianming Deng
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Fei Xia
- School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China
| | - Xin Xu
- Collaborative Innovation Center of Chemistry for Energy Materials, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, MOE Key Laboratory of Computational Physical Sciences, Department of Chemistry, Fudan University, Shanghai 200433, China
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5
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Haspel N, Jang H, Nussinov R. Allosteric Activation of RhoA Complexed with p115-RhoGEF Deciphered by Conformational Dynamics. J Chem Inf Model 2024; 64:862-873. [PMID: 38215280 DOI: 10.1021/acs.jcim.3c01412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2024]
Abstract
The Ras homologue family member A (RhoA) is a member of the Rho family, a subgroup of the Ras superfamily. RhoA interacts with the 115 kDa guanine nucleotide exchange factor (p115-RhoGEF), which assists in activation and binding with downstream effectors. Here, we use molecular dynamics (MD) simulations and essential dynamics analysis of the inactive RhoA-GDP and active RhoA-GTP, when bound to p115-RhoGEF to decipher the mechanism of RhoA activation at the structural level. We observe that inactive RhoA-GDP maintains its position near the catalytic site on the Dbl homology (DH) domain of p115-RhoGEF through the interaction of its Switch I region with the DH domain. We further show that the active RhoA-GTP is engaged in more interactions with the p115-RhoGEF membrane-bound Pleckstrin homology (PH) domain as compared to RhoA-GDP. We hypothesize that the role of the interactions between the active RhoA-GTP and the PH domain is to help release it from the DH domain upon activation. Our results support this premise, and our simulations uncover the beginning of this process and provide structural details. They also point to allosteric communication pathways that take part in RhoA activation to promote and strengthen the interaction between the active RhoA-GTP and the PH domain. Allosteric regulation also occurs among other members of the Rho superfamily. Collectively, we suggest that in the activation process, the role of the RhoA-GTP interaction with the PH domain is to release RhoA-GTP from the DH domain after activation, making it available to downstream effectors.
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Affiliation(s)
- Nurit Haspel
- Department of Computer Science, University of Massachusetts Boston, Boston, Massachusetts 02125, United States
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Cancer Innovation Laboratory, National Cancer Institute, Frederick, Maryland 21702, United States
| | - Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Cancer Innovation Laboratory, National Cancer Institute, Frederick, Maryland 21702, United States
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
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Das AS, Sherry EC, Vaughan RM, Henderson ML, Zieba J, Uhl KL, Koehn O, Bupp CP, Rajasekaran S, Li X, Chhetri SB, Nissim S, Williams CL, Prokop JW. The complex, dynamic SpliceOme of the small GTPase transcripts altered by technique, sex, genetics, tissue specificity, and RNA base editing. Front Cell Dev Biol 2022; 10:1033695. [PMID: 36467401 PMCID: PMC9714508 DOI: 10.3389/fcell.2022.1033695] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 11/01/2022] [Indexed: 04/04/2024] Open
Abstract
The small GTPase family is well-studied in cancer and cellular physiology. With 162 annotated human genes, the family has a broad expression throughout cells of the body. Members of the family have multiple exons that require splicing. Yet, the role of splicing within the family has been underexplored. We have studied the splicing dynamics of small GTPases throughout 41,671 samples by integrating Nanopore and Illumina sequencing techniques. Within this work, we have made several discoveries. 1). Using the GTEx long read data of 92 samples, each small GTPase gene averages two transcripts, with 83 genes (51%) expressing two or more isoforms. 2). Cross-tissue analysis of GTEx from 17,382 samples shows 41 genes (25%) expressing two or more protein-coding isoforms. These include protein-changing transcripts in genes such as RHOA, RAB37, RAB40C, RAB4B, RAB5C, RHOC, RAB1A, RAN, RHEB, RAC1, and KRAS. 3). The isolation and library technique of the RNAseq influences the abundance of non-sense-mediated decay and retained intron transcripts of small GTPases, which are observed more often in genes than appreciated. 4). Analysis of 16,243 samples of "Blood PAXgene" identified seven genes (3.7%; RHOA, RAB40C, RAB4B, RAB37, RAB5B, RAB5C, RHOC) with two or more transcripts expressed as the major isoform (75% of the total gene), suggesting a role of genetics in altering splicing. 5). Rare (ARL6, RAB23, ARL13B, HRAS, NRAS) and common variants (GEM, RHOC, MRAS, RAB5B, RERG, ARL16) can influence splicing and have an impact on phenotypes and diseases. 6). Multiple genes (RAB9A, RAP2C, ARL4A, RAB3A, RAB26, RAB3C, RASL10A, RAB40B, and HRAS) have sex differences in transcript expression. 7). Several exons are included or excluded for small GTPase genes (RASEF, KRAS, RAC1, RHEB, ARL4A, RHOA, RAB30, RHOBTB1, ARL16, RAP1A) in one or more forms of cancer. 8). Ten transcripts are altered in hypoxia (SAR1B, IFT27, ARL14, RAB11A, RAB10, RAB38, RAN, RIT1, RAB9A) with RHOA identified to have a transient 3'UTR RNA base editing at a conserved site found in all of its transcripts. Overall, we show a remarkable and dynamic role of splicing within the small GTPase family that requires future explorations.
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Affiliation(s)
- Akansha S. Das
- Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, MI, United States
- Department of Biology, Washington and Jefferson College, Washington, PA, United States
| | - Emily C. Sherry
- Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, MI, United States
- Department of Cell and Molecular Biology, Grand Valley State University, Allendale, MI, United States
| | - Robert M. Vaughan
- Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, MI, United States
| | - Marian L. Henderson
- Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, MI, United States
- The Department of Biology, Calvin University, Grand Rapids, MI, United States
| | - Jacob Zieba
- Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, MI, United States
- Genetics and Genome Sciences Program, BioMolecular Science, Michigan State University, East Lansing, MI, United States
| | - Katie L. Uhl
- Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, MI, United States
| | - Olivia Koehn
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Caleb P. Bupp
- Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, MI, United States
- Medical Genetics, Spectrum Health and Helen DeVos Children’s Hospital, Grand Rapids, MI, United States
| | - Surender Rajasekaran
- Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, MI, United States
- Department of Pediatric Critical Care Medicine, Helen DeVos Children’s Hospital Spectrum Health, Grand Rapids, MI, United States
- Office of Research, Spectrum Health, Grand Rapids, MI, United States
| | - Xiaopeng Li
- Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, MI, United States
| | - Surya B. Chhetri
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MA, United States
| | - Sahar Nissim
- Genetics and Gastroenterology Divisions, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, United States
- Dana-Farber Cancer Institute, Boston, MA, United States
- Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA, United States
| | - Carol L. Williams
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Jeremy W. Prokop
- Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, MI, United States
- Genetics and Genome Sciences Program, BioMolecular Science, Michigan State University, East Lansing, MI, United States
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, United States
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Zhang H, Ni D, Fan J, Li M, Zhang J, Hua C, Nussinov R, Lu S. Markov State Models and Molecular Dynamics Simulations Reveal the Conformational Transition of the Intrinsically Disordered Hypervariable Region of K-Ras4B to the Ordered Conformation. J Chem Inf Model 2022; 62:4222-4231. [PMID: 35994329 DOI: 10.1021/acs.jcim.2c00591] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
K-Ras4B, the most frequently mutated Ras isoform in human tumors, plays a vital part in cell growth, differentiation, and survival. Its tail, the C-terminal hypervariable region (HVR), is involved in anchoring K-Ras4B at the cellular plasma membrane and in isoform-specific protein-protein interactions and signaling. In the inactive guanosine diphosphate-bound state, the intrinsically disordered HVR interacts with the catalytic domain at the effector-binding region, rendering K-Ras4B in its autoinhibited state. Activation releases the HVR from the catalytic domain, with its ensemble favoring an ordered α-helical structure. The large-scale conformational transition of the HVR from the intrinsically disordered to the ordered conformation remains poorly understood. Here, we deploy a computational scheme that integrates a transition path-generation algorithm, extensive molecular dynamics simulation, and Markov state model analysis to investigate the conformational landscape of the HVR transition pathway. Our findings reveal a stepwise pathway for the HVR transition and uncover several key conformational substates along the transition pathway. Importantly, key interactions between the HVR and the catalytic domain are unraveled, highlighting the pathogenesis of K-Ras4B mild mutations in several congenital developmental anomaly syndromes. Together, these findings provide a deeper understanding of the HVR transition mechanism and the regulation of K-Ras4B activity at an atomic level.
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Affiliation(s)
- Hao Zhang
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200011, China
| | - Duan Ni
- The Charles Perkins Centre, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Jigang Fan
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, School of Medicine, Shanghai Jiao Tong University, Shanghai 200025, China
| | - Minyu Li
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, School of Medicine, Shanghai Jiao Tong University, Shanghai 200025, China
| | - Jian Zhang
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, School of Medicine, Shanghai Jiao Tong University, Shanghai 200025, China
| | - Chen Hua
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200011, China
| | - Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research, Cancer Innovation Laboratory, National Cancer Institute, Frederick, Maryland 21702, United States.,Department of Human Genetics and Molecular Medicine, Sackler School of Medicine, Sackler Institute of Molecular Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Shaoyong Lu
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, School of Medicine, Shanghai Jiao Tong University, Shanghai 200025, China.,Medicinal Chemistry and Bioinformatics Centre, School of Medicine, Shanghai Jiao Tong University, Shanghai 200025, China
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8
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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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9
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Zeng J, Chen J, Xia F, Cui Q, Deng X, Xu X. Identification of functional substates of KRas during GTP hydrolysis with enhanced sampling simulations. Phys Chem Chem Phys 2022; 24:7653-7665. [PMID: 35297922 PMCID: PMC8972078 DOI: 10.1039/d2cp00274d] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
As the hub of major signaling pathways, Ras proteins are implicated in 19% of tumor-caused cancers due to perturbations in their conformational and/or catalytic properties. Despite numerous studies, the functions of the conformational substates for the most important isoform, KRas, remain elusive. In this work, we perform an extensive simulation analysis on the conformational landscape of KRas in its various chemical states during the GTP hydrolysis cycle: the reactant state KRasGTP·Mg2+, the intermediate state KRasGDP·Pi·Mg2+ and the product state KRasGDP·Mg2+. The results from enhanced sampling simulations reveal that State 1 of KRasGTP·Mg2+ has multiple stable substates in solution, one of which might account for interacting with GEFs. State 2 of KRasGTP·Mg2+ features two substates "Tyr32in" and "Tyr32out", which are poised to interact with effectors and GAPs, respectively. For the intermediate state KRasGDP·Pi·Mg2+, Gln61 and Pi are found to assume a broad set of conformations, which might account for the weak oncogenic effect of Gln61 mutations in KRas in contrast to the situation in HRas and NRas. Finally, the product state KRasGDP·Mg2+ has more than two stable substates in solution, pointing to a conformation-selection mechanism for complexation with GEFs. Based on these results, some specific inhibition strategies for targeting the binding sites of the high-energy substates of KRas during GTP hydrolysis are discussed.
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Affiliation(s)
- Juan Zeng
- School of Biomedical Engineering, Guangdong Medical University, Dongguan 523808, China
| | - Jian Chen
- School of Chemistry and Molecular Engineering, NYU-ECNU Center for Computational Chemistry at NYU Shanghai, East China Normal University, Shanghai 200062, China.
| | - Fei Xia
- School of Chemistry and Molecular Engineering, NYU-ECNU Center for Computational Chemistry at NYU Shanghai, East China Normal University, Shanghai 200062, China.
| | - Qiang Cui
- Departments of Chemistry, Physics and Biomedical Engineering, Boston University, 590 Commonwealth Avenue, Boston, MA 02215, USA
| | - Xianming Deng
- State Key Laboratory of Cellular Stress Biology Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Fujian 361101, China.
| | - Xin Xu
- Collaborative Innovation Center of Chemistry for Energy Materials, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, MOE Key Laboratory of Computational Physical Sciences, Department of Chemistry, Fudan University, Shanghai 200433, China.
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10
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Xiong Y, Zeng J, Xia F, Cui Q, Deng X, Xu X. Conformations and binding pockets of HRas and its guanine nucleotide exchange factors complexes in the guanosine triphosphate exchange process. J Comput Chem 2022; 43:906-916. [PMID: 35324017 PMCID: PMC9191747 DOI: 10.1002/jcc.26846] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Revised: 03/03/2022] [Accepted: 03/04/2022] [Indexed: 12/23/2022]
Abstract
The human Son of Sevenless (SOS) activates the signal-transduction protein Ras by forming the complex SOS·Ras and accelerating the guanosine triphosphate (GTP) exchange in Ras. Inhibition of SOS·Ras could regulate the function of Ras in cells and has emerged as an effective strategy for battling Ras related cancers. A key factor to the success of this approach is to understand the conformational change of Ras during the GTP exchange process. In this study, we perform an extensive molecular dynamics simulation to characterize the specific conformations of Ras without and with guanine nucleotide exchange factors (GEFs) of SOS, especially for the substates of State 1 of HRasGTP∙Mg2+ . The potent binding pockets on the surfaces of the RasGDP∙Mg2+ , the S1.1 and S1.2 substates in State 1 of RasGTP∙Mg2+ and the ternary complexes with SOS are predicted, including the binding sites of other domains of SOS. These findings help to obtain a more thorough understanding of Ras functions in the GTP cycling process and provide a structural foundation for future drug design.
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Affiliation(s)
- Yuqing Xiong
- School of Chemistry and Molecular Engineering, NYU-ECNU Center for Computational Chemistry at NYU Shanghai, East China Normal University, Shanghai, China
| | - Juan Zeng
- School of Biomedical Engineering, Guangdong Medical University, Dongguan, China
| | - Fei Xia
- School of Chemistry and Molecular Engineering, NYU-ECNU Center for Computational Chemistry at NYU Shanghai, East China Normal University, Shanghai, China
| | - Qiang Cui
- Departments of Chemistry, Physics and Biomedical Engineering, Boston University, Boston, Massachusetts, USA
| | - Xianming Deng
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Xiamen, China
| | - Xin Xu
- Collaborative Innovation Center of Chemistry for Energy Materials, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, MOE Key Laboratory of Computational Physical Sciences, Departments of Chemistry, Fudan University, Shanghai, China
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11
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Aran V. K-RAS4A: Lead or Supporting Role in Cancer Biology? Front Mol Biosci 2021; 8:729830. [PMID: 34604308 PMCID: PMC8479197 DOI: 10.3389/fmolb.2021.729830] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 09/01/2021] [Indexed: 11/19/2022] Open
Abstract
The RAS oncogene is one of the most frequently mutated genes in human cancer, with K-RAS having a leading role in tumorigenesis. K-RAS undergoes alternative splicing, and as a result its transcript generates two gene products K-RAS4A and K-RAS4B, which are affected by the same oncogenic mutations, are highly homologous, and are expressed in a variety of human tissues at different levels. In addition, both isoforms localise to the plasma membrane by distinct targeting motifs. While some evidence suggests nonredundant functions for both splice variants, most work to date has focused on K-RAS4B, or even just K-RAS (i.e., without differentiating between the splice variants). This review aims to address the most relevant evidence published regarding K-RAS4A and to discuss if this “minor” isoform could also play a leading role in cancer, concluding that a significant body of evidence supports a leading role rather than a supporting (or secondary) role for K-RAS4A in cancer biology.
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Affiliation(s)
- Veronica Aran
- Laboratorio de Biomedicina Do Cérebro, Instituto Estadual Do Cérebro Paulo Niemeyer, Rio de Janeiro, Brazil
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12
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Ramos-Kuri M, Meka SH, Salamanca-Buentello F, Hajjar RJ, Lipskaia L, Chemaly ER. Molecules linked to Ras signaling as therapeutic targets in cardiac pathologies. Biol Res 2021; 54:23. [PMID: 34344467 PMCID: PMC8330049 DOI: 10.1186/s40659-021-00342-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 06/26/2021] [Indexed: 12/11/2022] Open
Abstract
Abstract The Ras family of small Guanosine Triphosphate (GTP)-binding proteins (G proteins) represents one of the main components of intracellular signal transduction required for normal cardiac growth, but is also critically involved in the development of cardiac hypertrophy and heart failure. The present review provides an update on the role of the H-, K- and N-Ras genes and their related pathways in cardiac diseases. We focus on cardiac hypertrophy and heart failure, where Ras has been studied the most. We also review other cardiac diseases, like genetic disorders related to Ras. The scope of the review extends from fundamental concepts to therapeutic applications. Although the three Ras genes have a nearly identical primary structure, there are important functional differences between them: H-Ras mainly regulates cardiomyocyte size, whereas K-Ras regulates cardiomyocyte proliferation. N-Ras is the least studied in cardiac cells and is less associated to cardiac defects. Clinically, oncogenic H-Ras causes Costello syndrome and facio-cutaneous-skeletal syndromes with hypertrophic cardiomyopathy and arrhythmias. On the other hand, oncogenic K-Ras and alterations of other genes of the Ras-Mitogen-Activated Protein Kinase (MAPK) pathway, like Raf, cause Noonan syndrome and cardio-facio-cutaneous syndromes characterized by cardiac hypertrophy and septal defects. We further review the modulation by Ras of key signaling pathways in the cardiomyocyte, including: (i) the classical Ras-Raf-MAPK pathway, which leads to a more physiological form of cardiac hypertrophy; as well as other pathways associated with pathological cardiac hypertrophy, like (ii) The SAPK (stress activated protein kinase) pathways p38 and JNK; and (iii) The alternative pathway Raf-Calcineurin-Nuclear Factor of Activated T cells (NFAT). Genetic alterations of Ras isoforms or of genes in the Ras-MAPK pathway result in Ras-opathies, conditions frequently associated with cardiac hypertrophy or septal defects among other cardiac diseases. Several studies underline the potential role of H- and K-Ras as a hinge between physiological and pathological cardiac hypertrophy, and as potential therapeutic targets in cardiac hypertrophy and failure. Graphic abstract ![]()
The Ras (Rat Sarcoma) gene family is a group of small G proteins Ras is regulated by growth factors and neurohormones affecting cardiomyocyte growth and hypertrophy Ras directly affects cardiomyocyte physiological and pathological hypertrophy Genetic alterations of Ras and its pathways result in various cardiac phenotypes Ras and its pathway are differentially regulated in acquired heart disease Ras modulation is a promising therapeutic target in various cardiac conditions.
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Affiliation(s)
- Manuel Ramos-Kuri
- Instituto Nacional de Cancerología, Unidad de Investigación Biomédica en Cáncer, Secretarìa de Salud/Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, México.,Researcher of the Facultad de Bioética, Cátedra de Infertilidad, Universidad Anáhuac, Mexico City, México.,Centro de Investigación en Bioética y Genética, Querétaro, México
| | - Sri Harika Meka
- Division of Nephrology, Department of Medicine, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Clinical and Translational Research Center, 875 Ellicott Street, Suite 8030B, Buffalo, NY, 14203, USA
| | - Fabio Salamanca-Buentello
- University of Toronto Institute of Medical Science, Medical Sciences Building, 1 King's College Circle, Room 2374, Toronto, ON, M5S 1A8, Canada
| | | | - Larissa Lipskaia
- INSERM U955 and Département de Physiologie, Hôpital Henri Mondor, FHU SENEC, AP-HP, and Université Paris-Est Créteil (UPEC), 94010, Créteil, France
| | - Elie R Chemaly
- Division of Nephrology, Department of Medicine, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Clinical and Translational Research Center, 875 Ellicott Street, Suite 8030B, Buffalo, NY, 14203, USA.
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13
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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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14
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Zeng J, Weng J, Zhang Y, Xia F, Cui Q, Xu X. Conformational Features of Ras: Key Hydrogen-Bonding Interactions of Gln61 in the Intermediate State during GTP Hydrolysis. J Phys Chem B 2021; 125:8805-8813. [PMID: 34324329 DOI: 10.1021/acs.jpcb.1c04679] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The Ras protein is one of the most important drug targets for battling cancers. To effectively design novel drugs of Ras, we characterize here its conformational ensembles for the hydrolysis intermediate state RasGDP·Pi and the product state RasGDP by extensive replica-exchange molecular dynamics simulations. Several substates for RasGDP·Pi have been identified, while structural analyses have revealed an unrecognized hydrogen-bonding network that stabilizes the hydrolysis intermediate state. More interestingly, Gln61, which is involved in numerous oncogenic mutations, was found to be engaged in this hydrogen-bonding network, adopting a specific conformation that always points to Pi in contrast to that in the RasGTP state. The simulations also reveal that RasGDP has more than one substate, suggesting a conformational selection mechanism for the interaction between Ras and the guanine nucleotide exchange factors (GEFs). These findings offer new opportunities for the drug design of Ras by stabilizing the hydrolysis intermediate or disrupting its interaction with the GEFs.
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Affiliation(s)
- Juan Zeng
- School of Biomedical Engineering, Guangdong Medical University, Dongguan 523808, China
| | - Jingwei Weng
- Collaborative Innovation Center of Chemistry for Energy Materials, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, MOE Key Laboratory of Computational Physical Sciences, Departments of Chemistry, Fudan University, Shanghai 200433, China
| | - Yuwei Zhang
- School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China
| | - Fei Xia
- School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China.,Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, NYU-ECNU Center for Computational Chemistry at NYU Shanghai, Shanghai 200062, China
| | - Qiang Cui
- Departments of Chemistry, Physics and Biomedical Engineering, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States
| | - Xin Xu
- Collaborative Innovation Center of Chemistry for Energy Materials, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, MOE Key Laboratory of Computational Physical Sciences, Departments of Chemistry, Fudan University, Shanghai 200433, China
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15
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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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16
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Weako J, Jang H, Keskin O, Nussinov R, Gursoy A. The structural basis of Akt PH domain interaction with calmodulin. Biophys J 2021; 120:1994-2008. [PMID: 33775637 PMCID: PMC8204387 DOI: 10.1016/j.bpj.2021.03.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 03/10/2021] [Accepted: 03/18/2021] [Indexed: 11/17/2022] Open
Abstract
Akt plays a key role in the Ras/PI3K/Akt/mTOR signaling pathway. In breast cancer, Akt translocation to the plasma membrane is enabled by the interaction of its pleckstrin homology domain (PHD) with calmodulin (CaM). At the membrane, the conformational change promoted by PIP3 releases CaM and facilitates Thr308 and Ser473 phosphorylation and activation. Here, using modeling and molecular dynamics simulations, we aim to figure out how CaM interacts with Akt's PHD at the atomic level. Our simulations show that CaM-PHD interaction is thermodynamically stable and involves a β-strand rather than an α-helix, in agreement with NMR data, and that electrostatic and hydrophobic interactions are critical. The PHD interacts with CaM lobes; however, multiple modes are possible. IP4, the polar head of PIP3, weakens the CaM-PHD interaction, implicating the release mechanism at the plasma membrane. Recently, we unraveled the mechanism of PI3Kα activation at the atomistic level and the structural basis for Ras role in the activation. Here, our atomistic structural data clarify the mechanism of how CaM interacts, delivers, and releases Akt-the next node in the Ras/PI3K pathway-at the plasma membrane.
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Affiliation(s)
- Jackson Weako
- Computational Science and Engineering Program, Koç University, Istanbul, Turkey
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, Maryland
| | - Ozlem Keskin
- Department of Chemical and Biological Engineering, Koç University, Istanbul, Turkey
| | - 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.
| | - Attila Gursoy
- Department of Computer Engineering, Koç University, Istanbul, Turkey.
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17
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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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18
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Haspel N, Jang H, Nussinov R. Active and Inactive Cdc42 Differ in Their Insert Region Conformational Dynamics. Biophys J 2021; 120:306-318. [PMID: 33347888 PMCID: PMC7840443 DOI: 10.1016/j.bpj.2020.12.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 12/08/2020] [Accepted: 12/10/2020] [Indexed: 12/26/2022] Open
Abstract
Cell division control protein 42 homolog (Cdc42) protein, a Ras superfamily GTPase, regulates cellular activities, including cancer progression. Using all-atom molecular dynamics (MD) simulations and essential dynamic analysis, we investigated the structure and dynamics of the catalytic domains of GDP-bound (inactive) and GTP-bound (active) Cdc42 in solution. We discovered substantial differences in the dynamics of the inactive and active forms, particularly in the "insert region" (residues 122-135), which plays a role in Cdc42 activation and binding to effectors. The insert region has larger conformational flexibility in the GDP-bound Cdc42 than in the GTP-bound Cdc42. The G2 loop and switch I at the effector lobe of the catalytic domain exhibit large conformational changes in both the GDP- and the GTP-bound systems, but in the GTP-bound Cdc42, the switch I interactions with GTP are retained. Oncogenic mutations were identified in the Ras superfamily. In Cdc42, the G12V and Q61L mutations decrease the GTPase activity. We simulated these mutations in both GDP- and GTP-bound Cdc42. Although the overall structural organization is quite similar between the wild type and the mutants, there are small differences in the conformational dynamics, especially in the two switch regions. Taken together, the G12V and Q61L mutations may play a role similar to their K-Ras counterparts in nucleotide binding and activation. The conformational differences, which are mainly in the insert region and, to a lesser extent, in the switch regions flanking the nucleotide binding site, can shed light on binding and activation. We propose that the differences are due to a network of hydrogen bonds that gets disrupted when Cdc42 is bound to GDP, a disruption that does not exist in other Rho GTPases. The differences in the dynamics between the two Cdc42 states suggest that the inactive conformation has reduced ability to bind to effectors.
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Affiliation(s)
- Nurit Haspel
- Department of Computer Science, University of Massachusetts Boston, Boston, Massachusetts
| | - 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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19
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Menyhárd DK, Pálfy G, Orgován Z, Vida I, Keserű GM, Perczel A. Structural impact of GTP binding on downstream KRAS signaling. Chem Sci 2020; 11:9272-9289. [PMID: 34094198 PMCID: PMC8161693 DOI: 10.1039/d0sc03441j] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Oncogenic RAS proteins, involved in ∼30% of human tumors, are molecular switches of various signal transduction pathways. Here we apply a new protocol for the NMR study of KRAS in its (inactive) GDP- and (activated) GTP-bound form, allowing a comprehensive analysis of the backbone dynamics of its WT-, G12C- and G12D variants. We found that Tyr32 shows opposite mobility with respect to the backbone of its surroundings: it is more flexible in the GDP-bound form while more rigid in GTP-complexes (especially in WT- and G12D-GTP). Using the G12C/Y32F double mutant, we showed that the presence of the hydroxyl group of Tyr32 has a marked effect on the G12C-KRAS-GTP system as well. Molecular dynamics simulations indicate that Tyr32 is linked to the γ-phosphate of GTP in the activated states – an arrangement shown, using QM/MM calculations, to support catalysis. Anchoring Tyr32 to the γ-phosphate contributes to the capture of the catalytic waters participating in the intrinsic hydrolysis of GTP and supports a simultaneous triple proton transfer step (catalytic water → assisting water → Tyr32 → O1G of the γ-phosphate) leading to straightforward product formation. The coupled flip of negatively charged residues of switch I toward the inside of the effector binding pocket potentiates ligand recognition, while positioning of Thr35 to enter the coordination sphere of the Mg2+ widens the pocket. Position 12 mutations do not disturb the capture of Tyr32 by the γ-phosphate, but (partially) displace Gln61, which opens up the catalytic pocket and destabilizes catalytic water molecules thus impairing intrinsic hydrolysis. Nucleotide exchange to the physiological, activated, GTP-bound form of KRAS results in the anchoring of Tyr32 within the active site.![]()
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Affiliation(s)
- Dóra K Menyhárd
- Laboratory of Structural Chemistry and Biology, MTA-ELTE Protein Modelling Research Group, Institute of Chemistry, Eötvös Loránd University Pázmány Péter sétány 1/A 1117 Budapest Hungary
| | - Gyula Pálfy
- Laboratory of Structural Chemistry and Biology, MTA-ELTE Protein Modelling Research Group, Institute of Chemistry, Eötvös Loránd University Pázmány Péter sétány 1/A 1117 Budapest Hungary
| | - Zoltán Orgován
- Medicinal Chemistry Research Group, Research Centre for Natural Sciences Magyar tudósok körútja 2 1117 Budapest Hungary
| | - István Vida
- Laboratory of Structural Chemistry and Biology, MTA-ELTE Protein Modelling Research Group, Institute of Chemistry, Eötvös Loránd University Pázmány Péter sétány 1/A 1117 Budapest Hungary
| | - György M Keserű
- Medicinal Chemistry Research Group, Research Centre for Natural Sciences Magyar tudósok körútja 2 1117 Budapest Hungary
| | - András Perczel
- Laboratory of Structural Chemistry and Biology, MTA-ELTE Protein Modelling Research Group, Institute of Chemistry, Eötvös Loránd University Pázmány Péter sétány 1/A 1117 Budapest Hungary
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20
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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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Pantsar T. The current understanding of KRAS protein structure and dynamics. Comput Struct Biotechnol J 2019; 18:189-198. [PMID: 31988705 PMCID: PMC6965201 DOI: 10.1016/j.csbj.2019.12.004] [Citation(s) in RCA: 132] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 12/06/2019] [Accepted: 12/07/2019] [Indexed: 01/10/2023] Open
Abstract
One of the most common drivers in human cancer is the mutant KRAS protein. Not so long ago KRAS was considered as an undruggable oncoprotein. After a long struggle, however, we finally see some light at the end of the tunnel as promising KRAS targeted therapies are in or approaching clinical trials. In recent years, together with the promising progress in RAS drug discovery, our understanding of KRAS has increased tremendously. This progress has been accompanied with a resurgence of publicly available KRAS structures, which were limited to nine structures less than ten years ago. Furthermore, the ever-increasing computational capacity has made biologically relevant timescales accessible, enabling molecular dynamics (MD) simulations to study the dynamics of KRAS protein in more detail at the atomistic level. In this minireview, my aim is to provide the reader an overview of the publicly available KRAS structural data, insights to conformational dynamics revealed by experiments and what we have learned from MD simulations. Also, I will discuss limitations of the current data and provide suggestions for future research related to KRAS, which would fill out the existing gaps in our knowledge and provide guidance in deciphering this enigmatic oncoprotein.
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Affiliation(s)
- Tatu Pantsar
- Department of Pharmaceutical and Medicinal Chemistry, Institute of Pharmaceutical Sciences, Eberhard Karls University Tübingen, Auf der Morgenstelle 8, 72076 Tübingen, Germany
- School of Pharmacy, University of Eastern Finland, Yliopistonranta 1, 70210 Kuopio, Finland
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22
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Ji M, Ding Y, Li X, Mao N, Chen J. Computational investigation of a ternary model of SnoN-SMAD3-SMAD4 complex. Comput Biol Chem 2019; 83:107159. [PMID: 31743832 DOI: 10.1016/j.compbiolchem.2019.107159] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 10/28/2019] [Accepted: 11/03/2019] [Indexed: 12/18/2022]
Abstract
The transforming growth factor β (TGFβ) plays an essential role in the regulation of cellular processes such as cell proliferation, migration, differentiation, and apoptosis by association with SMAD transcriptional factors that are regulated by the transcriptional regulator SnoN. The crystal structure of SnoN-SMAD4 reveals that SnoN can adopt two binding modes, the open and closed forms, at the interfaces of SMAD4 subunits. Accumulating evidence indicates that SnoN can interact with both SMAD3 and SMAD4 to form a ternary SnoN-SMAD3-SMAD4 complex in the TGFβ signaling pathway. However, how the interaction of SnoN with the SMAD3 and SMAD4 remains unclear. Here, molecular dynamics (MD) simulations and molecular modeling methods were performed to figure out this issue. The simulations reveal that SnoNopen exists in two, open and semi-closed, conformations. Molecular modeling and MD simulation studies suggest that the SnoNclosed form interferes with the SMAD3-SMAD4 protein; in contract, the SnoNopen can form a stable SnoN-SMAD3-SMAD4 complex. These mechanistic mechanisms may help elucidate the detailed engagement of SnoN with two SMAD3 and SMAD4 transcriptional factors in the regulation of TGFβ signaling pathway.
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Affiliation(s)
- Mingfei Ji
- Department of Urology, Changzheng Hospital, Naval Military Medical University, Shanghai, 200003, China
| | - Yelei Ding
- Department of Urology, Changzheng Hospital, Naval Military Medical University, Shanghai, 200003, China
| | - Xiaolong Li
- Department of Orthopedics, Changhai Hospital, Naval Military Medical University, Shanghai, 200433, China.
| | - Ningfang Mao
- Department of Orthopedics, Changhai Hospital, Naval Military Medical University, Shanghai, 200433, China.
| | - Jie Chen
- Department of Urology, Changzheng Hospital, Naval Military Medical University, Shanghai, 200003, China.
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Ni D, Li X, He X, Zhang H, Zhang J, Lu S. Drugging K-Ras G12C through covalent inhibitors: Mission possible? Pharmacol Ther 2019; 202:1-17. [PMID: 31233765 DOI: 10.1016/j.pharmthera.2019.06.007] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Ras, whose mutants are present in approximately 30% of human tumours, is one of the most important oncogenes. Drugging Ras is thus regarded as the quest for the Holy Grail in cancer therapeutics development. Despite more than three decades of efforts, drug discovery targeting Ras constantly fails, rendering Ras undruggable, due to its smooth surface and picomolar affinity towards guanosine substrates. The most frequently mutated isoform of Ras is K-Ras, accounting for >85% of Ras-driven cancers, and one majority of them is the G12C mutation. Recent advances in structural biology shed light on drugging Ras, and one of the cutting-edge breakthroughs is the design of covalent G12C-specific inhibitors targeting the mutated cysteine. This type of inhibitor can be classified into substrate-competitive orthosteric inhibitors and non-competitive allosteric inhibitors. They display improved selectivity and enhanced potency due to their G12-specific and irreversible covalent binding nature. Thus, they represent a new hope for revolutionizing the conventional characterization of Ras as "undruggable" and pave a promising avenue for further drug discovery. Here, we provide comprehensive structural and medicinal chemical insights into K-Ras covalent inhibitors specific for the G12C mutant. We first present an in-depth analysis of the conformations of the inhibitor binding pockets. Then, all the latest covalent ligands selectively inhibiting K-RasG12C are reviewed. Finally, we examine the current challenges faced by this new class of anti-Ras inhibitors.
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Affiliation(s)
- Duan Ni
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Xinyi Li
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Xinheng He
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Hao Zhang
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Jian Zhang
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China; Medicinal Bioinformatics Center, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China.
| | - Shaoyong Lu
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China; Medicinal Bioinformatics Center, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China.
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24
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Zhang M, Li Z, Wang G, Jang H, Sacks DB, Zhang J, Gaponenko V, Nussinov R. Calmodulin (CaM) Activates PI3Kα by Targeting the "Soft" CaM-Binding Motifs in Both the nSH2 and cSH2 Domains of p85α. J Phys Chem B 2018; 122:11137-11146. [PMID: 30047727 PMCID: PMC6422767 DOI: 10.1021/acs.jpcb.8b05982] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PI3Kα is a key lipid kinase in the PI3K/Akt pathway. Its frequent oncogenic mutations make it a primary drug target. Calmodulin (CaM) activates PI3Kα independently of extracellular signals, indicating a significant role in oncogenic PI3Kα activation. Here, we reveal the atomic-scale structures of CaM in complexes with the nSH2 and cSH2 domains of the regulatory p85α subunit of PI3Kα, and illustrate how CaM activates PI3Kα by targeting the "soft 1-5-10" CaM-binding motifs in both nSH2 and cSH2 domains. Experiment observed CaM binding cSH2 first, followed by nSH2 binding hours later. CaM typically prefers binding helical peptides. Here we observe that, unlike in cSH2, the CaM-binding motif in nSH2 populates a mixed β-sheet/α-helix/random coil structure. The population shift from a β-sheet toward CaM's favored α-helical conformation explains why the nSH2 domain needs a longer time for CaM binding in the experiments. The "soft" CaM-binding motifs in both nSH2 and cSH2 domains establish strong CaM-PI3Kα interactions, collectively facilitating PI3Kα activation. This work uncovers the structural basis for CaM-driven PI3Kα activation.
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Affiliation(s)
- Mingzhen Zhang
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research Sponsored by the National Cancer Institute, Frederick, Maryland 21702, United States
| | - Zhigang Li
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Guanqiao Wang
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Ministry of Education, Shanghai Jiao-Tong University School of Medicine, Shanghai 200025, China
| | - Hyunbum Jang
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research Sponsored by the National Cancer Institute, Frederick, Maryland 21702, United States
| | - David B. Sacks
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Jian Zhang
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Ministry of Education, Shanghai Jiao-Tong University School of Medicine, Shanghai 200025, China
| | - Vadim Gaponenko
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Ruth Nussinov
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research Sponsored by the National Cancer Institute, Frederick, Maryland 21702, United States
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
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Liao TJ, Jang H, Fushman D, Nussinov R. Allosteric KRas4B Can Modulate SOS1 Fast and Slow Ras Activation Cycles. Biophys J 2018; 115:629-641. [PMID: 30097175 PMCID: PMC6103739 DOI: 10.1016/j.bpj.2018.07.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 07/18/2018] [Accepted: 07/19/2018] [Indexed: 01/08/2023] Open
Abstract
Membrane-anchored Ras family proteins are activated by guanine nucleotide exchange factors such as SOS1. The CDC25 domain of SOS1 catalyzes GDP-to-GTP exchange, thereby activating Ras. Here, we aim to decipher the activation mechanism of KRas4B, a significantly mutated oncogene. We perform large-scale molecular dynamics simulations on 12 SOS1 systems, scrutinizing each step in two possible KRas4B activation cycles, fast and slow. To activate KRas4B at the CDC25 catalytic site, the allosteric site in the Ras exchanger motif (REM) domain of SOS1 needs to recruit a (nucleotide-bound) KRas4B molecule. Our simulations indicate that KRas4B-GTP interacts with the REM allosteric site more strongly than with the CDC25 catalytic site, consistent with its allosteric role in the GDP-to-GTP exchange. In the fast cycle, the allosteric KRas4B-GTP induces conformational change at the catalytic site. The conformational change facilitates loading KRas4B-GDP at the catalytic site and opening the KRas4B nucleotide-binding site for GDP release and GTP binding. GTP binding reduces the affinity of KRas4B-GTP to the CDC25 catalytic site, resulting in its release. By contrast, in the slow cycle, KRas4B-GDP binds at the allosteric REM site. The limited, altered conformational change that it induces prevents the exact alignments of switch I and II of KRas4B. The increasing binding strength at both binding sites due to interactions of regions other than switch I and II retards GDP release from the catalytic KRas4B, thus KRas4B activation. The accelerated activation cycle supports a positive feedback loop with allosteric signals communicating between the two Ras molecules and is the predominant, native function of SOS. SOS1 activation details may help drug discovery to inhibit Ras activation.
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Affiliation(s)
- Tsung-Jen Liao
- Cancer and Inflammation Program, Leidos Biomedical Research, Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, Maryland; Biophysics Program
| | - Hyunbum Jang
- Cancer and Inflammation Program, Leidos Biomedical Research, Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, Maryland
| | - David Fushman
- Biophysics Program; Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Organization, University of Maryland, College Park, Maryland
| | - Ruth Nussinov
- Cancer and Inflammation Program, Leidos Biomedical Research, Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, Maryland; Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
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26
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Ozdemir ES, Jang H, Gursoy A, Keskin O, Nussinov R. Arl2-Mediated Allosteric Release of Farnesylated KRas4B from Shuttling Factor PDEδ. J Phys Chem B 2018; 122:7503-7513. [PMID: 29961325 PMCID: PMC8087113 DOI: 10.1021/acs.jpcb.8b04347] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Proper localization of Ras proteins at the plasma membrane (PM) is crucial for their functions. To get to the PM, KRas4B and some other Ras family proteins bind to the PDEδ shuttling protein through their farnesylated hypervariable regions (HVRs). The docking of their farnesyl (and to a lesser extent geranylgeranyl) in the hydrophobic pocket of PDEδ's stabilizes the interaction. At the PM, guanosine 5'-triphosphate (GTP)-bound Arf-like protein 2 (Arl2) assists in the release of Ras from the PDEδ. However, exactly how is still unclear. Using all-atom molecular dynamics simulations, we unraveled the detailed mechanism of Arl2-mediated release of KRas4B, the most abundant oncogenic Ras isoform, from PDEδ. We simulated ternary Arl2-PDEδ-KRas4B HVR complexes and observed that Arl2 binding weakens the PDEδ-farnesylated HVR interaction. Our detailed analysis showed that allosteric changes (involving β6 of PDEδ and additional PDEδ residues) compress the hydrophobic PDEδ pocket and push the HVR out. Mutating PDEδ residues that mediate allosteric changes in PDEδ terminates the release process. Mutant Ras proteins are enriched in human cancers, with currently no drugs in the clinics. This mechanistic account may inspire efforts to develop drugs suppressing oncogenic KRas4B release.
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Affiliation(s)
- E. Sila Ozdemir
- Department of Chemical and Biological Engineering, Koc University, Istanbul 34450, Turkey
| | - Hyunbum Jang
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, Maryland 21702, United States
| | - Attila Gursoy
- Department of Computer Engineering, Koc University, Istanbul 34450, Turkey
- Research Center for Translational Medicine, Koc University, Istanbul 34450, Turkey
| | - Ozlem Keskin
- Department of Chemical and Biological Engineering, Koc University, Istanbul 34450, Turkey
- Research Center for Translational Medicine, Koc University, Istanbul 34450, Turkey
| | - Ruth Nussinov
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, Maryland 21702, United States
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
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Abstract
Identification of meaningful cluster modules of differential genes or representative biomarkers related to the stages of ovarian cancer (OC) is pivotal, which may help to detect mechanisms of OC progression and evaluate OC patients' prognosis.We downloaded gene expression data and the corresponding clinical information of OC patients from The Cancer Genome Atlas (TCGA) database, which included 379 ovarian cancer patients. Differentially expressed genes (DEGs) of OC patients between stages were picked out using R. There were 731 differential genes between ovarian cancer stage II and stage III (DEGs II-III) and 563 differential genes between ovarian cancer stage III and stage IV (DEGs III-IV), then we performed GO analysis and Kyoto Encyclopedia of Gene and Genome (KEGG) pathway analysis using Database for Annotation, Visualization and Integrated Discovery (DAVID). Moreover, CytoHubba was used to detect the top 20 hub genes in DEGs II-III and DEGs III-IV, followed Cytoscape with search tool for the retrieval of interacting genes (STRING) and MCODE plug-in was utilized to construct protein-protein interaction (PPI) modules of these genes. Three important coexpression modules of DEGs II-III and 3 more meaningful modules of DEGs III-IV were detected from PPI network using molecular complex detection (MCODE) tool. In addition, 5 hub genes in these stage-related DEGs modules with worse overall survival were selected, including COL3A1, COL1A1, COL1A2, KRAS, NRAS. This bioinformatics analysis demonstrated that stage-related prognostic DEGs, such as COL3A1, COL1A1, COL1A2, KRAS, and NRAS might play an unfavorable role in the development as well as metastasis of ovarian cancer. Furthermore, they need to be experimentally verified as a new biomarker to predict OC patient prognosis.
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Affiliation(s)
- Lili Yang
- Department of Obstetrics and Gynecology
| | | | | | - Ying Yue
- Department of Gynecological Oncology, The First Hospital of Jilin University, Changchun, China
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28
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Liu F, Yang X, Geng M, Huang M. Targeting ERK, an Achilles' Heel of the MAPK pathway, in cancer therapy. Acta Pharm Sin B 2018; 8:552-562. [PMID: 30109180 PMCID: PMC6089851 DOI: 10.1016/j.apsb.2018.01.008] [Citation(s) in RCA: 272] [Impact Index Per Article: 45.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2017] [Revised: 12/11/2017] [Accepted: 01/08/2018] [Indexed: 12/11/2022] Open
Abstract
The mitogen-activated protein kinases (MAPK) pathway, often known as the RAS-RAF-MEK-ERK signal cascade, functions to transmit upstream signals to its downstream effectors to regulate physiological process such as cell proliferation, differentiation, survival and death. As the most frequently mutated signaling pathway in human cancer, targeting the MAPK pathway has long been considered a promising strategy for cancer therapy. Substantial efforts in the past decades have led to the clinical success of BRAF and MEK inhibitors. However, the clinical benefits of these inhibitors are compromised by the frequently occurring acquired resistance due to cancer heterogeneity and genomic instability. This review briefly introduces the key protein kinases involved in this pathway as well as their activation mechanisms. We also generalize the correlations between mutations of MAPK members and human cancers, followed by a summarization of progress made on the development of small molecule MAPK kinases inhibitors. In particular, this review highlights the potential advantages of ERK inhibitors in overcoming resistance to upstream targets and proposes that targeting ERK kinase may hold a promising prospect for cancer therapy.
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Nussinov R, Zhang M, Tsai CJ, Jang H. Calmodulin and IQGAP1 activation of PI3Kα and Akt in KRAS, HRAS and NRAS-driven cancers. Biochim Biophys Acta Mol Basis Dis 2018; 1864:2304-2314. [DOI: 10.1016/j.bbadis.2017.10.032] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 10/24/2017] [Accepted: 10/27/2017] [Indexed: 02/06/2023]
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30
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Wang G, Zhang M, Jang H, Lu S, Lin S, Chen G, Nussinov R, Zhang J, Gaponenko V. Interaction of Calmodulin with the cSH2 Domain of the p85 Regulatory Subunit. Biochemistry 2018; 57:1917-1928. [PMID: 29494137 PMCID: PMC6454211 DOI: 10.1021/acs.biochem.7b01130] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Calmodulin (CaM) is a calcium sensor protein that directly interacts with the dual-specificity (lipid and protein) kinase PI3Kα through the SH2 domains of the p85 regulatory subunit. In adenocarcinomas, the CaM interaction removes the autoinhibition of the p110 catalytic subunit of PI3Kα, leading to activation of PI3Kα and promoting cell proliferation, survival, and migration. Here we demonstrate that the cSH2 domain of p85α engages its two CaM-binding motifs in the interaction with the N- and C-lobes of CaM as well as the flexible central linker, and our nuclear magnetic resonance experiments provide structural details. We show that in response to binding CaM, cSH2 exposes its tryptophan residue at the N-terminal region to the solvent. Because of the flexible nature of both CaM and cSH2, multiple binding modes of the interactions are possible. Binding of CaM to the cSH2 domain can help release the inhibition imposed on the p110 subunit, similar to the binding of the phosphorylated motif of RTK, or phosphorylated CaM (pCaM), to the SH2 domains. Amino acid sequence analysis shows that CaM-binding motifs are common in SH2 domains of non-RTKs. We speculate that CaM can also activate these kinases through similar mechanisms.
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Affiliation(s)
- Guanqiao Wang
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Ministry of Education, Shanghai Jiao-Tong University School of Medicine, Shanghai 200025, China
| | - Mingzhen Zhang
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, Maryland 21702, United States
| | - Hyunbum Jang
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, Maryland 21702, United States
| | - Shaoyong Lu
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Ministry of Education, Shanghai Jiao-Tong University School of Medicine, Shanghai 200025, China
| | - Shizhou Lin
- Obstetrics and Gynecology Hospital, Fudan University, Shanghai 200011, China
| | - Guoqiang Chen
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Ministry of Education, Shanghai Jiao-Tong University School of Medicine, Shanghai 200025, China
| | - Ruth Nussinov
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, Maryland 21702, United States
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Jian Zhang
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Ministry of Education, Shanghai Jiao-Tong University School of Medicine, Shanghai 200025, China
| | - Vadim Gaponenko
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois 60607, United States
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Li S, Jang H, Zhang J, Nussinov R. Raf-1 Cysteine-Rich Domain Increases the Affinity of K-Ras/Raf at the Membrane, Promoting MAPK Signaling. Structure 2018; 26:513-525.e2. [PMID: 29429878 PMCID: PMC8183739 DOI: 10.1016/j.str.2018.01.011] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 11/08/2017] [Accepted: 01/12/2018] [Indexed: 12/30/2022]
Abstract
K-Ras4B preferentially activates Raf-1. The high-affinity interaction of Ras-binding domain (RBD) of Raf with Ras was solved, but the relative position of Raf's cysteine-rich domain (CRD) in the Ras/Raf complex at the membrane and key question of exactly how it affects Raf signaling are daunting. We show that CRD stably binds anionic membranes inserting a positively charged loop into the amphipathic interface. Importantly, when in complex with Ras/RBD, covalently connected CRD presents the same membrane interaction mechanism, with CRD locating at the space between the RBD and membrane. To date, CRD's role was viewed in terms of stabilizing Raf-membrane interaction. Our observations argue for a key role in reducing Ras/RBD fluctuations at the membrane, thereby increasing Ras/RBD affinity. Even without K-Ras, via CRD, Raf-1 can recruit to the membrane; however, by reducing the Ras/RBD fluctuations and enhancing Ras/RBD affinity at the membrane, CRD promotes Raf's activation and MAPK signaling over other pathways.
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Affiliation(s)
- Shuai Li
- Department of Pathophysiology, Shanghai Universities E-Institute for Chemical Biology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Hyunbum Jang
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, USA
| | - Jian Zhang
- Department of Pathophysiology, Shanghai Universities E-Institute for Chemical Biology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Ruth Nussinov
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, 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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Yang IS, Kim S. Isoform specific gene expression analysis of KRAS in the prognosis of lung adenocarcinoma patients. BMC Bioinformatics 2018; 19:40. [PMID: 29504894 PMCID: PMC6389035 DOI: 10.1186/s12859-018-2011-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Background Aberrant mutations in KRAS play a critical role in tumor initiation and progression, and are a negative prognosis factor in lung adenocarcinoma (LUAD). Results Using genomic analysis for K-Ras isoforms (K-Ras4A and K-Ras4B) and large-scale multi-omics data, we inspected the overall survival (OS) and disease-free survival (DFS) of LUAD patients based on the abundance of transcript variants by analyzing RNA expression and somatic mutation data from The Cancer Genome Atlas (n = 516). The expression of the minor transcript K-Ras4A and its proportion were positively correlated with the presence of KRAS mutations in LUAD. We found that both K-Ras4A abundance measures (expression and proportion) have a strong association with poor OS (p = 0.0149 and p = 3.18E-3, respectively) and DFS (p = 3.03E-4 and p = 0.0237, respectively), but only in patients harboring KRAS mutations. A Cox regression analysis showed significant results in groups with low expression (hazard ratio (HR) = 2.533, 95% confidence interval (CI) = 1.380−4.651, p = 2.72E-3) and low proportion (HR = 2.549, 95% CI = 1.387−4.684, p = 2.58E-3) of K-Ras4A. Conclusions Based on the above results, we report the possible use of abundance measures for K-Ras4A for predicting the survival of LUAD patients with KRAS mutations. Electronic supplementary material The online version of this article (10.1186/s12859-018-2011-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- In Seok Yang
- Severance Biomedical Science Institute, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seoul, 03722, South Korea
| | - Sangwoo Kim
- Severance Biomedical Science Institute, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seoul, 03722, South Korea.
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33
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Nussinov R, Tsai CJ, Jang H. Is Nanoclustering essential for all oncogenic KRas pathways? Can it explain why wild-type KRas can inhibit its oncogenic variant? Semin Cancer Biol 2018; 54:114-120. [PMID: 29307569 DOI: 10.1016/j.semcancer.2018.01.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 12/19/2017] [Accepted: 01/04/2018] [Indexed: 10/18/2022]
Abstract
Membrane-anchored oncogenic KRas can dimerize, form nanoclusters, and signal through the MAPK (Raf/MEK/ERK) and PI3Kα/Akt/mTOR. Both pathways are needed in KRAS-driven proliferation. Here we ask: Is oncogenic KRas nanoclustering (or dimerization) essential for all KRas signaling pathways? Raf kinase domain dimerization, thus MAPK activation, requires KRas nanoclusters. By contrast, the PI3Kα heterodimer acts as a monomeric unit; thus, does PI3Kα activation and PI3Kα/Akt/mTOR signaling require nanoclustering? Further, calmodulin binds only to oncogenic KRas4B. Here we ask: Does calmodulin downregulate KRas4B cancer development as suggested early on, or promote it? We also ask: Why is oncogenic KRas4B the most abundant isoform? Does wild-type Ras indeed inhibit its oncogenic variants as data appeared to suggest? And related to the last question, why is wild-type KRas a more potent inhibitor of its oncogenic form than wild-type NRas of its oncogenic form? Resolving these cardinal questions, and others, such as how exactly does RASSF5 (NORE1A) act as tumor suppressor, and why Ras isoforms tend to occur in distinct cancer types are crucial for effective pharmacology. In this review, we take a nanoclustering/dimerization-centric outlook and show that many questions can be explained by simply considering Ras nanoclustering.
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Affiliation(s)
- Ruth Nussinov
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, USA; Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel.
| | - Chung-Jung Tsai
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, USA
| | - Hyunbum Jang
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, USA
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Zhang M, Jang H, Gaponenko V, Nussinov R. Phosphorylated Calmodulin Promotes PI3K Activation by Binding to the SH 2 Domains. Biophys J 2017; 113:1956-1967. [PMID: 29117520 PMCID: PMC5685777 DOI: 10.1016/j.bpj.2017.09.008] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 09/11/2017] [Accepted: 09/12/2017] [Indexed: 02/07/2023] Open
Abstract
How calmodulin (CaM) acts in KRAS-driven cancers is a vastly important question. CaM binds to and stimulates PI3Kα/Akt signaling, promoting cell growth and proliferation. Phosphorylation of CaM at Tyr99 (pY99) enhances PI3Kα activation. PI3Kα is a lipid kinase. It phosphorylates PIP2 to produce PIP3, to which Akt binds. PI3Kα has two subunits: the regulatory p85 and the catalytic p110. Here, exploiting explicit-solvent MD simulations we unveil key interactions between phosphorylated CaM (pCaM) and the two SH2 domains in the p85 subunit, confirm experimental observations, and uncover PI3Kα's mechanism of activation. pCaMs form strong and stable interactions with both nSH2 and cSH2 domains, with pY99 being the dominant contributor. Despite the high structural similarity between the two SH2 domains, we observe that nSH2 prefers an extended CaM conformation, whereas cSH2 prefers a collapsed conformation. Notably, collapsed CaM is observed after binding of an extended CaM to K-Ras4B. Thus, the more populated extended pCaM conformation targets nSH2 to release its autoinhibition of p110 catalytic sites. This executes the key activation step of PI3Kα. Independently, K-Ras4B allosterically activates p110. These events are at the cell membrane, which contributes to tighten the PI3Kα Ras binding domain/K-Ras4B interaction, to accomplish K-Ras4B allosteric activation, with a minor contribution from cSH2.
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Affiliation(s)
- Mingzhen Zhang
- Cancer and Inflammation Program, Leidos Biomedical Research, Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, Maryland
| | - Hyunbum Jang
- Cancer and Inflammation Program, Leidos Biomedical Research, Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, Maryland
| | - Vadim Gaponenko
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois
| | - Ruth Nussinov
- Cancer and Inflammation Program, Leidos Biomedical Research, Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, Maryland; Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
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Nussinov R, Jang H, Tsai CJ, Liao TJ, Li S, Fushman D, Zhang J. Intrinsic protein disorder in oncogenic KRAS signaling. Cell Mol Life Sci 2017; 74:3245-3261. [PMID: 28597297 PMCID: PMC11107717 DOI: 10.1007/s00018-017-2564-3] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 06/01/2017] [Indexed: 12/18/2022]
Abstract
How Ras, and in particular its most abundant oncogenic isoform K-Ras4B, is activated and signals in proliferating cells, poses some of the most challenging questions in cancer cell biology. In this paper, we ask how intrinsically disordered regions in K-Ras4B and its effectors help promote proliferative signaling. Conformational disorder allows spanning long distances, supports hinge motions, promotes anchoring in membranes, permits segments to fulfil multiple roles, and broadly is crucial for activation mechanisms and intensified oncogenic signaling. Here, we provide an overview illustrating some of the key mechanisms through which conformational disorder can promote oncogenesis, with K-Ras4B signaling serving as an example. We discuss (1) GTP-bound KRas4B activation through membrane attachment; (2) how farnesylation and palmitoylation can promote isoform functional specificity; (3) calmodulin binding and PI3K activation; (4) how Ras activates its RASSF5 cofactor, thereby stimulating signaling of the Hippo pathway and repressing proliferation; and (5) how intrinsically disordered segments in Raf help its attachment to the membrane and activation. Collectively, we provide the first inclusive review of the roles of intrinsic protein disorder in oncogenic Ras-driven signaling. We believe that a broad picture helps to grasp and formulate key mechanisms in Ras cancer biology and assists in therapeutic intervention.
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Affiliation(s)
- Ruth Nussinov
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, MD, 21702, USA.
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, 69978, Israel.
| | - Hyunbum Jang
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, MD, 21702, USA
| | - Chung-Jung Tsai
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, MD, 21702, USA
| | - Tsung-Jen Liao
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, MD, 21702, USA
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Organization, University of Maryland, College Park, MD, 20742, USA
| | - Shuai Li
- Department of Pathophysiology, Shanghai Universities E-Institute for Chemical Biology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai, 200025, China
| | - David Fushman
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Organization, University of Maryland, College Park, MD, 20742, USA
| | - Jian Zhang
- Department of Pathophysiology, Shanghai Universities E-Institute for Chemical Biology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai, 200025, China
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Jang H, Banerjee A, Chavan T, Gaponenko V, Nussinov R. Flexible-body motions of calmodulin and the farnesylated hypervariable region yield a high-affinity interaction enabling K-Ras4B membrane extraction. J Biol Chem 2017; 292:12544-12559. [PMID: 28623230 PMCID: PMC5535030 DOI: 10.1074/jbc.m117.785063] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 06/05/2017] [Indexed: 01/01/2023] Open
Abstract
In calmodulin (CaM)-rich environments, oncogenic KRAS plays a critical role in adenocarcinomas by promoting PI3K/Akt signaling. We previously proposed that at elevated calcium levels in cancer, CaM recruits PI3Kα to the membrane and extracts K-Ras4B from the membrane, organizing a K-Ras4B-CaM-PI3Kα ternary complex. CaM can thereby replace a missing receptor-tyrosine kinase signal to fully activate PI3Kα. Recent experimental data show that CaM selectively promotes K-Ras signaling but not of N-Ras or H-Ras. How CaM specifically targets K-Ras and how it extracts it from the membrane in KRAS-driven cancer is unclear. Obtaining detailed structural information for a CaM-K-Ras complex is still challenging. Here, using molecular dynamics simulations and fluorescence experiments, we observed that CaM preferentially binds unfolded K-Ras4B hypervariable regions (HVRs) and not α-helical HVRs. The interaction involved all three CaM domains including the central linker and both lobes. CaM specifically targeted the highly polybasic anchor region of the K-Ras4B HVR that stably wraps around CaM's acidic linker. The docking of the farnesyl group to the hydrophobic pockets located at both CaM lobes further enhanced CaM-HVR complex stability. Both CaM and K-Ras4B HVR are highly flexible molecules, suggesting that their interactions permit highly dynamic flexible-body motions. We, therefore, anticipate that the flexible-body interaction is required to extract K-Ras4B from the membrane, as conformational plasticity enables CaM to orient efficiently to the polybasic HVR anchor, which is partially diffused into the liquid-phase membrane. Our structural model of the CaM-K-Ras4B HVR association provides plausible clues to CaM's regulatory action in PI3Kα activation involving the ternary complex in cell proliferation signaling by oncogenic K-Ras.
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Affiliation(s)
- Hyunbum Jang
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, NCI-Frederick, Frederick, Maryland 21702
| | - Avik Banerjee
- Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois 60607
| | - Tanmay Chavan
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California 94305
| | - Vadim Gaponenko
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois 60607.
| | - Ruth Nussinov
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, NCI-Frederick, Frederick, Maryland 21702; Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel.
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Muratcioglu S, Jang H, Gursoy A, Keskin O, Nussinov R. PDEδ Binding to Ras Isoforms Provides a Route to Proper Membrane Localization. J Phys Chem B 2017; 121:5917-5927. [PMID: 28540724 PMCID: PMC7891760 DOI: 10.1021/acs.jpcb.7b03035] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
To signal, Ras isoforms must be enriched at the plasma membrane (PM). It was suggested that phosphodiesterase-δ (PDEδ) can bind and shuttle some farnesylated Ras isoforms to the PM, but not all. Among these, interest focused on K-Ras4B, the most abundant oncogenic Ras isoform. To study PDEδ/Ras interactions, we modeled and simulated the PDEδ/K-Ras4B complex. We obtained structures, which were similar to two subsequently determined crystal structures. We next modeled and simulated complexes of PDEδ with the farnesylated hypervariable regions of K-Ras4A and N-Ras. Earlier data suggested that PDEδ extracts K-Ras4B and N-Ras from the PM, but surprisingly not K-Ras4A. Earlier analysis of the crystal structures advanced that the presence of large/charged residues adjacent to the farnesylated site precludes the PDEδ interaction. Here, we show that PDEδ can bind to farnesylated K-Ras4A and N-Ras like K-Ras4B, albeit not as strongly. This weaker binding, coupled with the stronger anchoring of K-Ras4A in the membrane (but not of electrostatically neutral N-Ras), can explain the observation why PDEδ is unable to effectively extract K-Ras4A. We thus propose that farnesylated Ras isoforms can bind PDEδ to fulfill the required PM enrichment, and argue that the different environments, PM versus solution, can resolve apparently puzzling Ras observations. These are novel insights that would not be expected based on the crystal structures alone, which provide an elegant rationale for previously puzzling observations of the differential effects of PDEδ on farnesylated Ras family proteins.
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Affiliation(s)
- Serena Muratcioglu
- Department of Chemical and Biological Engineering, Koc University, Istanbul 34450, Turkey
| | - Hyunbum Jang
- Cancer and Inflammation Program, National Cancer Institute at Frederick and Basic Science Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research Inc., Frederick, Maryland 21702, United States
| | - Attila Gursoy
- Department of Computer Engineering, Koc University, Istanbul 34450, Turkey
| | - Ozlem Keskin
- Department of Chemical and Biological Engineering, Koc University, Istanbul 34450, Turkey
| | - Ruth Nussinov
- Cancer and Inflammation Program, National Cancer Institute at Frederick and Basic Science Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research Inc., Frederick, Maryland 21702, United States
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
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Computational Modeling Reveals that Signaling Lipids Modulate the Orientation of K-Ras4A at the Membrane Reflecting Protein Topology. Structure 2017; 25:679-689.e2. [PMID: 28286004 DOI: 10.1016/j.str.2017.02.007] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2016] [Revised: 01/18/2017] [Accepted: 02/16/2017] [Indexed: 12/17/2022]
Abstract
The structural, dynamical, and functional characterization of the small GTPase K-Ras has become a research area of intense focus due to its high occurrence in human cancers. Ras proteins are only fully functional when they interact with the plasma membrane. Here we present all-atom molecular dynamics simulations (totaling 5.8 μs) to investigate the K-Ras4A protein at membranes that contain anionic lipids (phosphatidyl serine or phosphatidylinositol bisphosphate). We find that similarly to the homologous and highly studied K-Ras4B, K-Ras4A prefers a few distinct orientations at the membrane. Remarkably, the protein surface charge and certain lipids can strongly modulate the orientation preference. In a novel analysis, we reveal that the electrostatic interaction (attraction but also repulsion) between the protein's charged residues and anionic lipids determines the K-Ras4A orientation, but that this is also influenced by the topology of the protein, reflecting the geometry of its surfaces.
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Nussinov R, Wang G, Tsai CJ, Jang H, Lu S, Banerjee A, Zhang J, Gaponenko V. Calmodulin and PI3K Signaling in KRAS Cancers. Trends Cancer 2017; 3:214-224. [PMID: 28462395 PMCID: PMC5408465 DOI: 10.1016/j.trecan.2017.01.007] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Calmodulin (CaM) uniquely promotes signaling of oncogenic K-Ras; but not N-Ras or H-Ras. How CaM interacts with K-Ras and how this stimulates cell proliferation are among the most challenging questions in KRAS-driven cancers. Earlier data pointed to formation of a ternary complex consisting of K-Ras, PI3Kα and CaM. Recent data point to phosphorylated CaM binding to the SH2 domains of the p85 subunit of PI3Kα and activating it. Modeling suggests that the high affinity interaction between the phosphorylated CaM tyrosine motif and PI3Kα, can promote full PI3Kα activation by oncogenic K-Ras. Our up-to-date review discusses CaM's role in PI3K signaling at the membrane in KRAS-driven cancers. This is significant since it may help development of K-Ras-specific pharmacology.
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Affiliation(s)
- Ruth Nussinov
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, U.S.A
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Guanqiao Wang
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Children’s Medical Center, Shanghai Jiao Tong University, School of Medicine, Shanghai, 200127, China
| | - Chung-Jung Tsai
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, U.S.A
| | - Hyunbum Jang
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, U.S.A
| | - Shaoyong Lu
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Children’s Medical Center, Shanghai Jiao Tong University, School of Medicine, Shanghai, 200127, China
| | - Avik Banerjee
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, IL 60607, U.S.A
| | - Jian Zhang
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Children’s Medical Center, Shanghai Jiao Tong University, School of Medicine, Shanghai, 200127, China
| | - Vadim Gaponenko
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, IL 60607, U.S.A
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Liao TJ, Jang H, Tsai CJ, Fushman D, Nussinov R. The dynamic mechanism of RASSF5 and MST kinase activation by Ras. Phys Chem Chem Phys 2017; 19:6470-6480. [PMID: 28197608 PMCID: PMC5381522 DOI: 10.1039/c6cp08596b] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
As a tumor suppressor, RASSF5 (NORE1A) activates MST1/2 thereby modulating the Hippo pathway. Structurally, activation involves RASSF5 and MST1/2 swapping their SARAH domains to form a SARAH heterodimer. This exposes the MST1/2 kinase domain which homodimerizes, leading to trans-autophosphorylation. The SARAH-SARAH interaction shifts RASSF5 away from its autoinhibited state and relieves MST1/2 autoinhibition. Separate crystal structures are available for the RA (Ras association) domain and SARAH dimer, where SARAH is a long straight α-helix. Using all-atom molecular dynamics simulations, we modeled the RASSF5 RA with a covalently connected SARAH to elucidate the dynamic mechanism of how SARAH mediates between autoinhibition and Ras triggered-activation. Our results show that in inactive RASSF5 the RA domain retains SARAH, yielding a self-associated conformation in which SARAH is in a kinked α-helical motif that increases the binding interface. When RASSF5 binds K-Ras4B-GTP, the equilibrium shifts toward SARAH's interacting with MST. Since the RA/SARAH affinity is relatively low, whereas that of the SARAH heterodimer is in the nM range, we suggest that RASSF5 exerts its tumor suppressor action through competition with other Ras effectors for Ras effector binding site, as well as coincidentally its recruitment to the membrane to help MST activation. Thus, SARAH plays a key role in RASSF5's tumor suppression action by linking the two major pathways in tumor cell proliferation: Ras and the MAPK (tumor cell proliferation-promoting) pathway, and the Hippo (tumor cell proliferation-suppressing) pathway.
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Affiliation(s)
- Tsung-Jen Liao
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, USA. and Biophysics Program, Center for Biomolecular Structure and Organization, University of Maryland, College Park, MD 20742, USA
| | - Hyunbum Jang
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, USA.
| | - Chung-Jung Tsai
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, USA.
| | - David Fushman
- Biophysics Program, Center for Biomolecular Structure and Organization, University of Maryland, College Park, MD 20742, USA and Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Organization, University of Maryland, College Park, MD 20742, USA
| | - Ruth Nussinov
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, USA. and Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
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Lu S, Jang H, Gu S, Zhang J, Nussinov R. Drugging Ras GTPase: a comprehensive mechanistic and signaling structural view. Chem Soc Rev 2016; 45:4929-52. [PMID: 27396271 PMCID: PMC5021603 DOI: 10.1039/c5cs00911a] [Citation(s) in RCA: 142] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ras proteins are small GTPases, cycling between inactive GDP-bound and active GTP-bound states. Through these switches they regulate signaling that controls cell growth and proliferation. Activating Ras mutations are associated with approximately 30% of human cancers, which are frequently resistant to standard therapies. Over the past few years, structural biology and in silico drug design, coupled with improved screening technology, led to a handful of promising inhibitors, raising the possibility of drugging Ras proteins. At the same time, the invariable emergence of drug resistance argues for the critical importance of additionally honing in on signaling pathways which are likely to be involved. Here we overview current advances in Ras structural knowledge, including the conformational dynamic of full-length Ras in solution and at the membrane, therapeutic inhibition of Ras activity by targeting its active site, allosteric sites, and Ras-effector protein-protein interfaces, Ras dimers, the K-Ras4B/calmodulin/PI3Kα trimer, and targeting Ras with siRNA. To mitigate drug resistance, we propose signaling pathways that can be co-targeted along with Ras and explain why. These include pathways leading to the expression (or activation) of YAP1 and c-Myc. We postulate that these and Ras signaling pathways, MAPK/ERK and PI3K/Akt/mTOR, act independently and in corresponding ways in cell cycle control. The structural data are instrumental in the discovery and development of Ras inhibitors for treating RAS-driven cancers. Together with the signaling blueprints through which drug resistance can evolve, this review provides a comprehensive and innovative master plan for tackling mutant Ras proteins.
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Affiliation(s)
- Shaoyong Lu
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Children’s Medical Center, Shanghai Jiao Tong University, School of Medicine, Shanghai, 200127, China
| | - Hyunbum Jang
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory, National Cancer Institute, Frederick, MD 21702, U.S.A
| | - Shuo Gu
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Children’s Medical Center, Shanghai Jiao Tong University, School of Medicine, Shanghai, 200127, China
| | - Jian Zhang
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Children’s Medical Center, Shanghai Jiao Tong University, School of Medicine, Shanghai, 200127, China
| | - Ruth Nussinov
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory, National Cancer Institute, Frederick, MD 21702, U.S.A
- Department of Human Genetics and Molecular Medicine, Sackler School of Medicine, Sackler Institute of Molecular Medicine, Tel Aviv University, Tel Aviv 69978, Israel
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Affiliation(s)
- Ruth Nussinov
- Basic Science Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Cancer and Inflammation Program, National Cancer Institute at Frederick, Frederick, MD 21702, U.S.A
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Chung-Jung Tsai
- Basic Science Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Cancer and Inflammation Program, National Cancer Institute at Frederick, Frederick, MD 21702, U.S.A
| | - Hyunbum Jang
- Basic Science Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Cancer and Inflammation Program, National Cancer Institute at Frederick, Frederick, MD 21702, U.S.A
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