1
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Chikunova A, Manley MP, Heijjer CN, Drenth CS, Cramer-Blok AJ, Ahmad MUD, Perrakis A, Ubbink M. Conserved proline residues prevent dimerization and aggregation in the β-lactamase BlaC. Protein Sci 2024; 33:e4972. [PMID: 38533527 DOI: 10.1002/pro.4972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 03/07/2024] [Accepted: 03/11/2024] [Indexed: 03/28/2024]
Abstract
Evolution leads to conservation of amino acid residues in protein families. Conserved proline residues are usually considered to ensure the correct folding and to stabilize the three-dimensional structure. Surprisingly, proline residues that are highly conserved in class A β-lactamases were found to tolerate various substitutions without large losses in enzyme activity. We investigated the roles of three conserved prolines at positions 107, 226, and 258 in the β-lactamase BlaC from Mycobacterium tuberculosis and found that mutations can lead to dimerization of the enzyme and an overall less stable protein that is prone to aggregate over time. For the variant Pro107Thr, the crystal structure shows dimer formation resembling domain swapping. It is concluded that the proline substitutions loosen the structure, enhancing multimerization. Even though the enzyme does not lose its properties without the conserved proline residues, the prolines ensure the long-term structural integrity of the enzyme.
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Affiliation(s)
- A Chikunova
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
| | - M P Manley
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
| | - C N Heijjer
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
| | - C S Drenth
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
| | - A J Cramer-Blok
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
| | - M Ud Din Ahmad
- Division of Biochemistry, The Netherlands Cancer Institute, Amsterdam, The Netherlands
- Oncode Institute, Division of Biochemistry, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - A Perrakis
- Division of Biochemistry, The Netherlands Cancer Institute, Amsterdam, The Netherlands
- Oncode Institute, Division of Biochemistry, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - M Ubbink
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
- Department of Infectious Diseases, Imperial College, London, UK
- Zocdoc, New York City, New York, USA
- ZoBio BV, Leiden, The Netherlands
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2
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Wittayavimol N, Iwabuchi E, Pateetin P, Miki Y, Onodera Y, Sasano H, Boonyaratanakornkit V. Progesterone receptor-Grb2 interaction is associated with better outcomes in breast cancer. J Steroid Biochem Mol Biol 2024; 237:106441. [PMID: 38070754 DOI: 10.1016/j.jsbmb.2023.106441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 12/04/2023] [Accepted: 12/05/2023] [Indexed: 12/22/2023]
Abstract
In addition to mediating nuclear transcription, PR mediates extranuclear functions mainly through the PR polyproline domain (PPD) interaction with the SH3 domain of cytoplasmic signaling molecules. PR-PPD-SH3 interaction inhibits EGF-mediated signaling and decreases lung cancer cell proliferation. Grb2 is an essential adaptor molecule with an SH2 domain flanked by two SH3 domains. In this study, we examined whether PR, through interaction between PR-PPD and Grb2-SH3, can interact with Grb2 in cells and breast cancer tissues. Our previous study shows that interaction between PR-PPD and Grb2 could interfere with cytoplasmic signaling and lead to inhibition of EGF-mediated signaling. GST-pulldown analysis shows that PR-PPD specifically interacts with the SH3 domains of Grb2. Immunofluorescence staining shows colocalization of PR and Grb2 in both the nucleus and cytoplasm in BT-474 breast cancer cells. Using Bimolecular Fluorescence Complementation (BiFC) analysis, we show that PR and Grb2 interact in breast cancer cells through the Grb2-SH3 domain. Proximity Ligation Assay (PLA) analysis of 43 breast cancer specimens shows that PR-Grb2 interaction is associated with low histological stage and negatively correlates with lymph node invasion and metastasis in breast cancer. These results, together with our previous findings, suggest that PR-PPD interaction with Grb2 plays an essential role in PR-mediated growth factor signaling inhibition and could contribute significantly to better prognosis in PR- and Grb2-positive breast cancer. Our finding provides a basis for additional studies to explore a novel therapeutic strategy for cancer treatment.
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Affiliation(s)
- Nattamolphan Wittayavimol
- Department of Clinical Chemistry and Graduate Program in Clinical Biochemistry and Molecular Medicine, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok 10330, Thailand
| | - Erina Iwabuchi
- Department of Pathology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Prangwan Pateetin
- Department of Clinical Chemistry and Graduate Program in Clinical Biochemistry and Molecular Medicine, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok 10330, Thailand
| | - Yasuhiro Miki
- Department of Disaster Obstetrics and Gynecology, International Research Institute of Disaster Science (IRIDes), Tohoku University, Sendai, Japan
| | - Yoshiaki Onodera
- Department of Pathology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Hironobu Sasano
- Department of Pathology, Tohoku University Graduate School of Medicine, Sendai, Japan
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3
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Wang D, Liu G, Meng Y, Chen H, Ye Z, Jing J. The Configuration of GRB2 in Protein Interaction and Signal Transduction. Biomolecules 2024; 14:259. [PMID: 38540680 PMCID: PMC10968029 DOI: 10.3390/biom14030259] [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: 01/26/2024] [Revised: 02/15/2024] [Accepted: 02/17/2024] [Indexed: 07/02/2024] Open
Abstract
Growth-factor-receptor-binding protein 2 (GRB2) is a non-enzymatic adaptor protein that plays a pivotal role in precisely regulated signaling cascades from cell surface receptors to cellular responses, including signaling transduction and gene expression. GRB2 binds to numerous target molecules, thereby modulating a complex cell signaling network with diverse functions. The structural characteristics of GRB2 are essential for its functionality, as its multiple domains and interaction mechanisms underpin its role in cellular biology. The typical signaling pathway involving GRB2 is initiated by the ligand stimulation to its receptor tyrosine kinases (RTKs). The activation of RTKs leads to the recruitment of GRB2 through its SH2 domain to the phosphorylated tyrosine residues on the receptor. GRB2, in turn, binds to the Son of Sevenless (SOS) protein through its SH3 domain. This binding facilitates the activation of Ras, a small GTPase, which triggers a cascade of downstream signaling events, ultimately leading to cell proliferation, survival, and differentiation. Further research and exploration into the structure and function of GRB2 hold great potential for providing novel insights and strategies to enhance medical approaches for related diseases. In this review, we provide an outline of the proteins that engage with domains of GRB2, along with the function of different GRB2 domains in governing cellular signaling pathways. This furnishes essential points of current studies for the forthcoming advancement of therapeutic medications aimed at GRB2.
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Affiliation(s)
- Dingyi Wang
- College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou 310014, China
- Hangzhou Institute of Medicine, Chinese Academy of Sciences, Zhejiang Cancer Hospital, Hangzhou 310022, China
| | - Guoxia Liu
- Hangzhou Institute of Medicine, Chinese Academy of Sciences, Zhejiang Cancer Hospital, Hangzhou 310022, China
- School of Life Science, Tianjin University, Tianjin 200072, China
| | - Yuxin Meng
- College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou 310014, China
- Hangzhou Institute of Medicine, Chinese Academy of Sciences, Zhejiang Cancer Hospital, Hangzhou 310022, China
| | - Hongjie Chen
- College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou 310014, China
- Hangzhou Institute of Medicine, Chinese Academy of Sciences, Zhejiang Cancer Hospital, Hangzhou 310022, China
| | - Zu Ye
- Hangzhou Institute of Medicine, Chinese Academy of Sciences, Zhejiang Cancer Hospital, Hangzhou 310022, China
- Zhejiang Key Laboratory of Prevention, Diagnosis and Therapy of Upper Gastrointestinal Cancer, Hangzhou 310022, China
| | - Ji Jing
- Hangzhou Institute of Medicine, Chinese Academy of Sciences, Zhejiang Cancer Hospital, Hangzhou 310022, China
- Zhejiang Key Laboratory of Prevention, Diagnosis and Therapy of Upper Gastrointestinal Cancer, Hangzhou 310022, China
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4
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Kazemein Jasemi NS, Mehrabipour M, Magdalena Estirado E, Brunsveld L, Dvorsky R, Ahmadian MR. Functional Classification and Interaction Selectivity Landscape of the Human SH3 Domain Superfamily. Cells 2024; 13:195. [PMID: 38275820 PMCID: PMC10814857 DOI: 10.3390/cells13020195] [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: 12/12/2023] [Revised: 01/09/2024] [Accepted: 01/17/2024] [Indexed: 01/27/2024] Open
Abstract
SRC homology 3 (SH3) domains are critical interaction modules that orchestrate the assembly of protein complexes involved in diverse biological processes. They facilitate transient protein-protein interactions by selectively interacting with proline-rich motifs (PRMs). A database search revealed 298 SH3 domains in 221 human proteins. Multiple sequence alignment of human SH3 domains is useful for phylogenetic analysis and determination of their selectivity towards PRM-containing peptides (PRPs). However, a more precise functional classification of SH3 domains is achieved by constructing a phylogenetic tree only from PRM-binding residues and using existing SH3 domain-PRP structures and biochemical data to determine the specificity within each of the 10 families for particular PRPs. In addition, the C-terminal proline-rich domain of the RAS activator SOS1 covers 13 of the 14 recognized proline-rich consensus sequence motifs, encompassing differential PRP pattern selectivity among all SH3 families. To evaluate the binding capabilities and affinities, we conducted fluorescence dot blot and polarization experiments using 25 representative SH3 domains and various PRPs derived from SOS1. Our analysis has identified 45 interacting pairs, with binding affinities ranging from 0.2 to 125 micromolar, out of 300 tested and potential new SH3 domain-SOS1 interactions. Furthermore, it establishes a framework to bridge the gap between SH3 and PRP interactions and provides predictive insights into the potential interactions of SH3 domains with PRMs based on sequence specifications. This novel framework has the potential to enhance the understanding of protein networks mediated by SH3 domain-PRM interactions and be utilized as a general approach for other domain-peptide interactions.
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Affiliation(s)
- Neda S. Kazemein Jasemi
- Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany; (N.S.K.J.); (M.M.); (R.D.)
| | - Mehrnaz Mehrabipour
- Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany; (N.S.K.J.); (M.M.); (R.D.)
| | - Eva Magdalena Estirado
- Laboratory of Chemical Biology, Department of Biomedical Engineering and Institute for Complex Molecular Systems (ICMS), Eindhoven University of Technology, P.O. Box 513, 5600MB Eindhoven, The Netherlands; (E.M.E.); (L.B.)
| | - Luc Brunsveld
- Laboratory of Chemical Biology, Department of Biomedical Engineering and Institute for Complex Molecular Systems (ICMS), Eindhoven University of Technology, P.O. Box 513, 5600MB Eindhoven, The Netherlands; (E.M.E.); (L.B.)
| | - Radovan Dvorsky
- Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany; (N.S.K.J.); (M.M.); (R.D.)
| | - Mohammad R. Ahmadian
- Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany; (N.S.K.J.); (M.M.); (R.D.)
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5
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Dias RVR, Pedro RP, Sanches MN, Moreira GC, Leite VBP, Caruso IP, de Melo FA, de Oliveira LC. Unveiling Metastable Ensembles of GRB2 and the Relevance of Interdomain Communication during Folding. J Chem Inf Model 2023; 63:6344-6353. [PMID: 37824286 DOI: 10.1021/acs.jcim.3c00955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2023]
Abstract
The folding process of multidomain proteins is a highly intricate phenomenon involving the assembly of distinct domains into a functional three-dimensional structure. During this process, each domain may fold independently while interacting with others. The folding of multidomain proteins can be influenced by various factors, including their composition, the structure of each domain, or the presence of disordered regions, as well as the surrounding environment. Misfolding of multidomain proteins can lead to the formation of nonfunctional structures associated with a range of diseases, including cancers or neurodegenerative disorders. Understanding this process is an important step for many biophysical analyses such as stability, interaction, malfunctioning, and rational drug design. One such multidomain protein is growth factor receptor-bound protein 2 (GRB2), an adaptor protein that is essential in regulating cell survival. GRB2 consists of one central Src homology 2 (SH2) domain flanked by two Src homology 3 (SH3) domains. The SH2 domain interacts with phosphotyrosine regions in other proteins, while the SH3 domains recognize proline-rich regions on protein partners during cell signaling. Here, we combined computational and experimental techniques to investigate the folding process of GRB2. Through computational simulations, we sampled the conformational space and mapped the mechanisms involved by the free energy profiles, which may indicate possible intermediate states. From the molecular dynamics trajectories, we used the energy landscape visualization method (ELViM), which allowed us to visualize a three-dimensional (3D) representation of the overall energy surface. We identified two possible parallel folding routes that cannot be seen in a one-dimensional analysis, with one occurring more frequently during folding. Supporting these results, we used differential scanning calorimetry (DSC) and fluorescence spectroscopy techniques to confirm these intermediate states in vitro. Finally, we analyzed the deletion of domains to compare our model outputs to previously published results, supporting the presence of interdomain modulation. Overall, our study highlights the significance of interdomain communication within the GRB2 protein and its impact on the formation, stability, and structural plasticity of the protein, which are crucial for its interaction with other proteins in key signaling pathways.
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Affiliation(s)
- Raphael V R Dias
- Department of Physics, São Paulo State University (UNESP), Institute of Biosciences, Humanities, and Exact Sciences, São José do Rio Preto, SP 15054-000, Brazil
- Multiuser Center for Biomolecular Innovation (CMIB), São Paulo State University (UNESP), São José do Rio Preto, SP 15054-000, Brazil
| | - Renan P Pedro
- Department of Physics, São Paulo State University (UNESP), Institute of Biosciences, Humanities, and Exact Sciences, São José do Rio Preto, SP 15054-000, Brazil
- Multiuser Center for Biomolecular Innovation (CMIB), São Paulo State University (UNESP), São José do Rio Preto, SP 15054-000, Brazil
| | - Murilo N Sanches
- Department of Physics, São Paulo State University (UNESP), Institute of Biosciences, Humanities, and Exact Sciences, São José do Rio Preto, SP 15054-000, Brazil
| | - Giovana C Moreira
- Department of Physics, São Paulo State University (UNESP), Institute of Biosciences, Humanities, and Exact Sciences, São José do Rio Preto, SP 15054-000, Brazil
- Multiuser Center for Biomolecular Innovation (CMIB), São Paulo State University (UNESP), São José do Rio Preto, SP 15054-000, Brazil
| | - Vitor B P Leite
- Department of Physics, São Paulo State University (UNESP), Institute of Biosciences, Humanities, and Exact Sciences, São José do Rio Preto, SP 15054-000, Brazil
| | - Icaro P Caruso
- Department of Physics, São Paulo State University (UNESP), Institute of Biosciences, Humanities, and Exact Sciences, São José do Rio Preto, SP 15054-000, Brazil
- Multiuser Center for Biomolecular Innovation (CMIB), São Paulo State University (UNESP), São José do Rio Preto, SP 15054-000, Brazil
| | - Fernando A de Melo
- Department of Physics, São Paulo State University (UNESP), Institute of Biosciences, Humanities, and Exact Sciences, São José do Rio Preto, SP 15054-000, Brazil
- Multiuser Center for Biomolecular Innovation (CMIB), São Paulo State University (UNESP), São José do Rio Preto, SP 15054-000, Brazil
| | - Leandro C de Oliveira
- Department of Physics, São Paulo State University (UNESP), Institute of Biosciences, Humanities, and Exact Sciences, São José do Rio Preto, SP 15054-000, Brazil
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6
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Thole JF, Waudby CA, Pielak GJ. Disordered proteins mitigate the temperature dependence of site-specific binding free energies. J Biol Chem 2023; 299:102984. [PMID: 36739945 PMCID: PMC10027511 DOI: 10.1016/j.jbc.2023.102984] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 01/12/2023] [Accepted: 02/01/2023] [Indexed: 02/05/2023] Open
Abstract
Biophysical characterization of protein-protein interactions involving disordered proteins is challenging. A common simplification is to measure the thermodynamics and kinetics of disordered site binding using peptides containing only the minimum residues necessary. We should not assume, however, that these few residues tell the whole story. Son of sevenless, a multidomain signaling protein from Drosophila melanogaster, is critical to the mitogen-activated protein kinase pathway, passing an external signal to Ras, which leads to cellular responses. The disordered 55 kDa C-terminal domain of Son of sevenless is an autoinhibitor that blocks guanidine exchange factor activity. Activation requires another protein, Downstream of receptor kinase (Drk), which contains two Src homology 3 domains. Here, we utilized NMR spectroscopy and isothermal titration calorimetry to quantify the thermodynamics and kinetics of the N-terminal Src homology 3 domain binding to the strongest sites incorporated into the flanking disordered sequences. Comparing these results to those for isolated peptides provides information about how the larger domain affects binding. The affinities of sites on the disordered domain are like those of the peptides at low temperatures but less sensitive to temperature. Our results, combined with observations showing that intrinsically disordered proteins become more compact with increasing temperature, suggest a mechanism for this effect.
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Affiliation(s)
- Joseph F Thole
- Department of Chemistry, UNC-Chapel Hill, Chapel Hill, North Carolina, USA; Molecular and Cellular Biophysics Program, UNC-Chapel Hill, Chapel Hill, North Carolina, USA
| | | | - Gary J Pielak
- Department of Chemistry, UNC-Chapel Hill, Chapel Hill, North Carolina, USA; Molecular and Cellular Biophysics Program, UNC-Chapel Hill, Chapel Hill, North Carolina, USA; Department of Biochemistry & Biophysics, UNC-Chapel Hill, Chapel Hill, North Carolina, USA; Lineberger Cancer Center, UNC-Chapel Hill, Chapel Hill, North Carolina, USA; Integrative Program for Biological and Genome Sciences, UNC - Chapel Hill, Chapel Hill, North Carolina, USA.
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7
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A chemogenetic platform for controlling plasma membrane signaling and synthetic signal oscillation. Cell Chem Biol 2022; 29:1446-1464.e10. [PMID: 35835118 DOI: 10.1016/j.chembiol.2022.06.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 04/22/2022] [Accepted: 06/20/2022] [Indexed: 12/31/2022]
Abstract
Chemogenetic methods enabling the rapid translocation of specific proteins to the plasma membrane (PM) in a single protein-single ligand manner are useful tools in cell biology. We recently developed a technique, in which proteins fused to an Escherichia coli dihydrofolate reductase (eDHFR) variant carrying N-terminal hexalysine residues are recruited from the cytoplasm to the PM using the synthetic myristoyl-d-Cys-tethered trimethoprim (mDcTMP) ligand. However, this system achieved PM-specific translocation only when the eDHFR tag was fused to the N terminus of proteins, thereby limiting its application. In this report, we engineered a universal PM-targeting tag for mDcTMP-induced protein translocation by grafting the hexalysine motif into an intra-loop region of eDHFR. We demonstrate the broad applicability of the new loop-engineered eDHFR tag and mDcTMP pair for conditional PM recruitment and activation of various tag-fused signaling proteins with different fusion configurations and for reversibly and repeatedly controlling protein localization to generate synthetic signal oscillations.
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8
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Kazemein Jasemi NS, Reza Ahmadian M. Allosteric regulation of GRB2 modulates RAS activation. Small GTPases 2022; 13:282-286. [PMID: 35703160 DOI: 10.1080/21541248.2022.2089001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
RAS activation is a multiple-step process in which linkage of the extracellular stimuli to the RAS activator SOS1 is the main step in RAS activation. GRB2 adaptor protein is the main modulator in SOS1 recruitment to the plasma membrane and its activation. This interaction is well studied but the exact mechanism of GRB2-SOS1 complex formation and SOS1 activation has yet remained obscure. Here, a new allosteric mechanism for the GRB2 regulation is described as a prerequisite for the modulation of SOS1 activation. This regulatory mechanism comprises a series of intramolecular interactions which are potentiated by GRB2 interaction with upstream ligands.Abbreviations: GRB2, growth factor receptor-bound protein 2; SOS1, son of sevenless 1; RAS, Rat Sarcoma; GEF, guanine nucleotide exchange factor; GAP, GTPase-activating protein; HER2, human epidermal growth factor receptor; SH3, SRC Homology 3; SH2, SRC Homology 2; PRD, proline-rich domain; PRM, proline-rich motif; PRP, proline-rich peptide; RTK, receptor tyrosine kinases.
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Affiliation(s)
- Neda S Kazemein Jasemi
- Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Universitaetsstrasse 1, Building 22.03, 40255 Düsseldorf, Germany
| | - Mohammad Reza Ahmadian
- Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Universitaetsstrasse 1, Building 22.03, 40255 Düsseldorf, Germany
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9
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The intramolecular allostery of GRB2 governing its interaction with SOS1 is modulated by phosphotyrosine ligands. Biochem J 2021; 478:2793-2809. [PMID: 34232285 DOI: 10.1042/bcj20210105] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 07/01/2021] [Accepted: 07/07/2021] [Indexed: 02/04/2023]
Abstract
Growth factor receptor-bound protein 2 (GRB2) is a trivalent adaptor protein and a key element in signal transduction. It interacts via its flanking nSH3 and cSH3 domains with the proline-rich domain (PRD) of the RAS activator SOS1 and via its central SH2 domain with phosphorylated tyrosine residues of receptor tyrosine kinases (RTKs; e.g. HER2). The elucidation of structural organization and mechanistic insights into GRB2 interactions, however, remain challenging due to their inherent flexibility. This study represents an important advance in our mechanistic understanding of how GRB2 links RTKs to SOS1. Accordingly, it can be proposed that (1) HER2 pYP-bound SH2 potentiates GRB2 SH3 domain interactions with SOS1 (an allosteric mechanism); (2) the SH2 domain blocks cSH3, enabling nSH3 to bind SOS1 first before cSH3 follows (an avidity-based mechanism); and (3) the allosteric behavior of cSH3 to other domains appears to be unidirectional, although there is an allosteric effect between the SH2 and SH3 domains.
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10
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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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11
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Stadmiller SS, Aguilar JS, Waudby CA, Pielak GJ. Rapid Quantification of Protein-Ligand Binding via 19F NMR Lineshape Analysis. Biophys J 2020; 118:2537-2548. [PMID: 32348722 PMCID: PMC7231920 DOI: 10.1016/j.bpj.2020.03.031] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 03/19/2020] [Indexed: 12/14/2022] Open
Abstract
Fluorine incorporation is ideally suited to many NMR techniques, and incorporation of fluorine into proteins and fragment libraries for drug discovery has become increasingly common. Here, we use one-dimensional 19F NMR lineshape analysis to quantify the kinetics and equilibrium thermodynamics for the binding of a fluorine-labeled Src homology 3 (SH3) protein domain to four proline-rich peptides. SH3 domains are one of the largest and most well-characterized families of protein recognition domains and have a multitude of functions in eukaryotic cell signaling. First, we showe that fluorine incorporation into SH3 causes only minor structural changes to both the free and bound states using amide proton temperature coefficients. We then compare the results from lineshape analysis of one-dimensional 19F spectra to those from two-dimensional 1H-15N heteronuclear single quantum coherence spectra. Their agreement demonstrates that one-dimensional 19F lineshape analysis is a robust, low-cost, and fast alternative to traditional heteronuclear single quantum coherence-based experiments. The data show that binding is diffusion limited and indicate that the transition state is highly similar to the free state. We also measured binding as a function of temperature. At equilibrium, binding is enthalpically driven and arises from a highly positive activation enthalpy for association with small entropic contributions. Our results agree with those from studies using different techniques, providing additional evidence for the utility of 19F NMR lineshape analysis, and we anticipate that this analysis will be an effective tool for rapidly characterizing the energetics of protein interactions.
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Affiliation(s)
| | - Jhoan S Aguilar
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina
| | - Christopher A Waudby
- Department of Structural and Molecular Biology, University College London, London, United Kingdom
| | - Gary J Pielak
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina; Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina; Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina; Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, North Carolina.
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12
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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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Liao TJ, Jang H, Fushman D, Nussinov R. Allosteric KRas4B Can Modulate SOS1 Fast and Slow Ras Activation Cycles. Biophys J 2018; 115:629-641. [PMID: 30097175 PMCID: PMC6103739 DOI: 10.1016/j.bpj.2018.07.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 07/18/2018] [Accepted: 07/19/2018] [Indexed: 01/08/2023] Open
Abstract
Membrane-anchored Ras family proteins are activated by guanine nucleotide exchange factors such as SOS1. The CDC25 domain of SOS1 catalyzes GDP-to-GTP exchange, thereby activating Ras. Here, we aim to decipher the activation mechanism of KRas4B, a significantly mutated oncogene. We perform large-scale molecular dynamics simulations on 12 SOS1 systems, scrutinizing each step in two possible KRas4B activation cycles, fast and slow. To activate KRas4B at the CDC25 catalytic site, the allosteric site in the Ras exchanger motif (REM) domain of SOS1 needs to recruit a (nucleotide-bound) KRas4B molecule. Our simulations indicate that KRas4B-GTP interacts with the REM allosteric site more strongly than with the CDC25 catalytic site, consistent with its allosteric role in the GDP-to-GTP exchange. In the fast cycle, the allosteric KRas4B-GTP induces conformational change at the catalytic site. The conformational change facilitates loading KRas4B-GDP at the catalytic site and opening the KRas4B nucleotide-binding site for GDP release and GTP binding. GTP binding reduces the affinity of KRas4B-GTP to the CDC25 catalytic site, resulting in its release. By contrast, in the slow cycle, KRas4B-GDP binds at the allosteric REM site. The limited, altered conformational change that it induces prevents the exact alignments of switch I and II of KRas4B. The increasing binding strength at both binding sites due to interactions of regions other than switch I and II retards GDP release from the catalytic KRas4B, thus KRas4B activation. The accelerated activation cycle supports a positive feedback loop with allosteric signals communicating between the two Ras molecules and is the predominant, native function of SOS. SOS1 activation details may help drug discovery to inhibit Ras activation.
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Affiliation(s)
- Tsung-Jen Liao
- Cancer and Inflammation Program, Leidos Biomedical Research, Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, Maryland; Biophysics Program
| | - Hyunbum Jang
- Cancer and Inflammation Program, Leidos Biomedical Research, Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, Maryland
| | - David Fushman
- Biophysics Program; Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Organization, University of Maryland, College Park, Maryland
| | - Ruth Nussinov
- Cancer and Inflammation Program, Leidos Biomedical Research, Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, Maryland; Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
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Brown T, Brown N, Stollar EJ. Most yeast SH3 domains bind peptide targets with high intrinsic specificity. PLoS One 2018; 13:e0193128. [PMID: 29470497 PMCID: PMC5823434 DOI: 10.1371/journal.pone.0193128] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 02/04/2018] [Indexed: 01/07/2023] Open
Abstract
A need exists to develop bioinformatics for predicting differences in protein function, especially for members of a domain family who share a common fold, yet are found in a diverse array of proteins. Many domain families have been conserved over large evolutionary spans and representative genomic data during these periods are now available. This allows a simple method for grouping domain sequences to reveal common and unique/specific binding residues. As such, we hypothesize that sequence alignment analysis of the yeast SH3 domain family across ancestral species in the fungal kingdom can determine whether each member encodes specific information to bind unique peptide targets. With this approach, we identify important specific residues for a given domain as those that show little conservation within an alignment of yeast domain family members (paralogs) but are conserved in an alignment of its direct relatives (orthologs). We find most of the yeast SH3 domain family members have maintained unique amino acid conservation patterns that suggest they bind peptide targets with high intrinsic specificity through varying degrees of non-canonical recognition. For a minority of domains, we predict a less diverse binding surface, likely requiring additional factors to bind targets specifically. We observe that our predictions are consistent with high throughput binding data, which suggests our approach can probe intrinsic binding specificity in any other interaction domain family that is maintained during evolution.
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Affiliation(s)
- Tom Brown
- Math and Computer Science Department, Eastern New Mexico University, Portales, NM, United States of America
| | - Nick Brown
- Portales High School, Portales, NM, United States of America
| | - Elliott J. Stollar
- Physical Sciences Department, Eastern New Mexico University, Portales, NM, United States of America
- * E-mail:
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15
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Bhatt VS, Zeng D, Krieger I, Sacchettini JC, Cho JH. Binding Mechanism of the N-Terminal SH3 Domain of CrkII and Proline-Rich Motifs in cAbl. Biophys J 2017; 110:2630-2641. [PMID: 27332121 DOI: 10.1016/j.bpj.2016.05.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Revised: 04/29/2016] [Accepted: 05/04/2016] [Indexed: 12/14/2022] Open
Abstract
The N-terminal Src homology 3 (nSH3) domain of a signaling adaptor protein, CT-10 regulator of kinase II (CrkII), recognizes proline-rich motifs (PRMs) of binding partners, such as cAbl kinase. The interaction between CrkII and cAbl kinase is involved in the regulation of cell spreading, microbial pathogenesis, and cancer metastasis. Here, we report the detailed biophysical characterizations of the interactions between the nSH3 domain of CrkII and PRMs in cAbl. We identified that the nSH3 domain of CrkII binds to three PRMs in cAbl with virtually identical affinities. Structural studies, by using x-ray crystallography and NMR spectroscopy, revealed that the binding modes of all three nSH3:PRM complexes are highly similar to each other. Van 't Hoff analysis revealed that nSH3:PRM interaction is associated with favorable enthalpy and unfavorable entropy change. The combination of experimentally determined thermodynamic parameters, structure-based calculations, and (15)N NMR relaxation analysis highlights the energetic contribution of conformational entropy change upon the complex formation, and water molecules structured in the binding interface of the nSH3:PRM complex. Understanding the molecular basis of nSH3:PRM interaction will provide, to our knowledge, new insights for the rational design of small molecules targeting the interaction between CrkII and cAbl.
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Affiliation(s)
- Veer S Bhatt
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas
| | - Danyun Zeng
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas
| | - Inna Krieger
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas
| | - James C Sacchettini
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas
| | - Jae-Hyun Cho
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas.
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16
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Regions outside of conserved PxxPxR motifs drive the high affinity interaction of GRB2 with SH3 domain ligands. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:2560-9. [PMID: 26079855 DOI: 10.1016/j.bbamcr.2015.06.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 05/26/2015] [Accepted: 06/10/2015] [Indexed: 12/20/2022]
Abstract
SH3 domains are evolutionarily conserved protein interaction domains that control nearly all cellular processes in eukaryotes. The current model is that most SH3 domains bind discreet PxxPxR motifs with weak affinity and relatively low selectivity. However, the interactions of full-length SH3 domain-containing proteins with ligands are highly specific and have much stronger affinity. This suggests that regions outside of PxxPxR motifs drive these interactions. In this study, we observed that PxxPxR motifs were required for the binding of the adaptor protein GRB2 to short peptides from its ligand SOS1. Surprisingly, PxxPxR motifs from the proline rich region of SOS1 or CBL were neither necessary nor sufficient for the in vitro or in vivo interaction with full-length GRB2. Together, our findings show that regions outside of the consensus PxxPxR sites drive the high affinity association of GRB2 with SH3 domain ligands, suggesting that the binding mechanism for this and other SH3 domain interactions may be more complex than originally thought.
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Wuertenberger S, Groemping Y. A single PXXP motif in the C-terminal region of srGAP3 mediates binding to multiple SH3 domains. FEBS Lett 2015; 589:1156-63. [PMID: 25819436 DOI: 10.1016/j.febslet.2015.03.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Revised: 03/18/2015] [Accepted: 03/18/2015] [Indexed: 11/17/2022]
Abstract
The Slit-Robo GTPase-activating protein 3 (srGAP3) has been implicated in different critical aspects of neuronal development. These findings have mainly been based on the characterisation of the three conserved globular N-terminal domains, while the function of the C-terminal region (CTR) is still unknown. We show that this predicted unstructured region acts as an adaptor by binding to the endocytic proteins Amphiphysin, Endophilin-A2, Endophilin-A1, as well as the Ras signalling protein Grb2. All these interactions depend on a single proline-rich motif in the CTR and the Src-homology 3 domains of the binding partners. Via these interactions srGAP3 could link receptor signalling events to the endocytic machinery.
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Affiliation(s)
- Silvia Wuertenberger
- Max Planck Institute for Developmental Biology, Department of Protein Evolution, Spemannstr. 35, D-72076 Tübingen, Germany
| | - Yvonne Groemping
- Max Planck Institute for Developmental Biology, Department of Protein Evolution, Spemannstr. 35, D-72076 Tübingen, Germany.
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18
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The proline-rich region of 18.5 kDa myelin basic protein binds to the SH3-domain of Fyn tyrosine kinase with the aid of an upstream segment to form a dynamic complex in vitro. Biosci Rep 2014; 34:e00157. [PMID: 25343306 PMCID: PMC4266924 DOI: 10.1042/bsr20140149] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The intrinsically disordered 18.5 kDa classic isoform of MBP (myelin basic protein) interacts with Fyn kinase during oligodendrocyte development and myelination. It does so primarily via a central proline-rich SH3 (Src homology 3) ligand (T92–R104, murine 18.5 kDa MBP sequence numbering) that is part of a molecular switch due to its high degree of conservation and modification by MAP (mitogen-activated protein) and other kinases, especially at residues T92 and T95. Here, we show using co-transfection experiments of an early developmental oligodendroglial cell line (N19) that an MBP segment upstream of the primary ligand is involved in MBP–Fyn–SH3 association in cellula. Using solution NMR spectroscopy in vitro, we define this segment to comprise MBP residues (T62–L68), and demonstrate further that residues (V83–P93) are the predominant SH3-target, assessed by the degree of chemical shift change upon titration. We show by chemical shift index analysis that there is no formation of local poly-proline type II structure in the proline-rich segment upon binding, and by NOE (nuclear Overhauser effect) and relaxation measurements that MBP remains dynamic even while complexed with Fyn–SH3. The association is a new example first of a non-canonical SH3-domain interaction and second of a fuzzy MBP complex. MBP interacts with Fyn kinase during oligodendrocyte development and myelination. We show that there is no binding-induced PPII formation in the primary ligand segment, and that a region upstream is required for in vitro interaction.
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Rathod V, Jain S, Nandekar P, Sangamwar AT. Human pregnane X receptor: a novel target for anticancer drug development. Drug Discov Today 2014; 19:63-70. [DOI: 10.1016/j.drudis.2013.08.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 05/02/2013] [Accepted: 08/15/2013] [Indexed: 02/07/2023]
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20
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McDonald CB, El Hokayem J, Zafar N, Balke JE, Bhat V, Mikles DC, Deegan BJ, Seldeen KL, Farooq A. Allostery mediates ligand binding to Grb2 adaptor in a mutually exclusive manner. J Mol Recognit 2013; 26:92-103. [PMID: 23334917 DOI: 10.1002/jmr.2256] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Revised: 10/01/2012] [Accepted: 11/12/2012] [Indexed: 01/10/2023]
Abstract
Allostery plays a key role in dictating the stoichiometry and thermodynamics of multi-protein complexes driving a plethora of cellular processes central to health and disease. Herein, using various biophysical tools, we demonstrate that although Sos1 nucleotide exchange factor and Gab1 docking protein recognize two non-overlapping sites within the Grb2 adaptor, allostery promotes the formation of two distinct pools of Grb2-Sos1 and Grb2-Gab1 binary signaling complexes in concert in lieu of a composite Sos1-Grb2-Gab1 ternary complex. Of particular interest is the observation that the binding of Sos1 to the nSH3 domain within Grb2 sterically blocks the binding of Gab1 to the cSH3 domain and vice versa in a mutually exclusive manner. Importantly, the formation of both the Grb2-Sos1 and Grb2-Gab1 binary complexes is governed by a stoichiometry of 2:1, whereby the respective SH3 domains within Grb2 homodimer bind to Sos1 and Gab1 via multivalent interactions. Collectively, our study sheds new light on the role of allostery in mediating cellular signaling machinery.
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Affiliation(s)
- Caleb B McDonald
- Department of Biochemistry and Molecular Biology, Leonard Miller School of Medicine, University of Miami, Miami, FL 33136, USA
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21
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Peptide microarrays to probe for competition for binding sites in a protein interaction network. J Proteomics 2013; 89:71-80. [PMID: 23748025 DOI: 10.1016/j.jprot.2013.05.031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2012] [Revised: 05/06/2013] [Accepted: 05/20/2013] [Indexed: 11/20/2022]
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22
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de Mol NJ, Kruijtzer JA, Moret EE, Broutin I, Liskamp RM. Unusual binding of Grb2 protein to a bivalent polyproline-ligand immobilized on a SPR sensor: Intermolecular bivalent binding. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2013; 1834:524-35. [DOI: 10.1016/j.bbapap.2012.11.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Revised: 10/22/2012] [Accepted: 11/05/2012] [Indexed: 10/27/2022]
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Morgan AA, Rubenstein E. Proline: the distribution, frequency, positioning, and common functional roles of proline and polyproline sequences in the human proteome. PLoS One 2013; 8:e53785. [PMID: 23372670 PMCID: PMC3556072 DOI: 10.1371/journal.pone.0053785] [Citation(s) in RCA: 180] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Accepted: 12/05/2012] [Indexed: 11/19/2022] Open
Abstract
Proline is an anomalous amino acid. Its nitrogen atom is covalently locked within a ring, thus it is the only proteinogenic amino acid with a constrained phi angle. Sequences of three consecutive prolines can fold into polyproline helices, structures that join alpha helices and beta pleats as architectural motifs in protein configuration. Triproline helices are participants in protein-protein signaling interactions. Longer spans of repeat prolines also occur, containing as many as 27 consecutive proline residues. Little is known about the frequency, positioning, and functional significance of these proline sequences. Therefore we have undertaken a systematic bioinformatics study of proline residues in proteins. We analyzed the distribution and frequency of 687,434 proline residues among 18,666 human proteins, identifying single residues, dimers, trimers, and longer repeats. Proline accounts for 6.3% of the 10,882,808 protein amino acids. Of all proline residues, 4.4% are in trimers or longer spans. We detected patterns that influence function based on proline location, spacing, and concentration. We propose a classification based on proline-rich, polyproline-rich, and proline-poor status. Whereas singlet proline residues are often found in proteins that display recurring architectural patterns, trimers or longer proline sequences tend be associated with the absence of repetitive structural motifs. Spans of 6 or more are associated with DNA/RNA processing, actin, and developmental processes. We also suggest a role for proline in Kruppel-type zinc finger protein control of DNA expression, and in the nucleation and translocation of actin by the formin complex.
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Affiliation(s)
- Alexander A. Morgan
- Department of Biochemistry and Genome Technology Center, Stanford University Medical School, Stanford, California, United States of America
| | - Edward Rubenstein
- Department of Medicine, Stanford University School of Medicine, Stanford, California, United States of America
- * E-mail:
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24
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Abstract
Receptor tyrosine kinases (RTKs) exhibit basal tyrosine phosphorylation and activity in the absence of ligand stimulation, which has been attributed to the "leaky" nature of tyrosine kinase autoinhibition and stochastic collisions of receptors in the membrane bilayer. This basal phosphorylation does not produce a signal of sufficient amplitude and intensity to manifest in a biological response and hence is considered to be a passive, futile process that does not have any biological function. This paradigm has now been challenged by a study showing that the basal phosphorylation of RTKs is a physiologically relevant process that is actively inhibited by the intracellular adaptor protein growth factor receptor-bound 2 (Grb2) and serves to "prime" receptors for a rapid response to ligand stimulation. Grb2 is conventionally known for playing positive roles in RTK signaling. The discovery of a negative regulatory role for Grb2 reveals that this adaptor acts as a double-edged sword in the regulation of RTK signaling.
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Affiliation(s)
- Artur A Belov
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA
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25
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Interfacial water molecules in SH3 interactions: Getting the full picture on polyproline recognition by protein-protein interaction domains. FEBS Lett 2012; 586:2619-30. [DOI: 10.1016/j.febslet.2012.04.057] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Revised: 04/27/2012] [Accepted: 04/30/2012] [Indexed: 01/16/2023]
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26
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McDonald CB, Balke JE, Bhat V, Mikles DC, Deegan BJ, Seldeen KL, Farooq A. Multivalent binding and facilitated diffusion account for the formation of the Grb2-Sos1 signaling complex in a cooperative manner. Biochemistry 2012; 51:2122-35. [PMID: 22360309 DOI: 10.1021/bi3000534] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Despite its key role in driving cellular growth and proliferation through receptor tyrosine kinase (RTK) signaling, the Grb2-Sos1 macromolecular interaction remains poorly understood in mechanistic terms. Herein, using an array of biophysical methods, we provide evidence that although the Grb2 adaptor can potentially bind to all four PXψPXR motifs (designated herein S1-S4) located within the Sos1 guanine nucleotide exchange factor, the formation of the Grb2-Sos1 signaling complex occurs with a 2:1 stoichiometry. Strikingly, such bivalent binding appears to be driven by the association of the Grb2 homodimer to only two of four potential PXψPXR motifs within Sos1 at any one time. Of particular interest is the observation that of a possible six pairwise combinations in which S1-S4 motifs may act in concert for the docking of the Grb2 homodimer through bivalent binding, only S1 and S3, S1 and S4, S2 and S4, and S3 and S4 do so, while pairwise combinations of sites S1 and S2 and sites S2 and S3 appear to afford only monovalent binding. This salient observation implicates the role of local physical constraints in fine-tuning the conformational heterogeneity of the Grb2-Sos1 signaling complex. Importantly, the presence of multiple binding sites within Sos1 appears to provide a physical route for Grb2 to hop in a flip-flop manner from one site to the next through facilitated diffusion, and such rapid exchange forms the basis of positive cooperativity driving the bivalent binding of Grb2 to Sos1 with high affinity. Collectively, our study sheds new light on the assembly of a key macromolecular signaling complex central to cellular machinery in health and disease.
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Affiliation(s)
- Caleb B McDonald
- Department of Biochemistry and Molecular Biology and USylvester Braman Family Breast Cancer Institute, Leonard Miller School of Medicine, University of Miami, Miami, Florida 33136, United States
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Nag A, Monine M, Perelson AS, Goldstein B. Modeling and simulation of aggregation of membrane protein LAT with molecular variability in the number of binding sites for cytosolic Grb2-SOS1-Grb2. PLoS One 2012; 7:e28758. [PMID: 22396725 PMCID: PMC3291652 DOI: 10.1371/journal.pone.0028758] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Accepted: 11/14/2011] [Indexed: 01/08/2023] Open
Abstract
The linker for activation of T cells (LAT), the linker for activation of B cells (LAB), and the linker for activation of X cells (LAX) form a family of transmembrane adaptor proteins widely expressed in lymphocytes. These scaffolding proteins have multiple binding motifs that, when phosphorylated, bind the SH2 domain of the cytosolic adaptor Grb2. Thus, the valence of LAT, LAB and LAX for Grb2 is variable, depending on the strength of receptor activation that initiates phosphorylation. During signaling, the LAT population will exhibit a time-varying distribution of Grb2 valences from zero to three. In the cytosol, Grb2 forms 1∶1 and 2∶1 complexes with the guanine nucleotide exchange factor SOS1. The 2∶1 complex can bridge two LAT molecules when each Grb2, through their SH2 domains, binds to a phosphorylated site on a separate LAT. In T cells and mast cells, after receptor engagement, receptor phosphoyrlation is rapidly followed by LAT phosphorylation and aggregation. In mast cells, aggregates containing more than one hundred LAT molecules have been detected. Previously we considered a homogeneous population of trivalent LAT molecules and showed that for a range of Grb2, SOS1 and LAT concentrations, an equilibrium theory for LAT aggregation predicts the formation of a gel-like phase comprising a very large aggregate (superaggregate). We now extend this theory to investigate the effects of a distribution of Grb2 valence in the LAT population on the formation of LAT aggregates and superaggregate and use stochastic simulations to calculate the fraction of the total LAT population in the superaggregate.
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Affiliation(s)
- Ambarish Nag
- Theoretical Biololgy and Biophysics Group, Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America.
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Balakrishnan S, Scheuermann MJ, Zondlo NJ. Arginine mimetics using α-guanidino acids: introduction of functional groups and stereochemistry adjacent to recognition guanidiniums in peptides. Chembiochem 2012; 13:259-70. [PMID: 22213184 PMCID: PMC3712784 DOI: 10.1002/cbic.201100638] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Indexed: 01/19/2023]
Abstract
Arginine residues are broadly employed for specific biomolecular recognition, including in protein-protein, protein-DNA, and protein-RNA interactions. Arginine recognition commonly exploits the potential for bidentate electrostatic and hydrogen-bonding interactions. However, in arginine residues, the guanidinium functional group is located at the terminus of a flexible hydrocarbon side chain, which lacks the functionality to contribute to specific arginine-mediated recognition and may entropically disfavor binding. In order to enhance the potential for specificity and affinity in arginine-mediated molecular recognition, we have developed an approach to the synthesis of peptides that incorporates an α-guanidino acid as a novel arginine mimetic. α-Guanidino acids, derived from α-amino acids, with guanidinylation of the amino group, were incorporated stereospecifically into peptides on solid phase via coupling of an Fmoc amino acid to diaminopropionic acid (Dap), Fmoc deprotection, guanidinylation of the amine on solid phase, and deprotection, generating a peptide containing an α-functionalized arginine mimetic. This approach was examined by incorporating arginine mimetics into ligands for the Src, Grb, and Crk SH3 domains at the site of the key recognition arginine. Protein binding was examined for peptides containing guanidino acids derived from Gly, L-Val, L-Phe, L-Trp, D-Val, D-Phe, and D-Trp. We demonstrate that paralogue specificity and target site affinity may be modulated with the use of α-guanidino acid-derived arginine mimetics, generating peptides that exhibit enhanced Src specificity by selection against Grb and peptides that reverse the specificity of the native peptide ligand, with enhancements in Src target specificity of up to 15-fold (1.6 kcal mol(-1)).
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Affiliation(s)
- Shalini Balakrishnan
- Department of Chemistry and Biochemistry University of Delaware Newark, Delaware 19716 (USA)
| | - Michael J. Scheuermann
- Department of Chemistry and Biochemistry University of Delaware Newark, Delaware 19716 (USA)
| | - Neal J. Zondlo
- Department of Chemistry and Biochemistry University of Delaware Newark, Delaware 19716 (USA)
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29
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Smith GS, De Avila M, Paez PM, Spreuer V, Wills MK, Jones N, Boggs JM, Harauz G. Proline substitutions and threonine pseudophosphorylation of the SH3 ligand of 18.5-kDa myelin basic protein decrease its affinity for the Fyn-SH3 domain and alter process development and protein localization in oligodendrocytes. J Neurosci Res 2012; 90:28-47. [PMID: 21887699 PMCID: PMC3527418 DOI: 10.1002/jnr.22733] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Revised: 06/02/2011] [Accepted: 06/06/2011] [Indexed: 12/28/2022]
Abstract
The developmentally regulated myelin basic proteins (MBPs), which arise from the golli (gene of oligodendrocyte lineage) complex, are highly positively charged, intrinsically disordered, multifunctional proteins having several alternatively spliced isoforms and posttranslational modifications, and they play key roles in myelin compaction. The classic 18.5-kDa MBP isoform has a proline-rich region comprising amino acids 92-99 (murine sequence -T(92)PRTPPPS(99)-) that contains a minimal SH3 ligand domain. We have previously shown that 18.5-kDa MBP binds to several SH3 domains, including that of Fyn, a member of the Src family of tyrosine kinases involved in a number of signaling pathways during CNS development. To determine the physiological role of this binding as well as the role of phosphorylation of Thr92 and Thr95, in the current study we have produced several MBP variants specifically targeting phosphorylation sites and key structural regions of MBP's SH3 ligand domain. Using isothermal titration calorimetry, we have demonstrated that, compared with the wild-type protein, these variants have lower affinity for the SH3 domain of Fyn. Moreover, overexpression of N-terminal-tagged GFP versions in immortalized oligodendroglial N19 and N20.1 cell cultures results in aberrant elongation of membrane processes and increased branching complexity and inhibits the ability of MBP to decrease Ca(2+) influx. Phosphorylation of Thr92 can also cause MBP to traffic to the nucleus, where it may participate in additional protein-protein interactions. Coexpression of MBP with a constitutively active form of Fyn kinase resulted in membrane process elaboration, a phenomenon that was abolished by point amino acid substitutions in MBP's SH3 ligand domain. These results suggest that MBP's SH3 ligand domain plays a key role in intracellular protein interactions in vivo and may be required for proper membrane elaboration of developing oligodendrocytes and, further, that phosphorylation of Thr92 and Thr95 can regulate this function.
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Affiliation(s)
- Graham S.T. Smith
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Miguel De Avila
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Pablo M. Paez
- Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California
| | - Vilma Spreuer
- Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California
| | - Melanie K.B. Wills
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Nina Jones
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Joan M. Boggs
- Molecular Structure and Function, Hospital for Sick Children, and Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - George Harauz
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
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30
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Sethi A, Goldstein B, Gnanakaran S. Quantifying intramolecular binding in multivalent interactions: a structure-based synergistic study on Grb2-Sos1 complex. PLoS Comput Biol 2011; 7:e1002192. [PMID: 22022247 PMCID: PMC3192808 DOI: 10.1371/journal.pcbi.1002192] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Accepted: 07/27/2011] [Indexed: 01/27/2023] Open
Abstract
Numerous signaling proteins use multivalent binding to increase the specificity and affinity of their interactions within the cell. Enhancement arises because the effective binding constant for multivalent binding is larger than the binding constants for each individual interaction. We seek to gain both qualitative and quantitative understanding of the multivalent interactions of an adaptor protein, growth factor receptor bound protein-2 (Grb2), containing two SH3 domains interacting with the nucleotide exchange factor son-of-sevenless 1 (Sos1) containing multiple polyproline motifs separated by flexible unstructured regions. Grb2 mediates the recruitment of Sos1 from the cytosol to the plasma membrane where it activates Ras by inducing the exchange of GDP for GTP. First, using a combination of evolutionary information and binding energy calculations, we predict an additional polyproline motif in Sos1 that binds to the SH3 domains of Grb2. This gives rise to a total of five polyproline motifs in Sos1 that are capable of binding to the two SH3 domains of Grb2. Then, using a hybrid method combining molecular dynamics simulations and polymer models, we estimate the enhancement in local concentration of a polyproline motif on Sos1 near an unbound SH3 domain of Grb2 when its other SH3 domain is bound to a different polyproline motif on Sos1. We show that the local concentration of the Sos1 motifs that a Grb2 SH3 domain experiences is approximately 1000 times greater than the cellular concentration of Sos1. Finally, we calculate the intramolecular equilibrium constants for the crosslinking of Grb2 on Sos1 and use thermodynamic modeling to calculate the stoichiometry. With these equilibrium constants, we are able to predict the distribution of complexes that form at physiological concentrations. We believe this is the first systematic analysis that combines sequence, structure, and thermodynamic analyses to determine the stoichiometry of the complexes that are dominant in the cellular environment.
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Affiliation(s)
- Anurag Sethi
- Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
- Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
| | - Byron Goldstein
- Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
| | - S. Gnanakaran
- Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
- * E-mail:
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31
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Liu F, Giubellino A, Simister PC, Qian W, Giano MC, Feller SM, Bottaro DP, Burke TR. Application of ring-closing metathesis to Grb2 SH3 domain-binding peptides. Biopolymers 2011; 96:780-8. [PMID: 21830199 PMCID: PMC3402909 DOI: 10.1002/bip.21692] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Molecular processes depending on protein–protein interactions can use consensus recognition sequences that possess defined secondary structures. Left-handed polyproline II (PPII) helices are a class of secondary structure commonly involved with cellular signal transduction. However, unlike -helices, for which a substantial body of work exists regarding applications of ring-closing metathesis (RCM), there are few reports on the stabilization of PPII helices by RCM methodologies. The current study examined the effects of RCM macrocyclization on left-handed PPII helices involved with the SH3 domain-mediated binding of Sos1–Grb2. Starting with the Sos1-derived peptide “Ac-V1-P2-P3-P4-V5-P6-P7-R8-R9-R10-amide,” RCM macrocyclizations were conducted using alkenyl chains of varying lengths originating from the pyrrolidine rings of the Pro4 and Pro7 residues. The resulting macrocyclic peptides showed increased helicity as indicated by circular dichroism and enhanced abilities to block Grb2–Sos1 interactions in cell lysate pull-down assays. The synthetic approach may be useful in RCM macrocyclizations, where maintenance of proline integrity at both ring junctures is desired.
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Affiliation(s)
- Fa Liu
- Chemical Biology Laboratory, Molecular Discovery Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, NCI-Frederick, Frederick, MD 21702
| | - Alessio Giubellino
- Urologic Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20989
| | - Philip C. Simister
- Cell Signalling Group, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
| | - Wenjian Qian
- Chemical Biology Laboratory, Molecular Discovery Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, NCI-Frederick, Frederick, MD 21702
| | - Michael C. Giano
- Chemical Biology Laboratory, Molecular Discovery Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, NCI-Frederick, Frederick, MD 21702
| | - Stephan M. Feller
- Cell Signalling Group, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
| | - Donald P. Bottaro
- Urologic Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20989
| | - Terrence R. Burke
- Chemical Biology Laboratory, Molecular Discovery Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, NCI-Frederick, Frederick, MD 21702
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32
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Ladbury JE, Arold ST. Energetics of Src homology domain interactions in receptor tyrosine kinase-mediated signaling. Methods Enzymol 2011; 488:147-83. [PMID: 21195228 DOI: 10.1016/b978-0-12-381268-1.00007-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Intracellular signaling from receptor tyrosine kinases (RTK) on extracellular stimulation is fundamental to all cellular processes. The protein-protein interactions which form the basis of this signaling are mediated through a limited number of polypeptide domains. For signal transduction without corruption, based on a model where signaling pathways are considered as linear bimolecular relays, these interactions have to be highly specific. This is particularly the case when one considers that any cell may have copies of similar binding domains found in numerous proteins. In this work, an overview of the thermodynamics of binding of two of the most common of these domains (SH2 and SH3 domains) is given. This, coupled with insight from high-resolution structural detail, provides a comprehensive survey of how recognition of cognate binding sites for these domains occurs. Based on the data presented, we conclude that specificity offered by these interactions of SH2 and SH3 domains is limited and not sufficient to enforce mutual exclusivity in RTK-mediated signaling. This may explain the current lack of success in pharmaceutical intervention to inhibit the interactions of these domains when they are responsible for aberrant signaling and the resulting disease states such as cancer.
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Affiliation(s)
- John E Ladbury
- Department of Biochemistry and Molecular Biology, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
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33
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Falconer RJ, Collins BM. Survey of the year 2009: applications of isothermal titration calorimetry. J Mol Recognit 2010; 24:1-16. [DOI: 10.1002/jmr.1073] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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34
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McDonald CB, Seldeen KL, Deegan BJ, Bhat V, Farooq A. Binding of the cSH3 domain of Grb2 adaptor to two distinct RXXK motifs within Gab1 docker employs differential mechanisms. J Mol Recognit 2010; 24:585-96. [PMID: 21472810 DOI: 10.1002/jmr.1080] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2010] [Revised: 07/26/2010] [Accepted: 07/26/2010] [Indexed: 12/29/2022]
Abstract
A ubiquitous component of cellular signaling machinery, Gab1 docker plays a pivotal role in routing extracellular information in the form of growth factors and cytokines to downstream targets such as transcription factors within the nucleus. Here, using isothermal titration calorimetry (ITC) in combination with macromolecular modeling (MM), we show that although Gab1 contains four distinct RXXK motifs, designated G1, G2, G3, and G4, only G1 and G2 motifs bind to the cSH3 domain of Grb2 adaptor and do so with distinct mechanisms. Thus, while the G1 motif strictly requires the PPRPPKP consensus sequence for high-affinity binding to the cSH3 domain, the G2 motif displays preference for the PXVXRXLKPXR consensus. Such sequential differences in the binding of G1 and G2 motifs arise from their ability to adopt distinct polyproline type II (PPII)- and 3(10) -helical conformations upon binding to the cSH3 domain, respectively. Collectively, our study provides detailed biophysical insights into a key protein-protein interaction involved in a diverse array of signaling cascades central to health and disease.
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Affiliation(s)
- Caleb B McDonald
- Department of Biochemistry & Molecular Biology, USylvester Braman Family Breast Cancer Institute, Leonard Miller School of Medicine, University of Miami, Miami, FL 33136, USA
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35
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Pan Y, Tsai CJ, Ma B, Nussinov R. Mechanisms of transcription factor selectivity. Trends Genet 2010; 26:75-83. [PMID: 20074831 PMCID: PMC7316385 DOI: 10.1016/j.tig.2009.12.003] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2009] [Revised: 12/08/2009] [Accepted: 12/10/2009] [Indexed: 10/20/2022]
Abstract
The initiation of transcription is regulated by transcription factors (TFs) binding to DNA response elements (REs). How do TFs recognize specific binding sites among the many similar ones available in the genome? Recent research has illustrated that even a single nucleotide substitution can alter the selective binding of TFs to coregulators, that prior binding events can lead to selective DNA binding, and that selectivity is influenced by the availability of binding sites in the genome. Here, we combine structural insights with recent genomics screens to address the problem of TF-DNA interaction specificity. The emerging picture of selective binding site sequence recognition and TF activation involves three major factors: the cellular network, protein and DNA as dynamic conformational ensembles and the tight packing of multiple TFs and coregulators on stretches of regulatory DNA. The classification of TF recognition mechanisms based on these factors impacts our understanding of how transcription initiation is regulated.
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Affiliation(s)
- Yongping Pan
- Basic Science Program, SAIC-Frederick, Inc., Center for Cancer Research Nanobiology Program, NCI-Frederick, Frederick, MD 21702, USA
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36
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McDonald CB, Seldeen KL, Deegan BJ, Bhat V, Farooq A. Assembly of the Sos1-Grb2-Gab1 ternary signaling complex is under allosteric control. Arch Biochem Biophys 2009; 494:216-25. [PMID: 20005866 DOI: 10.1016/j.abb.2009.12.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2009] [Revised: 12/07/2009] [Accepted: 12/08/2009] [Indexed: 11/28/2022]
Abstract
Allostery has evolved as a form of local communication between interacting protein partners allowing them to quickly sense changes in their immediate vicinity in response to external cues. Herein, using isothermal titration calorimetry (ITC) in conjunction with circular dichroism (CD) and macromolecular modeling (MM), we show that the binding of Grb2 adaptor--a key signaling molecule involved in the activation of Ras GTPase--to its downstream partners Sos1 guanine nucleotide exchange factor and Gab1 docker is under tight allosteric regulation. Specifically, our findings reveal that the binding of one molecule of Sos1 to the nSH3 domain allosterically induces a conformational change within Grb2 such that the loading of a second molecule of Sos1 onto the cSH3 domain is blocked and, in so doing, allows Gab1 access to the cSH3 domain in an exclusively non-competitive manner to generate the Sos1-Grb2-Gab1 ternary signaling complex.
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Affiliation(s)
- Caleb B McDonald
- Department of Biochemistry & Molecular Biology and USylvester Braman Family Breast Cancer Institute, Leonard Miller School of Medicine, University of Miami, Miami, FL 33136, USA
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