1
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Marasco M, Kirkpatrick J, Carlomagno T, Hub JS, Anselmi M. Phosphopeptide binding to the N-SH2 domain of tyrosine phosphatase SHP2 correlates with the unzipping of its central β-sheet. Comput Struct Biotechnol J 2024; 23:1169-1180. [PMID: 38510972 PMCID: PMC10951427 DOI: 10.1016/j.csbj.2024.02.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 02/26/2024] [Accepted: 02/26/2024] [Indexed: 03/22/2024] Open
Abstract
SHP2 is a tyrosine phosphatase that plays a regulatory role in multiple intracellular signaling cascades and is known to be oncogenic in certain contexts. In the absence of effectors, SHP2 adopts an autoinhibited conformation with its N-SH2 domain blocking the active site. Given the key role of N-SH2 in regulating SHP2, this domain has been extensively studied, often by X-ray crystallography. Using a combination of structural analyses and molecular dynamics (MD) simulations we show that the crystallographic environment can significantly influence the structure of the isolated N-SH2 domain, resulting in misleading interpretations. As an orthogonal method to X-ray crystallography, we use a combination of NMR spectroscopy and MD simulations to accurately determine the conformation of apo N-SH2 in solution. In contrast to earlier reports based on crystallographic data, our results indicate that apo N-SH2 in solution primarily adopts a conformation with a fully zipped central β-sheet, and that partial unzipping of this β-sheet is promoted by binding of either phosphopeptides or even phosphate/sulfate ions.
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Affiliation(s)
- Michelangelo Marasco
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - John Kirkpatrick
- School of Biosciences, University of Birmingham, Edgbaston, B15 2TT Birmingham, UK
| | - Teresa Carlomagno
- School of Biosciences, University of Birmingham, Edgbaston, B15 2TT Birmingham, UK
- Institute of Cancer and Genomic Sciences, University of Birmingham, Edgbaston, B15 2TT Birmingham, UK
| | - Jochen S. Hub
- Theoretical Physics and Center for Biophysics, Saarland University, 66123 Saarbrücken, Germany
| | - Massimiliano Anselmi
- Theoretical Physics and Center for Biophysics, Saarland University, 66123 Saarbrücken, Germany
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2
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Holguin-Cruz JA, Bui JM, Jha A, Na D, Gsponer J. Widespread alteration of protein autoinhibition in human cancers. Cell Syst 2024; 15:246-263.e7. [PMID: 38366601 DOI: 10.1016/j.cels.2024.01.009] [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: 01/31/2019] [Revised: 06/20/2023] [Accepted: 01/26/2024] [Indexed: 02/18/2024]
Abstract
Autoinhibition is a prevalent allosteric regulatory mechanism in signaling proteins. Reduced autoinhibition underlies the tumorigenic effect of some known cancer drivers, but whether autoinhibition is altered generally in cancer remains elusive. Here, we demonstrate that cancer-associated missense mutations, in-frame insertions/deletions, and fusion breakpoints are enriched within inhibitory allosteric switches (IASs) across all cancer types. Selection for IASs that are recurrently mutated in cancers identifies established and unknown cancer drivers. Recurrent missense mutations in IASs of these drivers are associated with distinct, cancer-specific changes in molecular signaling. For the specific case of PPP3CA, the catalytic subunit of calcineurin, we provide insights into the molecular mechanisms of altered autoinhibition by cancer mutations using biomolecular simulations, and demonstrate that such mutations are associated with transcriptome changes consistent with increased calcineurin signaling. Our integrative study shows that autoinhibition-modulating genetic alterations are positively selected for by cancer cells.
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Affiliation(s)
- Jorge A Holguin-Cruz
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Jennifer M Bui
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Ashwani Jha
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Dokyun Na
- School of Integrative Engineering, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul 156-756, Republic of Korea
| | - Jörg Gsponer
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada.
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3
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Kim SH, Bulos ML, Adams JA, Yun BK, Bishop AC. Single Ion Pair Is Essential for Stabilizing SHP2's Open Conformation. Biochemistry 2024; 63:273-281. [PMID: 38251939 DOI: 10.1021/acs.biochem.3c00609] [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: 01/23/2024]
Abstract
Src-homology-2-domain-containing PTP-2 (SHP2) is a widely expressed signaling enzyme whose misregulation is associated with multiple human pathologies. SHP2's enzymatic activity is controlled by a conformational equilibrium between its autoinhibited ("closed") state and its activated ("open") state. Although SHP2's closed state has been extensively characterized, the putative structure of its open form has only been revealed in the context of a highly activated mutant (E76K), and no systematic studies of the biochemical determinants of SHP2's open-state stabilization have been reported. To identify amino-acid interactions that are critical for stabilizing SHP2's active state, we carried out a mutagenic study of residues that lie at potentially important interdomain interfaces of the open conformation. The open/closed equilibria of the mutants were evaluated, and we identified several interactions that contribute to the stabilization of SHP2's open state. In particular, our findings establish that an ion pair between glutamate 249 on SHP2's PTP domain and arginine 111 on an interdomain loop is the key determinant of SHP2's open-state stabilization. Mutations that disrupt the R111/E249 ion pair substantially shift SHP2's open/closed equilibrium to the closed state, even compared to wild-type SHP2's basal-state equilibrium, which strongly favors the closed state. To the best of our knowledge, the ion-pair variants uncovered in this study are the first known SHP2 mutants in which autoinhibition is augmented with respect to the wild-type protein. Such "hyperinhibited" mutants may provide useful tools for signaling studies that investigate the connections between SHP2 inhibition and the suppression of human disease progression.
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Affiliation(s)
- Sean H Kim
- Department of Chemistry and Program in Biochemistry & Biophysics, Amherst College, Amherst, Massachusetts 01002, United States
| | - Maya L Bulos
- Department of Chemistry and Program in Biochemistry & Biophysics, Amherst College, Amherst, Massachusetts 01002, United States
| | - Jennifer A Adams
- Department of Chemistry and Program in Biochemistry & Biophysics, Amherst College, Amherst, Massachusetts 01002, United States
| | - B Koun Yun
- Department of Chemistry and Program in Biochemistry & Biophysics, Amherst College, Amherst, Massachusetts 01002, United States
| | - Anthony C Bishop
- Department of Chemistry and Program in Biochemistry & Biophysics, Amherst College, Amherst, Massachusetts 01002, United States
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4
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Anselmi M, Hub JS. Atomistic ensemble of active SHP2 phosphatase. Commun Biol 2023; 6:1289. [PMID: 38129686 PMCID: PMC10739809 DOI: 10.1038/s42003-023-05682-5] [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: 07/05/2023] [Accepted: 12/06/2023] [Indexed: 12/23/2023] Open
Abstract
SHP2 phosphatase plays an important role in regulating several intracellular signaling pathways. Pathogenic mutations of SHP2 cause developmental disorders and are linked to hematological malignancies and cancer. SHP2 comprises two tandemly-arranged SH2 domains, a catalytic PTP domain, and a disordered C-terminal tail. Under physiological, non-stimulating conditions, the catalytic site of PTP is occluded by the N-SH2 domain, so that the basal activity of SHP2 is low. Whereas the autoinhibited structure of SHP2 has been known for two decades, its active, open structure still represents a conundrum. Since the oncogenic mutant SHP2E76K almost completely populates the active, open state, this mutant has been extensively studied as a model for activated SHP2. By molecular dynamics simulations and accurate explicit-solvent SAXS curve predictions, we present the heterogeneous atomistic ensemble of constitutively active SHP2E76K in solution, encompassing a set of conformational arrangements and radii of gyration in agreement with experimental SAXS data.
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Affiliation(s)
- Massimiliano Anselmi
- Theoretical Physics and Center for Biophysics, Saarland University, 66123, Saarbrücken, Germany.
| | - Jochen S Hub
- Theoretical Physics and Center for Biophysics, Saarland University, 66123, Saarbrücken, Germany.
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5
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Liu Y, Zhang W, Jang H, Nussinov R. SHP2 clinical phenotype, cancer, or RASopathies, can be predicted by mutant conformational propensities. Cell Mol Life Sci 2023; 81:5. [PMID: 38085330 PMCID: PMC11072105 DOI: 10.1007/s00018-023-05052-8] [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: 07/12/2023] [Revised: 10/20/2023] [Accepted: 11/11/2023] [Indexed: 12/18/2023]
Abstract
SHP2 phosphatase promotes full activation of the RTK-dependent Ras/MAPK pathway. Its mutations can drive cancer and RASopathies, a group of neurodevelopmental disorders (NDDs). Here we ask how same residue mutations in SHP2 can lead to both cancer and NDD phenotypes, and whether we can predict what the outcome will be. We collected and analyzed mutation data from the literature and cancer databases and performed molecular dynamics simulations of SHP2 mutants. We show that both cancer and Noonan syndrome (NS, a RASopathy) mutations favor catalysis-prone conformations. As to cancer versus RASopathies, we demonstrate that cancer mutations are more likely to accelerate SHP2 activation than the NS mutations at the same genomic loci, in line with NMR data for K-Ras4B more aggressive mutations. The compiled experimental data and dynamic features of SHP2 mutants lead us to propose that different from strong oncogenic mutations, SHP2 activation by NS mutations is less likely to induce a transition of the ensemble from the SHP2 inactive state to the active state. Strong signaling promotes cell proliferation, a hallmark of cancer. Weak, or moderate signals are associated with differentiation. In embryonic neural cells, dysregulated differentiation is connected to NDDs. Our innovative work offers structural guidelines for identifying and correlating mutations with clinical outcomes, and an explanation for why bearers of RASopathy mutations may have a higher probability of cancer. Finally, we propose a drug strategy against SHP2 variants-promoting cancer and RASopathies.
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Affiliation(s)
- Yonglan Liu
- Cancer Innovation Laboratory, National Cancer Institute, Frederick, MD, 21702, USA
| | - Wengang Zhang
- Cancer Innovation Laboratory, National Cancer Institute, Frederick, MD, 21702, USA
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research, Frederick, MD, 21702, USA
| | - 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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6
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Marasco M, Kirkpatrick J, Carlomagno T, Hub JS, Anselmi M. Experiment-guided molecular simulations define a heterogeneous structural ensemble for the PTPN11 tandem SH2 domains. Chem Sci 2023; 14:5743-5755. [PMID: 37265738 PMCID: PMC10231330 DOI: 10.1039/d3sc00746d] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 05/04/2023] [Indexed: 06/03/2023] Open
Abstract
SHP2 plays an important role in regulating cellular processes, and its pathogenic mutations cause developmental disorders and are linked to cancer. SHP2 is a multidomain protein, comprising two SH2 domains arranged in tandem, a catalytic PTP domain, and a disordered C-terminal tail. SHP2 is activated upon binding two linked phosphopeptides to its SH2 domains, and the peptide orientation and spacing between binding sites are critical for enzymatic activation. For decades, the tandem SH2 has been extensively studied to identify the relative orientation of the two SH2 domains that most effectively binds effectors. So far, neither crystallography nor experiments in solution have provided conclusive results. Using experiment-guided molecular simulations, we determine the heterogeneous structural ensemble of the tandem SH2 in solution in agreement with experimental data from small-angle X-ray scattering and NMR residual dipolar couplings. In the solution ensemble, N-SH2 adopts different orientations and positions relative to C-SH2. We suggest that the intrinsic structural plasticity of the tandem SH2 allows SHP2 to respond to external stimuli and is essential for its functional activity.
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Affiliation(s)
- Michelangelo Marasco
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center New York NY USA
| | - John Kirkpatrick
- School of Biosciences, University of Birmingham Edgbaston B15 2TT Birmingham UK
| | - Teresa Carlomagno
- School of Biosciences, University of Birmingham Edgbaston B15 2TT Birmingham UK
- Institute of Cancer and Genomic Sciences, University of Birmingham Edgbaston B15 2TT Birmingham UK
| | - Jochen S Hub
- Theoretical Physics and Center for Biophysics, Saarland University 66123 Saarbrücken Germany
| | - Massimiliano Anselmi
- Theoretical Physics and Center for Biophysics, Saarland University 66123 Saarbrücken Germany
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7
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Hou Y, Lu X, Xu Z, Qu J, Huang J. How a single mutation alters the protein structure: a simulation investigation on protein tyrosine phosphatase SHP2. RSC Adv 2023; 13:4263-4274. [PMID: 36760301 PMCID: PMC9891203 DOI: 10.1039/d2ra07472a] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 01/23/2023] [Indexed: 02/04/2023] Open
Abstract
Protein tyrosine phosphatase SHP2 is a key regulator modulating several signaling pathways. The oncogenic mutation E76K in SHP2 releases the enzyme from an autoinhibited, closed conformation into an active, open conformation. Here, we investigated the conformational dynamics of SHP2 and the effect of the E76K mutation on its conformational ensemble via extensive molecular dynamics (MD) and metadynamics (MetaD) simulations. Our simulations provide atomistic details on how the E76K mutated SHP2 prefers the open state and also reveal that the transition between the closed and the open states is highly collective. Several intermediate metastable states during the conformational transition between the closed and the open states were also investigated. Understanding how the single E76K mutation induces the conformational change in SHP2 could facilitate the further design of SHP2 inhibitors.
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Affiliation(s)
- Yingnan Hou
- Westlake AI Therapeutics Lab, Westlake Laboratory of Life Sciences and Biomedicine 18 Shilongshan Road Hangzhou 310024 Zhejiang China .,Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University 18 Shilongshan Road Hangzhou 310024 Zhejiang China
| | - Xiaoli Lu
- Westlake AI Therapeutics Lab, Westlake Laboratory of Life Sciences and Biomedicine 18 Shilongshan Road Hangzhou 310024 Zhejiang China .,Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University 18 Shilongshan Road Hangzhou 310024 Zhejiang China
| | - Ziyao Xu
- BioMap2 Kexueyuan South RoadBeijing 100000China
| | - Jiarun Qu
- BioMap2 Kexueyuan South RoadBeijing 100000China
| | - Jing Huang
- Westlake AI Therapeutics Lab, Westlake Laboratory of Life Sciences and Biomedicine 18 Shilongshan Road Hangzhou 310024 Zhejiang China .,Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University 18 Shilongshan Road Hangzhou 310024 Zhejiang China
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8
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Hosoe Y, Miyanoiri Y, Re S, Ochi S, Asahina Y, Kawakami T, Kuroda M, Mizuguchi K, Oda M. Structural dynamics of the N‐terminal
SH2
domain of
PI3K
in its free and
CD28
‐bound states. FEBS J 2022; 290:2366-2378. [PMID: 36282120 DOI: 10.1111/febs.16666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 08/29/2022] [Accepted: 10/24/2022] [Indexed: 11/06/2022]
Abstract
Protein conformational changes with fluctuations are fundamental aspects of protein-protein interactions (PPIs); understanding these motions is required for the rational design of PPI-regulating compounds. Src homology 2 (SH2) domains are commonly found in adapter proteins involved in signal transduction and specifically bind to consensus motifs of proteins containing phosphorylated tyrosine (pY). Here, we analysed the interaction between the N-terminal SH2 domain (nSH2) of the regulatory subunit in phosphoinositide 3-kinase (PI3K) and the cytoplasmic region of the T-cell co-receptor, CD28, using NMR and molecular dynamics (MD) simulations. First, we assigned the backbone signals of nSH2 on 1 H-15 N heteronuclear single quantum coherence spectra in the absence or presence of the CD28 phosphopeptide, SDpYMNMTPRRPG. Chemical shift perturbation experiments revealed allosteric changes at the BC loop and the C-terminal region of nSH2 upon CD28 binding. NMR relaxation experiments showed a conformational exchange associated with CD28 binding in these regions. The conformational stabilisation of the C-terminal region correlated with the regulation of PI3K catalytic function. Further, using 19 F- and 31 P-labelled CD28 phosphopeptide, we analysed the structural dynamics of CD28 and demonstrated that the aromatic ring of the pY residue fluctuated between multiple conformations upon nSH2 binding. Our MD simulations largely explained the NMR results and the structural dynamics of nSH2 and CD28 in both bound and unbound states. Notably, in addition to its major conformation, we detected a minor conformation of nSH2 in the CD28 bound state that may explain the allosteric conformational change in the BC loop.
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Affiliation(s)
- Yuhi Hosoe
- Graduate School of Life and Environmental Sciences Kyoto Prefectural University Japan
| | | | - Suyong Re
- Artificial Intelligence Center for Health and Biomedical Research National Institutes of Biomedical Innovation, Health, and Nutrition Osaka Japan
| | - Saki Ochi
- Graduate School of Life and Environmental Sciences Kyoto Prefectural University Japan
| | - Yuya Asahina
- Institute for Protein Research Osaka University Japan
| | - Toru Kawakami
- Institute for Protein Research Osaka University Japan
| | - Masataka Kuroda
- Artificial Intelligence Center for Health and Biomedical Research National Institutes of Biomedical Innovation, Health, and Nutrition Osaka Japan
- Discovery Technology Laboratories Mitsubishi Tanabe Pharma Corporation Yokohama Japan
| | - Kenji Mizuguchi
- Institute for Protein Research Osaka University Japan
- Artificial Intelligence Center for Health and Biomedical Research National Institutes of Biomedical Innovation, Health, and Nutrition Osaka Japan
| | - Masayuki Oda
- Graduate School of Life and Environmental Sciences Kyoto Prefectural University Japan
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9
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Asmamaw MD, Shi XJ, Zhang LR, Liu HM. A comprehensive review of SHP2 and its role in cancer. Cell Oncol 2022; 45:729-753. [PMID: 36066752 DOI: 10.1007/s13402-022-00698-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/26/2022] [Indexed: 12/26/2022] Open
Abstract
Src homology 2-containing protein tyrosine phosphatase 2 (SHP2) is a non-receptor protein tyrosine phosphatase ubiquitously expressed mainly in the cytoplasm of several tissues. SHP2 modulates diverse cell signaling events that control metabolism, cell growth, differentiation, cell migration, transcription and oncogenic transformation. It interacts with diverse molecules in the cell, and regulates key signaling events including RAS/ERK, PI3K/AKT, JAK/STAT and PD-1 pathways downstream of several receptor tyrosine kinases (RTKs) upon stimulation by growth factors and cytokines. SHP2 acts as both a phosphatase and a scaffold, and plays prominently oncogenic functions but can be tumor suppressor in a context-dependent manner. It typically acts as a positive regulator of RTKs signaling with some inhibitory functions reported as well. SHP2 expression and activity is regulated by such factors as allosteric autoinhibition, microRNAs, ubiquitination and SUMOylation. Dysregulation of SHP2 expression or activity causes many developmental diseases, and hematological and solid tumors. Moreover, upregulated SHP2 expression or activity also decreases sensitivity of cancer cells to anticancer drugs. SHP2 is now considered as a compelling anticancer drug target and several classes of SHP2 inhibitors with different mode of action are developed with some already in clinical trial phases. Moreover, novel SHP2 substrates and functions are rapidly growing both in cell and cancer. In view of this, we comprehensively and thoroughly reviewed literatures about SHP2 regulatory mechanisms, substrates and binding partners, biological functions, roles in human cancers, and different classes of small molecule inhibitors target this oncoprotein in cancer.
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Affiliation(s)
- Moges Dessale Asmamaw
- Department of Pharmacology, School of Basic Medical Sciences, State Key Laboratory for Esophageal Cancer Prevention and Treatment, Zhengzhou University, Zhengzhou, Henan Province, 450001, People's Republic of China
| | - Xiao-Jing Shi
- Academy of Medical Sciences, Zhengzhou University, Zhengzhou, Henan Province, 450052, People's Republic of China
| | - Li-Rong Zhang
- Department of Pharmacology, School of Basic Medical Sciences, State Key Laboratory for Esophageal Cancer Prevention and Treatment, Zhengzhou University, Zhengzhou, Henan Province, 450001, People's Republic of China.
| | - Hong-Min Liu
- School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, 450001, Henan Province, China. .,Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education of China, Zhengzhou, Henan Province, 450001, People's Republic of China.
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10
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Calligari P, Santucci V, Stella L, Bocchinfuso G. Discriminating between competing models for the allosteric regulation of oncogenic phosphatase SHP2 by characterizing its active state. Comput Struct Biotechnol J 2021; 19:6125-6139. [PMID: 34900129 PMCID: PMC8632847 DOI: 10.1016/j.csbj.2021.10.041] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 10/31/2021] [Accepted: 10/31/2021] [Indexed: 11/07/2022] Open
Abstract
The Src-homology 2 domain containing phosphatase 2 (SHP2) plays a critical role in crucial signaling pathways and is involved in oncogenesis and in developmental disorders. Its structure includes two SH2 domains (N-SH2 and C-SH2), and a protein tyrosine phosphatase (PTP) domain. Under basal conditions, SHP2 is auto-inhibited, with the N-SH2 domain blocking the PTP active site. Activation involves a rearrangement of the domains that makes the catalytic site accessible, coupled to the association between the SH2 domains and cognate proteins containing phosphotyrosines. Several aspects of this transition are debated and competing mechanistic models have been proposed. A crystallographic structure of SHP2 in an active state has been reported (PDB code 6crf), but several lines of evidence suggests that it is not fully representative of the conformations populated in solution. To clarify the structural rearrangements involved in SHP2 activation, enhanced sampling simulations of the autoinhibited and active states have been performed, for wild type SHP2 and its pathogenic E76K variant. Our results demonstrate that the crystallographic conformation of the active state is unstable in solution, and multiple interdomain arrangements are populated, thus allowing association to bisphosphorylated sequences. Contrary to a recent proposal, activation is coupled to the conformational changes of the N-SH2 binding site, which is significantly more accessible in the active sate, rather than to the structure of the central β-sheet of the domain. In this coupling, a previously undescribed role for the N-SH2 BG loop emerged.
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Key Words
- BTLA, B and T lymphocyte attenuator
- CTLA-4, cytotoxic T lymphocyte-associated antigen 4
- FRET, Förster resonance energy transfer
- Inter-domain dynamics
- JMML, juvenile myelomonocytic leukemia
- MD, molecular dynamics
- NS, Noonan syndrome
- NSML, Noonan syndrome with multiple lentigines
- PD-1, programmed cell death protein 1
- PDB, protein data bank
- PMF, potential of mean force
- PTP, protein tyrosine phosphatase
- Protein flexibility
- REMD, replica exchange molecular dynamics
- RMSD, root mean square deviation
- RMSF, root mean square fluctuation
- RTK, receptor tyrosine kinase
- Replica exchange molecular dynamics simulations
- SASA, solvent accessible surface area
- SAXS, small angle X-ray scattering
- SH2, Src homology 2
- SHP2 regulatory mechanism
- SHP2, Src homology 2 domain-containing phosphatase 2
- SIRPalpha, signal regulatory protein alpha
- pY, phosphorylated tyrosine
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Affiliation(s)
- Paolo Calligari
- Dipartimento di Scienze e Tecnologie Chimiche, Università di Roma Tor Vergata, Rome, Italy
| | - Valerio Santucci
- Dipartimento di Scienze e Tecnologie Chimiche, Università di Roma Tor Vergata, Rome, Italy
| | - Lorenzo Stella
- Dipartimento di Scienze e Tecnologie Chimiche, Università di Roma Tor Vergata, Rome, Italy
| | - Gianfranco Bocchinfuso
- Dipartimento di Scienze e Tecnologie Chimiche, Università di Roma Tor Vergata, Rome, Italy
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