1
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Parise A, Cresca S, Magistrato A. Molecular dynamics simulations for the structure-based drug design: targeting small-GTPases proteins. Expert Opin Drug Discov 2024; 19:1259-1279. [PMID: 39105536 DOI: 10.1080/17460441.2024.2387856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Accepted: 07/30/2024] [Indexed: 08/07/2024]
Abstract
INTRODUCTION Molecular Dynamics (MD) simulations can support mechanism-based drug design. Indeed, MD simulations by capturing biomolecule motions at finite temperatures can reveal hidden binding sites, accurately predict drug-binding poses, and estimate the thermodynamics and kinetics, crucial information for drug discovery campaigns. Small-Guanosine Triphosphate Phosphohydrolases (GTPases) regulate a cascade of signaling events, that affect most cellular processes. Their deregulation is linked to several diseases, making them appealing drug targets. The broad roles of small-GTPases in cellular processes and the recent approval of a covalent KRas inhibitor as an anticancer agent renewed the interest in targeting small-GTPase with small molecules. AREA COVERED This review emphasizes the role of MD simulations in elucidating small-GTPase mechanisms, assessing the impact of cancer-related variants, and discovering novel inhibitors. EXPERT OPINION The application of MD simulations to small-GTPases exemplifies the role of MD simulations in the structure-based drug design process for challenging biomolecular targets. Furthermore, AI and machine learning-enhanced MD simulations, coupled with the upcoming power of quantum computing, are promising instruments to target elusive small-GTPases mutations and splice variants. This powerful synergy will aid in developing innovative therapeutic strategies associated to small-GTPases deregulation, which could potentially be used for personalized therapies and in a tissue-agnostic manner to treat tumors with mutations in small-GTPases.
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Affiliation(s)
- Angela Parise
- Consiglio Nazionale delle Ricerche (CNR) - Istituto Officina dei Materiali (IOM), c/o International School for Advanced Studies (SISSA), Trieste, Italy
| | - Sofia Cresca
- Consiglio Nazionale delle Ricerche (CNR) - Istituto Officina dei Materiali (IOM), c/o International School for Advanced Studies (SISSA), Trieste, Italy
| | - Alessandra Magistrato
- Consiglio Nazionale delle Ricerche (CNR) - Istituto Officina dei Materiali (IOM), c/o International School for Advanced Studies (SISSA), Trieste, Italy
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2
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Ren H, Lee AA, Lew LJN, DeGrandchamp JB, Groves JT. Positive feedback in Ras activation by full-length SOS arises from autoinhibition release mechanism. Biophys J 2024; 123:3295-3303. [PMID: 39021073 PMCID: PMC11480760 DOI: 10.1016/j.bpj.2024.07.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2024] [Revised: 06/08/2024] [Accepted: 07/12/2024] [Indexed: 07/20/2024] Open
Abstract
Signaling through the Ras-MAPK pathway can exhibit switch-like activation, which has been attributed to the underlying positive feedback and bimodality in the activation of RasGDP to RasGTP by SOS. SOS contains both catalytic and allosteric Ras binding sites, and a common assumption is that allosteric activation selectively by RasGTP provides the mechanism of positive feedback. However, recent single-molecule studies have revealed that SOS catalytic rates are independent of the nucleotide state of Ras in the allosteric binding site, raising doubt about this as a positive feedback mechanism. Here, we perform detailed kinetic analyses of receptor-mediated recruitment of full-length SOS to the membrane while simultaneously monitoring its catalytic activation of Ras. These results, along with kinetic modeling, expose the autoinhibition release step in SOS, rather than either recruitment or allosteric activation, as the underlying mechanism giving rise to positive feedback in Ras activation.
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Affiliation(s)
- He Ren
- Department of Chemistry, University of California Berkeley, Berkeley, California
| | - Albert A Lee
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, California
| | - L J Nugent Lew
- Department of Chemistry, University of California Berkeley, Berkeley, California
| | | | - Jay T Groves
- Department of Chemistry, University of California Berkeley, Berkeley, California; Division of Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, California.
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3
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Lin Y, Ramelot TA, Senyuz S, Gursoy A, Jang H, Nussinov R, Keskin O, Zheng Y. Tumor-derived RHOA mutants interact with effectors in the GDP-bound state. Nat Commun 2024; 15:7176. [PMID: 39169042 PMCID: PMC11339415 DOI: 10.1038/s41467-024-51445-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 08/07/2024] [Indexed: 08/23/2024] Open
Abstract
RHOA mutations are found at diverse residues in various cancer types, implying mutation- and cell-specific mechanisms of tumorigenesis. Here, we focus on the underlying mechanisms of two gain-of-function RHOA mutations, A161P and A161V, identified in adult T-cell leukemia/lymphoma. We find that RHOAA161P and RHOAA161V are both fast-cycling mutants with increased guanine nucleotide dissociation/association rates compared with RHOAWT and show reduced GTP-hydrolysis activity. Crystal structures reveal an altered nucleotide association in RHOAA161P and an open nucleotide pocket in RHOAA161V. Both mutations perturb the dynamic properties of RHOA switch regions and shift the conformational landscape important for RHOA activity, as shown by 31P NMR and molecular dynamics simulations. Interestingly, RHOAA161P and RHOAA161V can interact with effectors in the GDP-bound state. 1H-15N HSQC NMR spectra support the existence of an active population in RHOAA161V-GDP. The distinct interaction mechanisms resulting from the mutations likely favor an RHOAWT-like "ON" conformation, endowing GDP-bound state effector binding activity.
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Affiliation(s)
- Yuan Lin
- Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
| | - Theresa A Ramelot
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Simge Senyuz
- Computational Sciences and Engineering, Koc University, Rumelifeneri Yolu, Istanbul, Turkey
| | - Attila Gursoy
- Department of Computer Engineering, Koc Univeristy, Rumelifeneri Yolu, Istanbul, Turkey
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Cancer Innovation Laboratory, National Cancer Institute, Frederick, MD, USA
| | - Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Cancer Innovation Laboratory, National Cancer Institute, Frederick, MD, USA
| | - Ozlem Keskin
- Department of Chemical and Biological Engineering, Koc Univeristy, Rumelifeneri Yolu, Istanbul, Turkey
| | - Yi Zheng
- Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
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4
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Thines L, Jang H, Li Z, Sayedyahossein S, Maloney R, Nussinov R, Sacks DB. Disruption of Ca 2+/calmodulin:KSR1 interaction lowers ERK activation. Protein Sci 2024; 33:e4982. [PMID: 38591710 PMCID: PMC11002989 DOI: 10.1002/pro.4982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 02/22/2024] [Accepted: 03/16/2024] [Indexed: 04/10/2024]
Abstract
KSR1, a key scaffold protein for the MAPK pathway, facilitates ERK activation upon growth factor stimulation. We recently demonstrated that KSR1 binds the Ca2+-binding protein calmodulin (CaM), thereby providing an intersection between KSR1-mediated and Ca2+ signaling. In this study, we set out to generate a KSR1 point mutant with reduced Ca2+/CaM binding in order to unravel the functional implications of their interaction. To do so, we solved the structural determinants of complex formation. Using purified fragments of KSR1, we showed that Ca2+/CaM binds to the CA3 domain of KSR1. We then used in silico molecular modeling to predict contact residues for binding. This approach identified two possible modes of interaction: (1) binding of extended Ca2+/CaM to a globular conformation of KSR1-CA3 via electrostatic interactions or (2) binding of collapsed Ca2+/CaM to α-helical KSR1-CA3 via hydrophobic interactions. Experimentally, site-directed mutagenesis of the predicted contact residues for the two binding models favored that where collapsed Ca2+/CaM binds to the α-helical conformation of KSR1-CA3. Importantly, replacing KSR1-Phe355 with Asp reduces Ca2+/CaM binding by 76%. The KSR1-F355D mutation also significantly impairs the ability of EGF to activate ERK, which reveals that Ca2+/CaM binding promotes KSR1-mediated MAPK signaling. This work, by uncovering structural insight into the binding of KSR1 to Ca2+/CaM, identifies a KSR1 single-point mutant as a bioreagent to selectively study the crosstalk between Ca2+ and KSR1-mediated signaling.
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Affiliation(s)
- Louise Thines
- Department of Laboratory MedicineNational Institutes of HealthBethesdaMarylandUSA
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Cancer Innovation LaboratoryNational Cancer InstituteFrederickMarylandUSA
| | - Zhigang Li
- Department of Laboratory MedicineNational Institutes of HealthBethesdaMarylandUSA
| | - Samar Sayedyahossein
- Department of Laboratory MedicineNational Institutes of HealthBethesdaMarylandUSA
| | - Ryan Maloney
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Cancer Innovation LaboratoryNational Cancer InstituteFrederickMarylandUSA
| | - Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Cancer Innovation LaboratoryNational Cancer InstituteFrederickMarylandUSA
- Department of Human Molecular Genetics and BiochemistrySackler School of Medicine, Tel Aviv UniversityTel AvivIsrael
| | - David B. Sacks
- Department of Laboratory MedicineNational Institutes of HealthBethesdaMarylandUSA
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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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Bhadhadhara K, Jani V, Koulgi S, Sonavane U, Joshi R. Studying early structural changes in SOS1 mediated KRAS activation mechanism. Curr Res Struct Biol 2023; 7:100115. [PMID: 38188543 PMCID: PMC10765296 DOI: 10.1016/j.crstbi.2023.100115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 11/28/2023] [Accepted: 11/29/2023] [Indexed: 01/09/2024] Open
Abstract
KRAS activation is known to be modulated by a guanine nucleotide exchange factor (GEF), namely, Son of Sevenless1 (SOS1). SOS1 facilitates the exchange of GDP to GTP thereby leading to activation of KRAS. The binding of GDP/GTP to KRAS at the REM/allosteric site of SOS1 regulates the activation of KRAS at CDC25/catalytic site by facilitating its exchange. Different aspects of the allosteric activation of KRAS through SOS1 are still being explored. To understand the SOS1 mediated activation of KRAS, molecular dynamics simulations for a total of nine SOS1 complexes (KRAS-SOS1-KRAS) were performed. These nine systems comprised different combinations of KRAS-bound nucleotides (GTP/GDP) at REM and CDC25 sites of SOS1. Various conformational and thermodynamic parameters were analyzed for these simulation systems. MMPBSA free energy analysis revealed that binding at CDC25 site of SOS1 was significantly low for GDP-bound KRAS as compared to that of GTP-bound KRAS. It was observed that presence of either GDP/GTP bound KRAS at the REM site of SOS1 affected the activation related changes in the KRAS present at CDC25 site. The conformational changes at the catalytic site of SOS1 resulting from GDP/GTP-bound KRAS at the allosteric changes may hint at KRAS activation through different pathways (slow/fast/rare). The allosteric effect on activation of KRAS at CDC25 site may be due to conformations adopted by switch-I, switch-II, beta2 regions of KRAS at REM site. The effect of structural rearrangements occurring at allosteric KRAS may have led to increased interactions between SOS1 and KRAS at both the sites. The SOS1 residues involved in these important interactions with KRAS at the REM site were R694, S732 and K735. Whereas the ones interacting with KRAS at CDC25 site were S807, W809 and K814. This may suggest the crucial role of these residues in guiding the allosteric activation of KRAS at CDC25 site. The conformational shifts observed in the switch-I, switch-II and alpha3 regions of KRAS at CDC25 site may be attributed to be a part of allosteric activation. The binding affinities, interacting residues and conformational dynamics may provide an insight into development of inhibitors targeting the SOS1 mediated KRAS activation.
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Affiliation(s)
- Kirti Bhadhadhara
- High Performance Computing-Medical & Bioinformatics Applications Group, Centre for Development of Advanced Computing (C-DAC), Innovation Park, Panchawati, Pashan, Pune, 411008, India
| | - Vinod Jani
- High Performance Computing-Medical & Bioinformatics Applications Group, Centre for Development of Advanced Computing (C-DAC), Innovation Park, Panchawati, Pashan, Pune, 411008, India
| | - Shruti Koulgi
- High Performance Computing-Medical & Bioinformatics Applications Group, Centre for Development of Advanced Computing (C-DAC), Innovation Park, Panchawati, Pashan, Pune, 411008, India
| | - Uddhavesh Sonavane
- High Performance Computing-Medical & Bioinformatics Applications Group, Centre for Development of Advanced Computing (C-DAC), Innovation Park, Panchawati, Pashan, Pune, 411008, India
| | - Rajendra Joshi
- High Performance Computing-Medical & Bioinformatics Applications Group, Centre for Development of Advanced Computing (C-DAC), Innovation Park, Panchawati, Pashan, Pune, 411008, India
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7
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Liu Y, Zhang M, Jang H, Nussinov R. Higher-order interactions of Bcr-Abl can broaden chronic myeloid leukemia (CML) drug repertoire. Protein Sci 2023; 32:e4504. [PMID: 36369657 PMCID: PMC9795542 DOI: 10.1002/pro.4504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 10/31/2022] [Accepted: 11/06/2022] [Indexed: 11/14/2022]
Abstract
Bcr-Abl, a nonreceptor tyrosine kinase, is associated with leukemias, especially chronic myeloid leukemia (CML). Deletion of Abl's N-terminal region, to which myristoyl is linked, renders the Bcr-Abl fusion oncoprotein constitutively active. The substitution of Abl's N-terminal region by Bcr enables Bcr-Abl oligomerization. Oligomerization is critical: it promotes clustering on the membrane, which is essential for potent MAPK signaling and cell proliferation. Here we decipher the Bcr-Abl specific, step-by-step oligomerization process, identify a specific packing surface, determine exactly how the process is structured and identify its key elements. Bcr's coiled coil (CC) domain at the N-terminal controls Bcr-Abl oligomerization. Crystallography validated oligomerization via Bcr-Abl dimerization between two Bcr CC domains, with tetramerization via tight packing between two binary assemblies. However, the structural principles guiding Bcr CC domain oligomerization are unknown, hindering mechanistic understanding and drugs exploiting it. Using molecular dynamics (MD) simulations, we determine that the binary complex of the Bcr CC domain serves as a basic unit in the quaternary complex providing a specific surface for dimer-dimer packing and higher-order oligomerization. We discover that the small α1-helix is the key. In the binary assembly, the helix forms interchain aromatic dimeric packing, and in the quaternary assembly, it contributes to the specific dimer-dimer packing. Our mechanism is supported by the experimental literature. It offers the key elements controlling this process which can expand the drug discovery strategy, including by Bcr CC-derived peptides, and candidate residues for small covalent drugs, toward quenching oligomerization, supplementing competitive and allosteric tyrosine kinase inhibitors.
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Affiliation(s)
- Yonglan Liu
- Cancer Innovation LaboratoryNational Cancer InstituteFrederickMarylandUSA
| | - Mingzhen Zhang
- Computational Structural Biology SectionFrederick National Laboratory for Cancer ResearchFrederickMarylandUSA
| | - Hyunbum Jang
- Computational Structural Biology SectionFrederick National Laboratory for Cancer ResearchFrederickMarylandUSA
| | - Ruth Nussinov
- Computational Structural Biology SectionFrederick National Laboratory for Cancer ResearchFrederickMarylandUSA,Department of Human Molecular Genetics and BiochemistrySackler School of Medicine, Tel Aviv UniversityTel AvivIsrael
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8
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Pálfy G, Menyhárd DK, Ákontz‐Kiss H, Vida I, Batta G, Tőke O, Perczel A. The Importance of Mg 2+ -Free State in Nucleotide Exchange of Oncogenic K-Ras Mutants. Chemistry 2022; 28:e202201449. [PMID: 35781716 PMCID: PMC9804424 DOI: 10.1002/chem.202201449] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Indexed: 01/05/2023]
Abstract
For efficient targeting of oncogenic K-Ras interaction sites, a mechanistic picture of the Ras-cycle is necessary. Herein, we used NMR relaxation techniques and molecular dynamics simulations to decipher the role of slow dynamics in wild-type and three oncogenic P-loop mutants of K-Ras. Our measurements reveal a dominant two-state conformational exchange on the ms timescale in both GDP- and GTP-bound K-Ras. The identified low-populated higher energy state in GDP-loaded K-Ras has a conformation reminiscent of a nucleotide-bound/Mg2+ -free state characterized by shortened β2/β3-strands and a partially released switch-I region preparing K-Ras for the interaction with the incoming nucleotide exchange factor and subsequent reactivation. By providing insight into mutation-specific differences in K-Ras structural dynamics, our systematic analysis improves our understanding of prolonged K-Ras signaling and may aid the development of allosteric inhibitors targeting nucleotide exchange in K-Ras.
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Affiliation(s)
- Gyula Pálfy
- Laboratory of Structural Chemistry and BiologyInstitute of ChemistryEötvös Loránd University1/a Pázmány Péter stny.Budapest1117Hungary,MTA-ELTE Protein Modeling Research GroupEötvös Loránd Research Network (ELKH)1/a Pázmány Péter stny.Budapest1117Hungary
| | - Dóra K. Menyhárd
- MTA-ELTE Protein Modeling Research GroupEötvös Loránd Research Network (ELKH)1/a Pázmány Péter stny.Budapest1117Hungary
| | - Hanna Ákontz‐Kiss
- Laboratory of Structural Chemistry and BiologyInstitute of ChemistryEötvös Loránd University1/a Pázmány Péter stny.Budapest1117Hungary,Hevesy György PhD School of ChemistryEötvös Loránd University1/a Pázmány Péter stny.Budapest1117Hungary
| | - István Vida
- Laboratory of Structural Chemistry and BiologyInstitute of ChemistryEötvös Loránd University1/a Pázmány Péter stny.Budapest1117Hungary,Hevesy György PhD School of ChemistryEötvös Loránd University1/a Pázmány Péter stny.Budapest1117Hungary
| | - Gyula Batta
- Structural Biology Research GroupDepartment of Organic ChemistryUniversity of Debrecen1 Egyetem térDebrecen4032Hungary
| | - Orsolya Tőke
- Laboratory for NMR SpectroscopyResearch Centre for Natural Sciences (RCNS)2 Magyar tudósok körútjaBudapest1117Hungary
| | - András Perczel
- Laboratory of Structural Chemistry and BiologyInstitute of ChemistryEötvös Loránd University1/a Pázmány Péter stny.Budapest1117Hungary,MTA-ELTE Protein Modeling Research GroupEötvös Loránd Research Network (ELKH)1/a Pázmány Péter stny.Budapest1117Hungary
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9
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Nussinov R, Zhang M, Maloney R, Liu Y, Tsai CJ, Jang H. Allostery: Allosteric Cancer Drivers and Innovative Allosteric Drugs. J Mol Biol 2022; 434:167569. [PMID: 35378118 PMCID: PMC9398924 DOI: 10.1016/j.jmb.2022.167569] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 03/11/2022] [Accepted: 03/25/2022] [Indexed: 01/12/2023]
Abstract
Here, we discuss the principles of allosteric activating mutations, propagation downstream of the signals that they prompt, and allosteric drugs, with examples from the Ras signaling network. We focus on Abl kinase where mutations shift the landscape toward the active, imatinib binding-incompetent conformation, likely resulting in the high affinity ATP outcompeting drug binding. Recent pharmacological innovation extends to allosteric inhibitor (GNF-5)-linked PROTAC, targeting Bcr-Abl1 myristoylation site, and broadly, allosteric heterobifunctional degraders that destroy targets, rather than inhibiting them. Designed chemical linkers in bifunctional degraders can connect the allosteric ligand that binds the target protein and the E3 ubiquitin ligase warhead anchor. The physical properties and favored conformational state of the engineered linker can precisely coordinate the distance and orientation between the target and the recruited E3. Allosteric PROTACs, noncompetitive molecular glues, and bitopic ligands, with covalent links of allosteric ligands and orthosteric warheads, increase the effective local concentration of productively oriented and placed ligands. Through covalent chemical or peptide linkers, allosteric drugs can collaborate with competitive drugs, degrader anchors, or other molecules of choice, driving innovative drug discovery.
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Affiliation(s)
- Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA; Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel.
| | - Mingzhen Zhang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA
| | - Ryan Maloney
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA
| | - Yonglan Liu
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA
| | - Chung-Jung Tsai
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA
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10
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Liu Y, Jang H, Zhang M, Tsai CJ, Maloney R, Nussinov R. The structural basis of BCR-ABL recruitment of GRB2 in chronic myelogenous leukemia. Biophys J 2022; 121:2251-2265. [PMID: 35651316 PMCID: PMC9279350 DOI: 10.1016/j.bpj.2022.05.030] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 04/24/2022] [Accepted: 05/20/2022] [Indexed: 11/21/2022] Open
Abstract
BCR-ABL drives chronic myeloid leukemia (CML). BCR binding to GRB2 transduces signaling via the Ras/MAPK pathway. Despite considerable data confirming the binding, molecular-level understanding of exactly how the two proteins interact, and, especially, what are the determinants of the specificity of the SH2GRB2 domain-phosphorylated BCR (pBCR) recognition are still open questions. Yet, this is vastly important for understanding binding selectivity, and for predicting the phosphorylated receptors, or peptides, that are likely to bind. Here, we uncover these determinants and ascertain to what extent they relate to the affinity of the interaction. Toward this end, we modeled the complexes of the pBCR and SH2GRB2 and other pY/Y-peptide-SH2 complexes and compared their specificity and affinity. We observed that pBCR's 176FpYVNV180 motif is favorable and specific to SH2GRB2, similar to pEGFR, but not other complexes. SH2GRB2 contains two binding pockets: pY-binding recognition pocket triggers binding, and the specificity pocket whose interaction is governed by N179 in pBCR and W121 in SH2GRB2. Our proposed motif with optimal affinity to SH2GRB2 is E/D-pY-E/V-N-I/L. Collectively, we provide the structural basis of BCR-ABL recruitment of GRB2, outline its specificity hallmarks, and delineate a blueprint for prediction of BCR-binding scaffolds and for therapeutic peptide design.
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Affiliation(s)
- Yonglan Liu
- Cancer Innovation Laboratory, National Cancer Institute, Frederick, Maryland
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research, Frederick, Maryland
| | - Mingzhen Zhang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research, Frederick, Maryland
| | - Chung-Jung Tsai
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research, Frederick, Maryland
| | - Ryan Maloney
- Cancer Innovation Laboratory, National Cancer Institute, Frederick, Maryland
| | - Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research, Frederick, Maryland; Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
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11
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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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12
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He X, Du K, Wang Y, Fan J, Li M, Ni D, Lu S, Bian X, Liu Y. Autopromotion of K-Ras4B Feedback Activation Through an SOS-Mediated Long-Range Allosteric Effect. Front Mol Biosci 2022; 9:860962. [PMID: 35463958 PMCID: PMC9023742 DOI: 10.3389/fmolb.2022.860962] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 03/01/2022] [Indexed: 12/14/2022] Open
Abstract
The Ras-specific guanine nucleotide exchange factors Son of Sevenless (SOS) regulates Ras activation by converting inactive GDP-bound to active GTP-bound states. The catalytic activity of Ras is further allosterically regulated by GTP-Ras bound to a distal site through a positive feedback loop. To address the mechanism underlying the long-range allosteric activation of the catalytic K-Ras4B by an additional allosteric GTP-Ras through SOS, we employed molecular dynamics simulation of the K-Ras4BG13D•SOScat complex with and without an allosteric GTP-bound K-Ras4BG13D. We found that the binding of an allosteric GTP-K-Ras4BG13D enhanced the affinity between the catalytic K-Ras4BG13D and SOScat, forming a more stable conformational state. The peeling away of the switch I from the nucleotide binding site facilitated the dissociation of GDP, thereby contributing to the increased nucleotide exchange rate. The community networks further showed stronger edge connection upon allosteric GTP-K-Ras4BG13D binding, which represented an increased interaction between catalytic K-Ras4BG13D and SOScat. Moreover, GTP-K-Ras4BG13D binding transmitted allosteric signaling pathways though the Cdc25 domain of SOS that enhanced the allosteric regulatory from the K-Ras4BG13D allosteric site to the catalytic site. This study may provide an in-depth mechanism for abnormal activation and allosteric regulation of K-Ras4BG13D.
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Affiliation(s)
- Xuan He
- Department of Pharmacy, Ruijin Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai, China
| | - Kui Du
- School of Chemistry and Chemical Engineering, Shaoxing University, Shaoxing, China
| | - Yuanhao Wang
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - 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, China
| | - Mingyu Li
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Duan Ni
- The Charles Perkins Centre, University of Sydney, Sydney, NSW, Australia
| | - 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, China
- Medicinal Chemistry and Bioinformatics Center, Shanghai Jiao Tong University, School of Medicine, Shanghai, China
| | - Xiaolan Bian
- Department of Pharmacy, Ruijin Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai, China
| | - Yaqin Liu
- Medicinal Chemistry and Bioinformatics Center, Shanghai Jiao Tong University, School of Medicine, Shanghai, China
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13
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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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14
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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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15
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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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16
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Nussinov R, Jang H, Gursoy A, Keskin O, Gaponenko V. Inhibition of Nonfunctional Ras. Cell Chem Biol 2021; 28:121-133. [PMID: 33440168 PMCID: PMC7897307 DOI: 10.1016/j.chembiol.2020.12.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 10/28/2020] [Accepted: 12/21/2020] [Indexed: 02/07/2023]
Abstract
Intuitively, functional states should be targeted; not nonfunctional ones. So why could drugging the inactive K-Ras4BG12Cwork-but drugging the inactive kinase will likely not? The reason is the distinct oncogenic mechanisms. Kinase driver mutations work by stabilizing the active state and/or destabilizing the inactive state. Either way, oncogenic kinases are mostly in the active state. Ras driver mutations work by quelling its deactivation mechanisms, GTP hydrolysis, and nucleotide exchange. Covalent inhibitors that bind to the inactive GDP-bound K-Ras4BG12C conformation can thus work. By contrast, in kinases, allosteric inhibitors work by altering the active-site conformation to favor orthosteric drugs. From the translational standpoint this distinction is vital: it expedites effective pharmaceutical development and extends the drug classification based on the mechanism of action. Collectively, here we postulate that drug action relates to blocking the mechanism of activation, not to whether the protein is in the active or inactive state.
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Affiliation(s)
- Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA; Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel.
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA
| | - Attila Gursoy
- Department of Computer Engineering, Koc University, Istanbul 34450, Turkey
| | - Ozlem Keskin
- Department of Chemical and Biological Engineering, Koc University, Istanbul 34450, Turkey
| | - Vadim Gaponenko
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, IL 60607, USA.
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17
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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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18
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Fragment-derived modulators of an industrial β-glucosidase. Biochem J 2020; 477:4383-4395. [PMID: 33111951 PMCID: PMC7702302 DOI: 10.1042/bcj20200507] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 10/26/2020] [Accepted: 10/27/2020] [Indexed: 11/17/2022]
Abstract
A fragment screen of a library of 560 commercially available fragments using a kinetic assay identified a small molecule that increased the activity of the fungal glycoside hydrolase TrBgl2. An analogue by catalogue approach and detailed kinetic analysis identified improved compounds that behaved as nonessential activators with up to a 2-fold increase in maximum activation. The compounds did not activate the related bacterial glycoside hydrolase CcBglA demonstrating specificity. Interestingly, an analogue of the initial fragment inhibits both TrBgl2 and CcBglA, apparently through a mixed-model mechanism. Although it was not possible to determine crystal structures of activator binding to 55 kDa TrBgl2, solution NMR experiments demonstrated a specific binding site for the activator. A partial assignment of the NMR spectrum gave the identity of the amino acids at this site, allowing a model for TrBgl2 activation to be built. The activator binds at the entrance of the substrate-binding site, generating a productive conformation for the enzyme-substrate complex.
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19
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Liao TJ, Jang H, Fushman D, Nussinov R. SOS1 interacts with Grb2 through regions that induce closed nSH3 conformations. J Chem Phys 2020; 153:045106. [PMID: 32752665 PMCID: PMC7390601 DOI: 10.1063/5.0013926] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 07/12/2020] [Indexed: 12/18/2022] Open
Abstract
Grb2 is an adaptor protein connecting the epidermal growth factor receptor and the downstream Son of sevenless 1 (SOS1), a Ras-specific guanine nucleotide exchange factor (RasGEF), which exchanges GDP by GTP. Grb2 contains three SH domains: N-terminal SH3 (nSH3), SH2, and C-terminal SH3 (cSH3). The C-terminal proline-rich (PR) domain of SOS1 regulates nSH3 open/closed conformations. Earlier, several nSH3 binding motifs were identified in the PR domain. More recently, we characterized by nuclear magnetic resonance and replica exchange simulations possible cSH3 binding regions. Among them, we discovered a cSH3-specific binding region. However, how PR binding at these sites regulates the nSH3/cSH3 conformation has been unclear. Here, we explore the nSH3/cSH3 interaction with linked and truncated PR segments using molecular dynamics simulations. Our 248 μs simulations include 620 distinct trajectories, each 400 ns. We construct the effective free energy landscape to validate the nSH3/cSH3 binding sites. The nSH3/cSH3-SOS1 peptide complex models indicate that strong peptide binders attract the flexible nSH3 n-Src loop, inducing a closed conformation of nSH3; by contrast, the cSH3 conformation remains unchanged. Inhibitors that disrupt the Ras-SOS1 interaction have been designed; the conformational details uncovered here may assist in the design of polypeptides inhibiting Grb2-SOS1 interaction, thus SOS1 recruitment to the membrane where Ras resides.
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Affiliation(s)
| | - Hyunbum Jang
- Computational Structural Biology Section, Basic Science Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702, USA
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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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21
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Liao TJ, Jang H, Nussinov R, Fushman D. High-Affinity Interactions of the nSH3/cSH3 Domains of Grb2 with the C-Terminal Proline-Rich Domain of SOS1. J Am Chem Soc 2020; 142:3401-3411. [PMID: 31970984 PMCID: PMC8459210 DOI: 10.1021/jacs.9b10710] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Grb2 is an adaptor protein that recruits Ras-specific guanine nucleotide exchange factor, Son of Sevenless 1 (SOS1), to the plasma membrane. SOS1 exchanges GDP by GTP, activating Ras. Grb2 consists of an SH2 domain flanked by N- and C-terminal SH3 domains (nSH3/cSH3). Grb2 nSH3/cSH3 domains have strong binding affinity for the SOS1 proline-rich (PR) domain that mediates the Grb2-SOS1 interaction. The nSH3/cSH3 domains have distinct preferred binding motifs: PxxPxR for nSH3 and PxxxRxxKP for cSH3 (x represents any natural amino acid). Several nSH3-binding motifs have been identified in the SOS1 PR domain but none specific for cSH3 binding. Even though both nSH3 and cSH3 exhibit the strongest binding to the SOS1 peptide PVPPPVPPRRRP, this mutually exclusive binding combined with other potential nSH3/cSH3 binding regions in SOS1 makes understanding the Grb2-SOS1 interaction challenging. To identify the SOS1-cSH3 binding sites, we selected seven potential binding segments in SOS1. The synthesized peptides were tested for their binding to nSH3/cSH3. Our NMR data reveal that the PKLPPKTYKREH peptide has strong binding affinity for cSH3, but very weak for nSH3. The binding specificity suggests that the most likely Grb2-SOS1 binding mode is through nSH3-PVPPPVPPRRRP and cSH3-PKLPPKTYKREH interactions, which is supported by replica-exchange simulations for the Grb2-SOS1 complex models. We propose that nSH3/cSH3 binding peptides, which effectively interrupt Grb2-SOS1 association, can serve as tumor suppressors. The Grb2-SOS1 mechanism outlined here offers new venues for future therapeutic strategies for upstream mutations in cancer, such as in EGFR.
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Affiliation(s)
- Tsung-Jen Liao
- Biophysics Program, Institute for Physical Science and Technology , University of Maryland , College Park , Maryland 20742 , United States
- Computational Structural Biology Section, Basic Science Program , Frederick National Laboratory for Cancer Research , Frederick , Maryland 21702 , United States
| | - Hyunbum Jang
- Computational Structural Biology Section, Basic Science Program , Frederick National Laboratory for Cancer Research , Frederick , Maryland 21702 , United States
| | - Ruth Nussinov
- Computational Structural Biology Section, Basic Science Program , Frederick National Laboratory for Cancer Research , Frederick , Maryland 21702 , United States
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine , Tel Aviv University , Tel Aviv 69978 , Israel
| | - David Fushman
- Biophysics Program, Institute for Physical Science and Technology , University of Maryland , College Park , Maryland 20742 , United States
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Organization , University of Maryland , College Park , Maryland 20742 , United States
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22
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Nussinov R, Tsai CJ, Jang H. Does Ras Activate Raf and PI3K Allosterically? Front Oncol 2019; 9:1231. [PMID: 31799192 PMCID: PMC6874141 DOI: 10.3389/fonc.2019.01231] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 10/28/2019] [Indexed: 12/11/2022] Open
Abstract
The mechanism through which oncogenic Ras activates its effectors is vastly important to resolve. If allostery is at play, then targeting allosteric pathways could help in quelling activation of MAPK (Raf/MEK/ERK) and PI3K (PI3K/Akt/mTOR) cell proliferation pathways. On the face of it, allosteric activation is reasonable: Ras binding perturbs the conformational ensembles of its effectors. Here, however, we suggest that at least for Raf, PI3K, and NORE1A (RASSF5), that is unlikely. Raf's long disordered linker dampens effective allosteric activation. Instead, we suggest that the high-affinity Ras–Raf binding relieves Raf's autoinhibition, shifting Raf's ensemble from the inactive to the nanocluster-mediated dimerized active state, as Ras also does for NORE1A. PI3K is recruited and allosterically activated by RTK (e.g., EGFR) at the membrane. Ras restrains PI3K's distribution and active site orientation. It stabilizes and facilitates PIP2 binding at the active site and increases the PI3K residence time at the membrane. Thus, RTKs allosterically activate PI3Kα; however, merging their action with Ras accomplishes full activation. Here we review their activation mechanisms in this light and draw attention to implications for their 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, United States.,Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, 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, United States
| | - Hyunbum Jang
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, MD, United States
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23
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Dynamic Protein Allosteric Regulation and Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1163:25-43. [DOI: 10.1007/978-981-13-8719-7_2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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24
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Jang H, Banerjee A, Marcus K, Makowski L, Mattos C, Gaponenko V, Nussinov R. The Structural Basis of the Farnesylated and Methylated KRas4B Interaction with Calmodulin. Structure 2019; 27:1647-1659.e4. [PMID: 31495533 DOI: 10.1016/j.str.2019.08.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 07/31/2019] [Accepted: 08/16/2019] [Indexed: 02/07/2023]
Abstract
Ca2+-calmodulin (CaM) extracts KRas4B from the plasma membrane, suggesting that KRas4B/CaM interaction plays a role in regulating Ras signaling. To gain mechanistic insight, we provide a computational model, supported by experimental structural data, of farnesylated/methylated KRas4B1-185 interacting with CaM in solution and at anionic membranes including signaling lipids. Due to multiple interaction modes, we observe diverse conformational ensembles of the KRas4B-CaM complex. A highly populated conformation reveals the catalytic domain interacting with the N-lobe and the hypervariable region (HVR) wrapping around the linker with the farnesyl docking to the extended CaM's C-lobe pocket. Alternatively, KRas4B can interact with collapsed CaM with the farnesyl penetrating CaM's center. At anionic membranes, CaM interacts with the catalytic domain with large fluctuations, drawing the HVR. Signaling lipids establishing strong salt bridges with CaM prevent membrane departure. Membrane-interacting KRas4B-CaM complex can productively recruit phosphatidylinositol 3-kinase α (PI3Kα) to the plasma membrane, serving as a coagent in activating PI3Kα/Akt signaling.
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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
| | - Avik Banerjee
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Kendra Marcus
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA
| | - Lee Makowski
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA
| | - Carla Mattos
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA
| | - Vadim Gaponenko
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, IL 60607, 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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25
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Autoinhibition in Ras effectors Raf, PI3Kα, and RASSF5: a comprehensive review underscoring the challenges in pharmacological intervention. Biophys Rev 2018; 10:1263-1282. [PMID: 30269291 PMCID: PMC6233353 DOI: 10.1007/s12551-018-0461-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 09/17/2018] [Indexed: 02/06/2023] Open
Abstract
Autoinhibition is an effective mechanism that guards proteins against spurious activation. Despite its ubiquity, the distinct organizations of the autoinhibited states and their release mechanisms differ. Signaling is most responsive to the cell environment only if a small shift in the equilibrium is required to switch the system from an inactive (occluded) to an active (exposed) state. Ras signaling follows this paradigm. This underscores the challenge in pharmacological intervention to exploit and enhance autoinhibited states. Here, we review autoinhibition and release mechanisms at the membrane focusing on three representative Ras effectors, Raf protein kinase, PI3Kα lipid kinase, and NORE1A (RASSF5) tumor suppressor, and point to the ramifications to drug discovery. We further touch on Ras upstream and downstream signaling, Ras activation, and the Ras superfamily in this light, altogether providing a broad outlook of the principles and complexities of autoinhibition.
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