1
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Vish KJ, Stiegler AL, Boggon TJ. Diverse p120RasGAP interactions with doubly phosphorylated partners EphB4, p190RhoGAP, and Dok1. J Biol Chem 2023; 299:105098. [PMID: 37507023 PMCID: PMC10470053 DOI: 10.1016/j.jbc.2023.105098] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 07/06/2023] [Accepted: 07/24/2023] [Indexed: 07/30/2023] Open
Abstract
RasGAP (p120RasGAP), the founding member of the GTPase-activating protein (GAP) family, is one of only nine human proteins to contain two SH2 domains and is essential for proper vascular development. Despite its importance, its interactions with key binding partners remains unclear. In this study we provide a detailed viewpoint of RasGAP recruitment to various binding partners and assess their impact on RasGAP activity. We reveal the RasGAP SH2 domains generate distinct binding interactions with three well-known doubly phosphorylated binding partners: p190RhoGAP, Dok1, and EphB4. Affinity measurements demonstrate a 100-fold weakened affinity for RasGAP-EphB4 binding compared to RasGAP-p190RhoGAP or RasGAP-Dok1 binding, possibly driven by single versus dual SH2 domain engagement with a dominant N-terminal SH2 interaction. Small-angle X-ray scattering reveals conformational differences between RasGAP-EphB4 binding and RasGAP-p190RhoGAP binding. Importantly, these interactions do not impact catalytic activity, implying RasGAP utilizes its SH2 domains to achieve diverse spatial-temporal regulation of Ras signaling in a previously unrecognized fashion.
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Affiliation(s)
- Kimberly J Vish
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | - Amy L Stiegler
- Department of Pharmacology, Yale University, New Haven, Connecticut, USA
| | - Titus J Boggon
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA; Department of Pharmacology, Yale University, New Haven, Connecticut, USA; Department of Yale Cancer Center, Yale University, New Haven, Connecticut, USA.
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2
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Timberlake AT, McGee S, Allington G, Kiziltug E, Wolfe EM, Stiegler AL, Boggon TJ, Sanyoura M, Morrow M, Wenger TL, Fernandes EM, Caluseriu O, Persing JA, Jin SC, Lifton RP, Kahle KT, Kruszka P. De novo variants implicate chromatin modification, transcriptional regulation, and retinoic acid signaling in syndromic craniosynostosis. Am J Hum Genet 2023; 110:846-862. [PMID: 37086723 PMCID: PMC10183468 DOI: 10.1016/j.ajhg.2023.03.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 03/24/2023] [Indexed: 04/24/2023] Open
Abstract
Craniosynostosis (CS) is the most common congenital cranial anomaly. Several Mendelian forms of syndromic CS are well described, but a genetic etiology remains elusive in a substantial fraction of probands. Analysis of exome sequence data from 526 proband-parent trios with syndromic CS identified a marked excess (observed 98, expected 33, p = 4.83 × 10-20) of damaging de novo variants (DNVs) in genes highly intolerant to loss-of-function variation (probability of LoF intolerance > 0.9). 30 probands harbored damaging DNVs in 21 genes that were not previously implicated in CS but are involved in chromatin modification and remodeling (4.7-fold enrichment, p = 1.1 × 10-11). 17 genes had multiple damaging DNVs, and 13 genes (CDK13, NFIX, ADNP, KMT5B, SON, ARID1B, CASK, CHD7, MED13L, PSMD12, POLR2A, CHD3, and SETBP1) surpassed thresholds for genome-wide significance. A recurrent gain-of-function DNV in the retinoic acid receptor alpha (RARA; c.865G>A [p.Gly289Arg]) was identified in two probands with similar CS phenotypes. CS risk genes overlap with those identified for autism and other neurodevelopmental disorders, are highly expressed in cranial neural crest cells, and converge in networks that regulate chromatin modification, gene transcription, and osteoblast differentiation. Our results identify several CS loci and have major implications for genetic testing and counseling.
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Affiliation(s)
- Andrew T Timberlake
- Hansjörg Wyss Department of Plastic Surgery, NYU Langone Medical Center, New York, NY, USA
| | | | - Garrett Allington
- Department of Pathology, Yale University School of Medicine, New Haven, CT, USA
| | - Emre Kiziltug
- Department of Pathology, Yale University School of Medicine, New Haven, CT, USA
| | - Erin M Wolfe
- Division of Plastic and Reconstructive Surgery, University of Miami Hospital, Miami, FL, USA
| | - Amy L Stiegler
- Department of Pharmacology, Yale University, New Haven, CT, USA
| | - Titus J Boggon
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | | | | | - Tara L Wenger
- Division of Genetic Medicine, University of Washington, Seattle, WA, USA
| | | | - Oana Caluseriu
- Department of Medical Genetics, University of Alberta, AB, Canada
| | - John A Persing
- Section of Plastic and Reconstructive Surgery, Yale University School of Medicine, New Haven, CT, USA
| | - Sheng Chih Jin
- Department of Genetics, Washington University School of Medicine, St. Louis, MO, USA
| | - Richard P Lifton
- Laboratory of Human Genetics and Genomics, The Rockefeller University, New York, NY, USA.
| | - Kristopher T Kahle
- Department of Neurosurgery, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA; Broad Institute of Harvard and Massachusetts Institute of Technology, Boston, MA, USA; Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA, USA.
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3
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Timberlake AT, Kiziltug E, Jin SC, Nelson-Williams C, Loring E, Allocco A, Marlier A, Banka S, Stuart H, Passos-Buenos MR, Rosa R, Rogatto SR, Tonne E, Stiegler AL, Boggon TJ, Alperovich M, Steinbacher D, Staffenberg DA, Flores RL, Persing JA, Kahle KT, Lifton RP. De novo mutations in the BMP signaling pathway in lambdoid craniosynostosis. Hum Genet 2023; 142:21-32. [PMID: 35997807 DOI: 10.1007/s00439-022-02477-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 08/08/2022] [Indexed: 01/18/2023]
Abstract
Lambdoid craniosynostosis (CS) is a congenital anomaly resulting from premature fusion of the cranial suture between the parietal and occipital bones. Predominantly sporadic, it is the rarest form of CS and its genetic etiology is largely unexplored. Exome sequencing of 25 kindreds, including 18 parent-offspring trios with sporadic lambdoid CS, revealed a marked excess of damaging (predominantly missense) de novo mutations that account for ~ 40% of sporadic cases. These mutations clustered in the BMP signaling cascade (P = 1.6 × 10-7), including mutations in genes encoding BMP receptors (ACVRL1 and ACVR2A), transcription factors (SOX11, FOXO1) and a transcriptional co-repressor (IFRD1), none of which have been implicated in other forms of CS. These missense mutations are at residues critical for substrate or target sequence recognition and many are inferred to cause genetic gain-of-function. Additionally, mutations in transcription factor NFIX were implicated in syndromic craniosynostosis affecting diverse sutures. Single cell RNA sequencing analysis of the mouse lambdoid suture identified enrichment of mutations in osteoblast precursors (P = 1.6 × 10-6), implicating perturbations in the balance between proliferation and differentiation of osteoprogenitor cells in lambdoid CS. The results contribute to the growing knowledge of the genetics of CS, have implications for genetic counseling, and further elucidate the molecular etiology of premature suture fusion.
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Affiliation(s)
- Andrew T Timberlake
- Hansjörg Wyss Department of Plastic Surgery, New York University Langone Medical Center, New York, NY, USA.
| | - Emre Kiziltug
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
| | - Sheng Chih Jin
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA.,Department of Genetics, Washington University School of Medicine, St Louis, MO, USA
| | | | - Erin Loring
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
| | | | - August Allocco
- Department of Neurosurgery, Yale University School of Medicine, New Haven, CT, USA
| | - Arnaud Marlier
- Department of Neurosurgery, Yale University School of Medicine, New Haven, CT, USA
| | - Siddharth Banka
- Division of Evolution and Genomic Sciences, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9WL, UK.,Manchester Centre for Genomic Medicine, Health Innovation Manchester, St Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, M13 9WL, UK
| | - Helen Stuart
- Division of Evolution and Genomic Sciences, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9WL, UK.,Manchester Centre for Genomic Medicine, Health Innovation Manchester, St Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, M13 9WL, UK
| | | | - Rafael Rosa
- Clinical Genetics, UFCSPA and Irmandade da Santa Casa de Misericórdia de Porto Alegre (ISCMPA), Porto Alegre, RS, Brazil
| | - Silvia R Rogatto
- Neogene Laboratory, Research Center (CIPE), AC Camargo Cancer Center, São Paulo, SP, Brazil
| | - Elin Tonne
- Department of Medical Genetics, Oslo University Hospital, Oslo, Norway.,University of Oslo, Oslo, Norway
| | - Amy L Stiegler
- Department of Pharmacology, Yale University, New Haven, CT, USA
| | - Titus J Boggon
- Department of Pharmacology, Yale University, New Haven, CT, USA
| | - Michael Alperovich
- Section of Plastic and Reconstructive Surgery, Yale University School of Medicine, New Haven, CT, USA
| | - Derek Steinbacher
- Section of Plastic and Reconstructive Surgery, Yale University School of Medicine, New Haven, CT, USA
| | - David A Staffenberg
- Hansjörg Wyss Department of Plastic Surgery, New York University Langone Medical Center, New York, NY, USA
| | - Roberto L Flores
- Hansjörg Wyss Department of Plastic Surgery, New York University Langone Medical Center, New York, NY, USA
| | - John A Persing
- Section of Plastic and Reconstructive Surgery, Yale University School of Medicine, New Haven, CT, USA
| | - Kristopher T Kahle
- Department of Neurosurgery, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.,Broad Institute of Harvard and Massachusetts Institute of Technology, Boston, MA, USA.,Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA, USA
| | - Richard P Lifton
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA. .,Laboratory of Human Genetics and Genomics, The Rockefeller University, New York, NY, USA.
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4
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Stiegler AL, Boggon TJ. Structure Determination of SH2-Phosphopeptide Complexes by X-Ray Crystallography: The Example of p120RasGAP. Methods Mol Biol 2023; 2705:77-89. [PMID: 37668970 PMCID: PMC11059313 DOI: 10.1007/978-1-0716-3393-9_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/06/2023]
Abstract
The p120RasGAP protein contains two Src homology 2 (SH2) domains, each with phosphotyrosine-binding activity. We describe the crystallization of the isolated and purified p120RasGAP SH2 domains with phosphopeptides derived from a binding partner protein, p190RhoGAP. Purified recombinant SH2 domain protein is mixed with synthetic phosphopeptide at a stoichiometric ratio to form the complex in vitro. Crystallization is then achieved by the hanging drop vapor diffusion method over specific reservoir solutions that yield single macromolecular co-crystals containing SH2 domain protein and phosphopeptide. This protocol yields suitable crystals for X-ray diffraction studies, and our recent X-ray crystallography studies of the two SH2 domains of p120RasGAP demonstrate that the N-terminal SH2 domain binds phosphopeptide in a canonical interaction. In contrast, the C-terminal SH2 domain binds phosphopeptide via a unique atypical binding mode. The crystallographic studies for p120RasGAP illustrate that although the three-dimensional structure of SH2 domains and the molecular details of their binding to phosphotyrosine peptides are well defined, careful structural analysis can continue to yield new molecular-level insights.
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Affiliation(s)
- Amy L Stiegler
- Department of Pharmacology, Yale University, New Haven, CT, USA
| | - Titus J Boggon
- Department of Pharmacology, Yale University, New Haven, CT, USA.
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.
- Yale Cancer Center, Yale University, New Haven, CT, USA.
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5
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Stiegler AL, Vish KJ, Boggon TJ. Tandem engagement of phosphotyrosines by the dual SH2 domains of p120RasGAP. Structure 2022; 30:1603-1614.e5. [PMID: 36417908 PMCID: PMC9722645 DOI: 10.1016/j.str.2022.10.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 09/22/2022] [Accepted: 10/27/2022] [Indexed: 11/23/2022]
Abstract
p120RasGAP is a multidomain GTPase-activating protein for Ras. The presence of two Src homology 2 domains in an SH2-SH3-SH2 module raises the possibility that p120RasGAP simultaneously binds dual phosphotyrosine residues in target proteins. One known binding partner with two proximal phosphotyrosines is p190RhoGAP, a GTPase-activating protein for Rho GTPases. Here, we present the crystal structure of the p120RasGAP SH2-SH3-SH2 module bound to a doubly tyrosine-phosphorylated p190RhoGAP peptide, revealing simultaneous phosphotyrosine recognition by the SH2 domains. The compact arrangement places the SH2 domains in close proximity resembling an SH2 domain tandem and exposed SH3 domain. Affinity measurements support synergistic binding, while solution scattering reveals that dual phosphotyrosine binding induces compaction of this region. Our studies reflect a binding mode that limits conformational flexibility within the SH2-SH3-SH2 cassette and relies on the spacing and sequence surrounding the two phosphotyrosines, potentially representing a selectivity mechanism for downstream signaling events.
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Affiliation(s)
- Amy L Stiegler
- Department of Pharmacology, Yale University, New Haven, CT, USA
| | - Kimberly J Vish
- Department of Pharmacology, Yale University, New Haven, CT, USA; Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Titus J Boggon
- Department of Pharmacology, Yale University, New Haven, CT, USA; Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA; Yale Cancer Center, Yale University, New Haven, CT, USA.
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6
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Chau JE, Vish KJ, Boggon TJ, Stiegler AL. SH3 domain regulation of RhoGAP activity: Crosstalk between p120RasGAP and DLC1 RhoGAP. Nat Commun 2022; 13:4788. [PMID: 35970859 PMCID: PMC9378701 DOI: 10.1038/s41467-022-32541-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 08/04/2022] [Indexed: 11/10/2022] Open
Abstract
RhoGAP proteins are key regulators of Rho family GTPases and influence a variety of cellular processes, including cell migration, adhesion, and cytokinesis. These GTPase activating proteins (GAPs) downregulate Rho signaling by binding and enhancing the intrinsic GTPase activity of Rho proteins. Deleted in liver cancer 1 (DLC1) is a tumor suppressor and ubiquitously expressed RhoGAP protein; its activity is regulated in part by binding p120RasGAP, a GAP protein for the Ras GTPases. In this study, we report the co-crystal structure of the p120RasGAP SH3 domain bound directly to DLC1 RhoGAP, at a site partially overlapping the RhoA binding site and impinging on the catalytic arginine finger. We demonstrate biochemically that mutation of this interface relieves inhibition of RhoGAP activity by the SH3 domain. These results reveal the mechanism for inhibition of DLC1 RhoGAP activity by p120RasGAP and demonstrate the molecular basis for direct SH3 domain modulation of GAP activity. Inhibition of DLC1 RhoGAP by p120RasGAP allows for crosstalk between the Rho and Ras pathways. Here, Chau et al. present the co-crystal structure of DLC1 RhoGAP domain and p120RasGAP SH3 domain and probe the interaction with biochemical studies.
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Affiliation(s)
- Jocelyn E Chau
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Kimberly J Vish
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.,Department of Pharmacology, Yale University, New Haven, CT, USA
| | - Titus J Boggon
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.,Department of Pharmacology, Yale University, New Haven, CT, USA
| | - Amy L Stiegler
- Department of Pharmacology, Yale University, New Haven, CT, USA.
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7
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Le Coz C, Nguyen DN, Su C, Nolan BE, Albrecht AV, Xhani S, Sun D, Demaree B, Pillarisetti P, Khanna C, Wright F, Chen PA, Yoon S, Stiegler AL, Maurer K, Garifallou JP, Rymaszewski A, Kroft SH, Olson TS, Seif AE, Wertheim G, Grant SFA, Vo LT, Puck JM, Sullivan KE, Routes JM, Zakharova V, Shcherbina A, Mukhina A, Rudy NL, Hurst ACE, Atkinson TP, Boggon TJ, Hakonarson H, Abate AR, Hajjar J, Nicholas SK, Lupski JR, Verbsky J, Chinn IK, Gonzalez MV, Wells AD, Marson A, Poon GMK, Romberg N. Constrained chromatin accessibility in PU.1-mutated agammaglobulinemia patients. J Exp Med 2021; 218:212070. [PMID: 33951726 PMCID: PMC8105723 DOI: 10.1084/jem.20201750] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 02/09/2021] [Accepted: 03/16/2021] [Indexed: 12/19/2022] Open
Abstract
The pioneer transcription factor (TF) PU.1 controls hematopoietic cell fate by decompacting stem cell heterochromatin and allowing nonpioneer TFs to enter otherwise inaccessible genomic sites. PU.1 deficiency fatally arrests lymphopoiesis and myelopoiesis in mice, but human congenital PU.1 disorders have not previously been described. We studied six unrelated agammaglobulinemic patients, each harboring a heterozygous mutation (four de novo, two unphased) of SPI1, the gene encoding PU.1. Affected patients lacked circulating B cells and possessed few conventional dendritic cells. Introducing disease-similar SPI1 mutations into human hematopoietic stem and progenitor cells impaired early in vitro B cell and myeloid cell differentiation. Patient SPI1 mutations encoded destabilized PU.1 proteins unable to nuclear localize or bind target DNA. In PU.1-haploinsufficient pro–B cell lines, euchromatin was less accessible to nonpioneer TFs critical for B cell development, and gene expression patterns associated with the pro– to pre–B cell transition were undermined. Our findings molecularly describe a novel form of agammaglobulinemia and underscore PU.1’s critical, dose-dependent role as a hematopoietic euchromatin gatekeeper.
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Affiliation(s)
- Carole Le Coz
- Division of Immunology and Allergy, Children's Hospital of Philadelphia, Philadelphia, PA
| | - David N Nguyen
- Division of Infectious Diseases, Department of Medicine, University of California San Francisco, San Francisco, CA.,Department of Microbiology and Immunology, University of California San Francisco, San Francisco, CA.,Diabetes Center, University of California San Francisco, San Francisco, CA.,Innovative Genomics Institute, University of California Berkeley, Berkeley, CA.,Gladstone-University of California San Francisco Institute of Genomic Immunology, San Francisco, CA
| | - Chun Su
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA.,Center for Spatial and Functional Genomics, Children's Hospital of Philadelphia, Philadelphia, PA
| | - Brian E Nolan
- Division of Rheumatology, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL.,Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, IL
| | - Amanda V Albrecht
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA
| | - Suela Xhani
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA
| | - Di Sun
- Division of Immunology and Allergy, Children's Hospital of Philadelphia, Philadelphia, PA
| | - Benjamin Demaree
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA.,University of California Berkeley-University of California San Francisco Graduate Program in Bioengineering, University of California, San Francisco, CA
| | - Piyush Pillarisetti
- Division of Immunology and Allergy, Children's Hospital of Philadelphia, Philadelphia, PA
| | - Caroline Khanna
- Division of Immunology and Allergy, Children's Hospital of Philadelphia, Philadelphia, PA
| | - Francis Wright
- Division of Infectious Diseases, Department of Medicine, University of California San Francisco, San Francisco, CA.,Department of Microbiology and Immunology, University of California San Francisco, San Francisco, CA
| | - Peixin Amy Chen
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, CA.,Diabetes Center, University of California San Francisco, San Francisco, CA.,Innovative Genomics Institute, University of California Berkeley, Berkeley, CA.,Gladstone-University of California San Francisco Institute of Genomic Immunology, San Francisco, CA
| | - Samuel Yoon
- Division of Immunology and Allergy, Children's Hospital of Philadelphia, Philadelphia, PA
| | - Amy L Stiegler
- Departments of Pharmacology, Yale University, New Haven, CT
| | - Kelly Maurer
- Division of Immunology and Allergy, Children's Hospital of Philadelphia, Philadelphia, PA
| | - James P Garifallou
- Center for Applied Genomics, Children's Hospital of Philadelphia, Philadelphia, PA
| | - Amy Rymaszewski
- Division of Allergy and Immunology, Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI
| | - Steven H Kroft
- Department of Pathology, Medical College of Wisconsin, Milwaukee, WI
| | - Timothy S Olson
- Division of Oncology, Children's Hospital of Philadelphia, Philadelphia, PA.,Department of Pediatrics, Perelman School of Medicine, Philadelphia, PA
| | - Alix E Seif
- Division of Oncology, Children's Hospital of Philadelphia, Philadelphia, PA.,Department of Pediatrics, Perelman School of Medicine, Philadelphia, PA
| | - Gerald Wertheim
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA.,Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Struan F A Grant
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA.,Department of Pediatrics, Perelman School of Medicine, Philadelphia, PA.,Division of Diabetes and Endocrinology, Children's Hospital of Philadelphia, Philadelphia, PA.,Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Linda T Vo
- Diabetes Center, University of California San Francisco, San Francisco, CA.,Innovative Genomics Institute, University of California Berkeley, Berkeley, CA
| | - Jennifer M Puck
- Division of Allergy, Immunology, and Bone Marrow Transplantation, Department of Pediatrics, University of California, San Francisco, CA.,University of California San Francsico Institute for Human Genetics and Smith Cardiovascular Research Institute, University of California, San Francisco, CA.,UCSF Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, San Francisco, CA
| | - Kathleen E Sullivan
- Division of Immunology and Allergy, Children's Hospital of Philadelphia, Philadelphia, PA.,Department of Pediatrics, Perelman School of Medicine, Philadelphia, PA.,Institute for Immunology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - John M Routes
- Division of Allergy and Immunology, Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI
| | - Viktoria Zakharova
- Laboratory of Molecular Biology, Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology, Moscow, Russia
| | - Anna Shcherbina
- Department of Immunology, Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology, Moscow, Russia
| | - Anna Mukhina
- Department of Immunology, Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology, Moscow, Russia
| | - Natasha L Rudy
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL
| | - Anna C E Hurst
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL.,Department of Pediatrics, University of Alabama at Birmingham, Birmingham, AL
| | - T Prescott Atkinson
- Department of Pediatrics, University of Alabama at Birmingham, Birmingham, AL
| | - Titus J Boggon
- Departments of Pharmacology, Yale University, New Haven, CT.,Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT
| | - Hakon Hakonarson
- Center for Applied Genomics, Children's Hospital of Philadelphia, Philadelphia, PA.,Department of Pediatrics, Perelman School of Medicine, Philadelphia, PA
| | - Adam R Abate
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA.,University of California Berkeley-University of California San Francisco Graduate Program in Bioengineering, University of California, San Francisco, CA.,Chan Zuckerberg Biohub, San Francisco, CA
| | - Joud Hajjar
- William T. Shearer Center for Human Immunobiology, Texas Children's Hospital, Houston, TX.,Department of Immunology, Allergy and Rheumatology, Baylor College of Medicine, Houston, TX
| | - Sarah K Nicholas
- William T. Shearer Center for Human Immunobiology, Texas Children's Hospital, Houston, TX.,Department of Immunology, Allergy and Rheumatology, Baylor College of Medicine, Houston, TX
| | - James R Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX.,Texas Children's Hospital, Houston, TX.,Baylor-Hopkins Center for Mendelian Genomics, Houston, TX
| | - James Verbsky
- Division of Allergy and Immunology, Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI
| | - Ivan K Chinn
- William T. Shearer Center for Human Immunobiology, Texas Children's Hospital, Houston, TX.,Department of Immunology, Allergy and Rheumatology, Baylor College of Medicine, Houston, TX
| | - Michael V Gonzalez
- Center for Applied Genomics, Children's Hospital of Philadelphia, Philadelphia, PA
| | - Andrew D Wells
- Center for Spatial and Functional Genomics, Children's Hospital of Philadelphia, Philadelphia, PA.,Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA.,Institute for Immunology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Alex Marson
- Division of Infectious Diseases, Department of Medicine, University of California San Francisco, San Francisco, CA.,Department of Microbiology and Immunology, University of California San Francisco, San Francisco, CA.,Diabetes Center, University of California San Francisco, San Francisco, CA.,Innovative Genomics Institute, University of California Berkeley, Berkeley, CA.,Gladstone-University of California San Francisco Institute of Genomic Immunology, San Francisco, CA.,Chan Zuckerberg Biohub, San Francisco, CA.,Parker Institute for Cancer Immunotherapy, San Francisco, CA
| | - Gregory M K Poon
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA
| | - Neil Romberg
- Division of Immunology and Allergy, Children's Hospital of Philadelphia, Philadelphia, PA.,Department of Pediatrics, Perelman School of Medicine, Philadelphia, PA.,Institute for Immunology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
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8
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Abstract
Pseudoenzymes are emerging as significant mediators and regulators of signal transduction. These proteins maintain enzyme folds and topologies, but are disrupted in the conserved motifs required for enzymatic activity. Among the pseudoenzymes, the pseudoGTPase group of atypical GTPases has recently expanded and includes the Rnd and RGK groups, RhoH and the RhoBTB proteins, mitochondrial RhoGTPase and centaurin-γ groups, CENP-M, dynein LIC, Entamoeba histolytica RabX3, leucine-rich repeat kinase 2, and the p190RhoGAP proteins. The wide range of cellular functions associated with pseudoGTPases includes cell migration and adhesion, membrane trafficking and cargo transport, mitosis, mitochondrial activity, transcriptional control, and autophagy, placing the group in an expanding portfolio of signaling pathways. In this review, we examine how the pseudoGTPases differ from canonical GTPases and consider their mechanistic and functional roles in signal transduction. We review the amino acid differences between the pseudoGTPases and discuss how these proteins can be classified based on their ability to bind nucleotide and their enzymatic activity. We discuss the molecular and structural consequences of amino acid divergence from canonical GTPases and use comparison with the well-studied pseudokinases to illustrate the classifications. PseudoGTPases are fast becoming recognized as important mechanistic components in a range of cellular roles, and we provide a concise discussion of the currently identified members of this group. ENZYMES: small GTPases; EC number: EC 3.6.5.2.
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Affiliation(s)
- Amy L. Stiegler
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06520, USA
| | - Titus J. Boggon
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06520, USA
- Departments of Molecular Biophysics and Biochemistry, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06520, USA
- Yale Cancer Center, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06520, USA
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9
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Jaber Chehayeb R, Wang J, Stiegler AL, Boggon TJ. The GTPase-activating protein p120RasGAP has an evolutionarily conserved "FLVR-unique" SH2 domain. J Biol Chem 2020; 295:10511-10521. [PMID: 32540970 PMCID: PMC7397115 DOI: 10.1074/jbc.ra120.013976] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 06/09/2020] [Indexed: 01/07/2023] Open
Abstract
The Src homology 2 (SH2) domain has a highly conserved architecture that recognizes linear phosphotyrosine motifs and is present in a wide range of signaling pathways across different evolutionary taxa. A hallmark of SH2 domains is the arginine residue in the conserved FLVR motif that forms a direct salt bridge with bound phosphotyrosine. Here, we solve the X-ray crystal structures of the C-terminal SH2 domain of p120RasGAP (RASA1) in its apo and peptide-bound form. We find that the arginine residue in the FLVR motif does not directly contact pTyr1087 of a bound phosphopeptide derived from p190RhoGAP; rather, it makes an intramolecular salt bridge to an aspartic acid. Unexpectedly, coordination of phosphotyrosine is achieved by a modified binding pocket that appears early in evolution. Using isothermal titration calorimetry, we find that substitution of the FLVR arginine R377A does not cause a significant loss of phosphopeptide binding, but rather a tandem substitution of R398A (SH2 position βD4) and K400A (SH2 position βD6) is required to disrupt the binding. These results indicate a hitherto unrecognized diversity in SH2 domain interactions with phosphotyrosine and classify the C-terminal SH2 domain of p120RasGAP as "FLVR-unique."
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Affiliation(s)
- Rachel Jaber Chehayeb
- Yale College, New Haven, Connecticut, USA
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | - Jessica Wang
- Yale College, New Haven, Connecticut, USA
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | - Amy L Stiegler
- Department of Pharmacology, Yale University, New Haven, Connecticut, USA
| | - Titus J Boggon
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
- Department of Pharmacology, Yale University, New Haven, Connecticut, USA
- Yale Cancer Center, Yale University, New Haven, Connecticut, USA
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10
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Jaber Chehayeb R, Stiegler AL, Boggon TJ. Correction: Crystal structures of p120RasGAP N-terminal SH2 domain in its apo form and in complex with a p190RhoGAP phosphotyrosine peptide. PLoS One 2020; 15:e0229627. [PMID: 32078652 PMCID: PMC7032684 DOI: 10.1371/journal.pone.0229627] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
[This corrects the article DOI: 10.1371/journal.pone.0226113.].
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11
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Jaber Chehayeb R, Stiegler AL, Boggon TJ. Crystal structures of p120RasGAP N-terminal SH2 domain in its apo form and in complex with a p190RhoGAP phosphotyrosine peptide. PLoS One 2019; 14:e0226113. [PMID: 31891593 PMCID: PMC6938330 DOI: 10.1371/journal.pone.0226113] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 11/19/2019] [Indexed: 01/26/2023] Open
Abstract
The Rho and Ras pathways play vital roles in cell growth, division and motility. Cross-talk between the pathways amplifies their roles in cell proliferation and motility and its dysregulation is involved in disease pathogenesis. One important interaction for cross-talk occurs between p120RasGAP (RASA1), a GTPase activating protein (GAP) for Ras, and p190RhoGAP (p190RhoGAP-A, ARHGAP35), a GAP for Rho. The binding of these proteins is primarily mediated by two SH2 domains within p120RasGAP engaging phosphorylated tyrosines of p190RhoGAP, of which the best studied is pTyr-1105. To better understand the interaction between p120RasGAP and p190RhoGAP, we determined the 1.75 Å X-ray crystal structure of the N-terminal SH2 domain of p120RasGAP in the unliganded form, and its 1.6 Å co-crystal structure in complex with a synthesized phosphotyrosine peptide, EEENI(p-Tyr)SVPHDST, corresponding to residues 1100–1112 of p190RhoGAP. We find that the N-terminal SH2 domain of p120RhoGAP has the characteristic SH2 fold encompassing a central beta-sheet flanked by two alpha-helices, and that peptide binding stabilizes specific conformations of the βE-βF loop and arginine residues R212 and R231. Site-directed mutagenesis and native gel shifts confirm phosphotyrosine binding through the conserved FLVR motif arginine residue R207, and isothermal titration calorimetry finds a dissociation constant of 0.3 ± 0.1 μM between the phosphopeptide and SH2 domain. These results demonstrate that the major interaction between two important GAP proteins, p120RasGAP and p190RhoGAP, is mediated by a canonical SH2-pTyr interaction.
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Affiliation(s)
- Rachel Jaber Chehayeb
- Yale College, New Haven, Connecticut, United States of America
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, United States of America
| | - Amy L. Stiegler
- Department of Pharmacology, Yale University, New Haven, Connecticut, United States of America
| | - Titus J. Boggon
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, United States of America
- Department of Pharmacology, Yale University, New Haven, Connecticut, United States of America
- Yale Cancer Center, Yale University, New Haven, Connecticut, United States of America
- * E-mail:
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12
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Brodehl A, Rezazadeh S, Williams T, Munsie NM, Liedtke D, Oh T, Ferrier R, Shen Y, Jones SJM, Stiegler AL, Boggon TJ, Duff HJ, Friedman JM, Gibson WT, Childs SJ, Gerull B. Mutations in ILK, encoding integrin-linked kinase, are associated with arrhythmogenic cardiomyopathy. Transl Res 2019; 208:15-29. [PMID: 30802431 PMCID: PMC7412573 DOI: 10.1016/j.trsl.2019.02.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 01/17/2019] [Accepted: 02/12/2019] [Indexed: 12/11/2022]
Abstract
Arrhythmogenic cardiomyopathy is a genetic heart muscle disorder characterized by fibro-fatty replacement of cardiomyocytes leading to life-threatening ventricular arrhythmias, heart failure, and sudden cardiac death. Mutations in genes encoding cardiac junctional proteins are known to cause about half of cases, while remaining genetic causes are unknown. Using exome sequencing, we identified 2 missense variants (p.H33N and p.H77Y) that were predicted to be damaging in the integrin-linked kinase (ILK) gene in 2 unrelated families. The p.H33N variant was found to be de novo. ILK links integrins and the actin cytoskeleton, and is essential for the maintenance of normal cardiac function. Both of the new variants are located in the ILK ankyrin repeat domain, which binds to the first LIM domain of the adaptor proteins PINCH1 and PINCH2. In silico binding studies proposed that the human variants disrupt the ILK-PINCH complex. Recombinant mutant ILK expressed in H9c2 rat myoblast cells shows aberrant prominent cytoplasmic localization compared to the wild-type. Expression of human wild-type and mutant ILK under the control of the cardiac-specific cmlc2 promotor in zebrafish shows that p.H77Y and p.P70L, a variant previously reported in a dilated cardiomyopathy family, cause cardiac dysfunction and death by about 2-3 weeks of age. Our findings provide genetic and functional evidence that ILK is a cardiomyopathy disease gene and highlight its relevance for diagnosis and genetic counseling of inherited cardiomyopathies.
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Affiliation(s)
- Andreas Brodehl
- Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - Saman Rezazadeh
- Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - Tatjana Williams
- Comprehensive Heart Failure Center and Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany
| | - Nicole M Munsie
- Department of Biochemistry and Molecular Biology, Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
| | - Daniel Liedtke
- Institute of Human Genetics, Julius-Maximilians-Universität Würzburg, Würzburg, Germany
| | - Tracey Oh
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Raechel Ferrier
- Department of Medical Genetics, Alberta Health Services, Calgary, Alberta, Canada
| | - Yaoqing Shen
- Canada's Michael Smith Genome Sciences Centre, Vancouver, British Columbia, Canada
| | - Steven J M Jones
- Canada's Michael Smith Genome Sciences Centre, Vancouver, British Columbia, Canada
| | - Amy L Stiegler
- Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Titus J Boggon
- Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Henry J Duff
- Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - Jan M Friedman
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - William T Gibson
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada; BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada
| | | | - Sarah J Childs
- Department of Biochemistry and Molecular Biology, Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
| | - Brenda Gerull
- Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada; Comprehensive Heart Failure Center and Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany.
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13
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Stiegler AL, Boggon TJ. The N-Terminal GTPase Domain of p190RhoGAP Proteins Is a PseudoGTPase. Structure 2018; 26:1451-1461.e4. [PMID: 30174148 DOI: 10.1016/j.str.2018.07.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 06/28/2018] [Accepted: 07/25/2018] [Indexed: 12/29/2022]
Abstract
The pseudoGTPases are a rapidly growing and important group of pseudoenzymes. p190RhoGAP proteins are critical regulators of Rho signaling and contain two previously identified pseudoGTPase domains. Here we report that p190RhoGAP proteins contain a third pseudoGTPase domain, termed N-GTPase. We find that GTP constitutively purifies with the N-GTPase domain, and a 2.8-Å crystal structure of p190RhoGAP-A co-purified with GTP reveals an unusual GTP-Mg2+ binding pocket. Six inserts in N-GTPase indicate perturbed catalytic activity and inability to bind to canonical GTPase activating proteins, guanine nucleotide exchange factors, and effector proteins. Biochemical analysis shows that N-GTPase does not detectably hydrolyze GTP, and exchanges nucleotide only under harsh Mg2+ chelation. Furthermore, mutational analysis shows that GTP and Mg2+ binding stabilizes the domain. Therefore, our results support that N-GTPase is a nucleotide binding, non-hydrolyzing, pseudoGTPase domain that may act as a protein-protein interaction domain. Thus, unique among known proteins, p190RhoGAPs contain three pseudoGTPase domains.
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Affiliation(s)
- Amy L Stiegler
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Titus J Boggon
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA; Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA; Yale Cancer Center, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA.
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14
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Vilarinho S, Sari S, Yilmaz G, Stiegler AL, Boggon TJ, Jain D, Akyol G, Dalgic B, Günel M, Lifton RP. Recurrent recessive mutation in deoxyguanosine kinase causes idiopathic noncirrhotic portal hypertension. Hepatology 2016; 63:1977-86. [PMID: 26874653 PMCID: PMC4874872 DOI: 10.1002/hep.28499] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2015] [Accepted: 02/10/2016] [Indexed: 12/30/2022]
Abstract
UNLABELLED Despite advances in the diagnosis and management of idiopathic noncirrhotic portal hypertension, its pathogenesis remains elusive. Insight may be gained from study of early-onset familial idiopathic noncirrhotic portal hypertension, in which Mendelian mutations may account for disease. We performed exome sequencing of eight subjects from six kindreds with onset of portal hypertension of indeterminate etiology during infancy or childhood. Three subjects from two consanguineous families shared the identical rare homozygous p.N46S mutation in DGUOK, a deoxyguanosine kinase required for mitochondrial DNA replication; haplotype sharing demonstrated that the mutation in the two families was inherited from a remote common ancestor. All three affected subjects had stable portal hypertension with noncirrhotic liver disease for 6-16 years of follow-up. This mutation impairs adenosine triphosphate binding and reduces catalytic activity. Loss-of-function mutations in DGUOK have previously been implicated in cirrhosis and liver failure but not in isolated portal hypertension. Interestingly, treatment of patients with human immunodeficiency viral infection with the nucleoside analogue didanosine is known to cause portal hypertension in a subset of patients and lowers deoxyguanosine kinase levels in vitro; the current findings implicate these effects on deoxyguanosine kinase in the causal mechanism. CONCLUSION Our findings provide new insight into the mechanisms mediating inherited and acquired noncirrhotic portal hypertension, expand the phenotypic spectrum of DGUOK deficiency, and provide a new genetic test for a specific cause of idiopathic noncirrhotic portal hypertension. (Hepatology 2016;63:1977-1986).
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Affiliation(s)
- Sílvia Vilarinho
- Department of Internal Medicine, Section of Digestive Diseases, Yale University School of Medicine, New Haven, Connecticut, USA,Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, USA,Correspondence should be addressed to: Richard P. Lifton, M.D., Ph.D., Departments of Genetics and Internal Medicine, Howard Hughes Medical Institute, Yale University School of Medicine, 333 Cedar St., SHM I308, New Haven, CT 06510, USA. Telephone: +1-203-737-4420, Fax: +1-203-785-7560, ; or Sílvia Vilarinho, M.D., Ph.D., Departments of Genetics and Internal Medicine, Section of Digestive Diseases, Yale University School of Medicine, 333 Cedar St., LMP1080, New Haven, CT 06510, USA. Telephone: +1-203-737-1833, Fax: +1-203-737-1755,
| | - Sinan Sari
- Department of Pediatrics, Division of Gastroenterology, Gazi University, Faculty of Medicine, Ankara, Turkey
| | - Güldal Yilmaz
- Department of Pathology, Gazi University, Faculty of Medicine, Ankara, Turkey
| | - Amy L. Stiegler
- Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Titus J. Boggon
- Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut, USA,Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | - Dhanpat Jain
- Department of Internal Medicine, Section of Digestive Diseases, Yale University School of Medicine, New Haven, Connecticut, USA,Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, USA,Department of Pathology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Gulen Akyol
- Department of Pathology, Gazi University, Faculty of Medicine, Ankara, Turkey
| | - Buket Dalgic
- Department of Pediatrics, Division of Gastroenterology, Gazi University, Faculty of Medicine, Ankara, Turkey
| | - Murat Günel
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, USA,Department of Neurosurgery, Yale Program in Brain Tumor Research, Yale University School of Medicine, New Haven, Connecticut, USA,Yale Center for Mendelian Genomics, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Richard P. Lifton
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, USA,Department of Neurosurgery, Yale Program in Brain Tumor Research, Yale University School of Medicine, New Haven, Connecticut, USA,Department of Internal Medicine and Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut, USA,Correspondence should be addressed to: Richard P. Lifton, M.D., Ph.D., Departments of Genetics and Internal Medicine, Howard Hughes Medical Institute, Yale University School of Medicine, 333 Cedar St., SHM I308, New Haven, CT 06510, USA. Telephone: +1-203-737-4420, Fax: +1-203-785-7560, ; or Sílvia Vilarinho, M.D., Ph.D., Departments of Genetics and Internal Medicine, Section of Digestive Diseases, Yale University School of Medicine, 333 Cedar St., LMP1080, New Haven, CT 06510, USA. Telephone: +1-203-737-1833, Fax: +1-203-737-1755,
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15
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Fisher OS, Liu W, Zhang R, Stiegler AL, Ghedia S, Weber JL, Boggon TJ. Structural basis for the disruption of the cerebral cavernous malformations 2 (CCM2) interaction with Krev interaction trapped 1 (KRIT1) by disease-associated mutations. J Biol Chem 2014; 290:2842-53. [PMID: 25525273 DOI: 10.1074/jbc.m114.616433] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Familial cerebral cavernous malformations (CCMs) are predominantly neurovascular lesions and are associated with mutations within the KRIT1, CCM2, and PDCD10 genes. The protein products of KRIT1 and CCM2 (Krev interaction trapped 1 (KRIT1) and cerebral cavernous malformations 2 (CCM2), respectively) directly interact with each other. Disease-associated mutations in KRIT1 and CCM2 mostly result in loss of their protein products, although rare missense point mutations can also occur. From gene sequencing of patients known or suspected to have one or more CCMs, we discover a series of missense point mutations in KRIT1 and CCM2 that result in missense mutations in the CCM2 and KRIT1 proteins. To place these mutations in the context of the molecular level interactions of CCM2 and KRIT1, we map the interaction of KRIT1 and CCM2 and find that the CCM2 phosphotyrosine binding (PTB) domain displays a preference toward the third of the three KRIT1 NPX(Y/F) motifs. We determine the 2.75 Å co-crystal structure of the CCM2 PTB domain with a peptide corresponding to KRIT1(NPX(Y/F)3), revealing a Dab-like PTB fold for CCM2 and its interaction with KRIT1(NPX(Y/F)3). We find that several disease-associated missense mutations in CCM2 have the potential to interrupt the KRIT1-CCM2 interaction by destabilizing the CCM2 PTB domain and that a KRIT1 mutation also disrupts this interaction. We therefore provide new insights into the architecture of CCM2 and how the CCM complex is disrupted in CCM disease.
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Affiliation(s)
- Oriana S Fisher
- From the Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Weizhi Liu
- From the Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Rong Zhang
- From the Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Amy L Stiegler
- From the Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Sondhya Ghedia
- the Department of Clinical Genetics, Royal North Shore Hospital, Pacific Highway, St. Leonards, New South Wales 2065, Australia, and
| | | | - Titus J Boggon
- From the Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520,
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16
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Romberg N, Al Moussawi K, Nelson-Williams C, Stiegler AL, Loring E, Choi M, Overton J, Meffre E, Khokha MK, Huttner AJ, West B, Podoltsev NA, Boggon TJ, Kazmierczak BI, Lifton RP. Mutation of NLRC4 causes a syndrome of enterocolitis and autoinflammation. Nat Genet 2014; 46:1135-1139. [PMID: 25217960 PMCID: PMC4177367 DOI: 10.1038/ng.3066] [Citation(s) in RCA: 342] [Impact Index Per Article: 34.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Accepted: 07/23/2014] [Indexed: 12/16/2022]
Abstract
Upon detection of pathogen-associated molecular patterns, innate immune receptors initiate inflammatory responses. These receptors include cytoplasmic NOD-like receptors (NLRs), whose stimulation recruits and proteolytically activates caspase-1 within the inflammasome, a multi-protein complex. Caspase-1 mediates the production of interleukin-1 family cytokines (IL1FCs), leading to fever, and inflammatory cell death (pyroptosis)1,2. Mutations that constitutively activate these pathways underlie several autoinflammatory diseases with diverse clinical features3. We describe a family with a previously unreported syndrome featuring neonatal-onset enterocolitis, periodic fever, and fatal/near-fatal episodes of autoinflammation caused by a de novo gain-of-function mutation (p.V341A) in the HD1 domain of NLRC4 that co-segregates with disease. Mutant NLRC4 causes constitutive Interleukin-1 family cytokine production and macrophage cell death. Infected patient macrophages are polarized toward pyroptosis and exhibit abnormal staining for inflammasome components. These findings describe and reveal the cause of a life-threatening but treatable autoinflammatory disease that underscores the divergent roles of the NLRC4 inflammasome.
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Affiliation(s)
- Neil Romberg
- Department of Pediatrics, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06510, USA
| | - Khatoun Al Moussawi
- Department of Internal Medicine, Yale University School of Medicine, 330 Cedar Street, New Haven, Connecticut 06510, USA
| | - Carol Nelson-Williams
- Department of Genetics, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06510, USA.,Howard Hughes Medical Institute, Yale University School of Medicine, 295 Congress Avenue, New Haven, Connecticut 06510, USA
| | - Amy L Stiegler
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06510, USA
| | - Erin Loring
- Department of Genetics, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06510, USA
| | - Murim Choi
- Department of Genetics, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06510, USA.,Howard Hughes Medical Institute, Yale University School of Medicine, 295 Congress Avenue, New Haven, Connecticut 06510, USA
| | - John Overton
- Department of Genetics, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06510, USA
| | - Eric Meffre
- Department of Internal Medicine, Yale University School of Medicine, 330 Cedar Street, New Haven, Connecticut 06510, USA.,Department of Immunobiology, Yale University School of Medicine, 300 Cedar Street, New Haven, Connecticut 06510, USA
| | - Mustafa K Khokha
- Department of Pediatrics, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06510, USA.,Department of Genetics, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06510, USA
| | - Anita J Huttner
- Department of Pathology, Yale University School of Medicine, 310 Cedar Street, New Haven, Connecticut 06510, USA
| | - Brian West
- Department of Pathology, Yale University School of Medicine, 310 Cedar Street, New Haven, Connecticut 06510, USA
| | - Nikolai A Podoltsev
- Department of Internal Medicine, Yale University School of Medicine, 330 Cedar Street, New Haven, Connecticut 06510, USA
| | - Titus J Boggon
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06510, USA
| | - Barbara I Kazmierczak
- Department of Internal Medicine, Yale University School of Medicine, 330 Cedar Street, New Haven, Connecticut 06510, USA.,Department of Microbial Pathogenesis, Yale University School of Medicine, 295 Congress Ave, New Haven, Connecticut 06520, USA
| | - Richard P Lifton
- Department of Internal Medicine, Yale University School of Medicine, 330 Cedar Street, New Haven, Connecticut 06510, USA.,Department of Genetics, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06510, USA.,Howard Hughes Medical Institute, Yale University School of Medicine, 295 Congress Avenue, New Haven, Connecticut 06510, USA
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17
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Huet-Calderwood C, Brahme NN, Kumar N, Stiegler AL, Raghavan S, Boggon TJ, Calderwood DA. Differences in binding to the ILK complex determines kindlin isoform adhesion localization and integrin activation. J Cell Sci 2014; 127:4308-21. [PMID: 25086068 DOI: 10.1242/jcs.155879] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Kindlins are essential FERM-domain-containing focal adhesion (FA) proteins required for proper integrin activation and signaling. Despite the widely accepted importance of each of the three mammalian kindlins in cell adhesion, the molecular basis for their function has yet to be fully elucidated, and the functional differences between isoforms have generally not been examined. Here, we report functional differences between kindlin-2 and -3 (also known as FERMT2 and FERMT3, respectively); GFP-tagged kindlin-2 localizes to FAs whereas kindlin-3 does not, and kindlin-2, but not kindlin-3, can rescue α5β1 integrin activation defects in kindlin-2-knockdown fibroblasts. Using chimeric kindlins, we show that the relatively uncharacterized kindlin-2 F2 subdomain drives FA targeting and integrin activation. We find that the integrin-linked kinase (ILK)-PINCH-parvin complex binds strongly to the kindlin-2 F2 subdomain but poorly to that of kindlin-3. Using a point-mutated kindlin-2, we establish that efficient kindlin-2-mediated integrin activation and FA targeting require binding to the ILK complex. Thus, ILK-complex binding is crucial for normal kindlin-2 function and differential ILK binding contributes to kindlin isoform specificity.
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Affiliation(s)
| | - Nina N Brahme
- Department of Cell Biology, Yale University, New Haven, CT 06520, USA
| | - Nikit Kumar
- Department of Cell Biology, Yale University, New Haven, CT 06520, USA
| | - Amy L Stiegler
- Department of Pharmacology, Yale University, New Haven, CT 06520, USA
| | - Srikala Raghavan
- Department of Pharmacology, Yale University, New Haven, CT 06520, USA Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, Karnataka 560065, India
| | - Titus J Boggon
- Department of Pharmacology, Yale University, New Haven, CT 06520, USA
| | - David A Calderwood
- Department of Pharmacology, Yale University, New Haven, CT 06520, USA Department of Cell Biology, Yale University, New Haven, CT 06520, USA
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18
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Stiegler AL, Zhang R, Liu W, Boggon TJ. Structural determinants for binding of sorting nexin 17 (SNX17) to the cytoplasmic adaptor protein Krev interaction trapped 1 (KRIT1). J Biol Chem 2014; 289:25362-73. [PMID: 25059659 DOI: 10.1074/jbc.m114.584011] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Sorting nexin 17 (SNX17) is a member of the family of cytoplasmic sorting nexin adaptor proteins that regulate endosomal trafficking of cell surface proteins. SNX17 localizes to early endosomes where it directly binds NPX(Y/F) motifs in the cytoplasmic tails of its target receptors to mediate their rates of endocytic internalization, recycling, and/or degradation. SNX17 has also been implicated in mediating cell signaling and can interact with cytoplasmic proteins. KRIT1 (Krev interaction trapped 1), a cytoplasmic adaptor protein associated with cerebral cavernous malformations, has previously been shown to interact with SNX17. Here, we demonstrate that SNX17 indeed binds directly to KRIT1 and map the binding to the second Asn-Pro-Xaa-Tyr/Phe (NPX(Y/F)) motif in KRIT1. We further characterize the interaction as being mediated by the FERM domain of SNX17. We present the co-crystal structure of SNX17-FERM with the KRIT1-NPXF2 peptide to 3.0 Å resolution and demonstrate that the interaction is highly similar in structure and binding affinity to that between SNX17 and P-selectin. We verify the molecular details of the interaction by site-directed mutagenesis and pulldown assay and thereby confirm that the major binding site for SNX17 is confined to the NPXF2 motif in KRIT1. Taken together, our results verify a direct interaction between SNX17 and KRIT1 and classify KRIT1 as a SNX17 binding partner.
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Affiliation(s)
- Amy L Stiegler
- From the Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Rong Zhang
- From the Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Weizhi Liu
- From the Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Titus J Boggon
- From the Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520
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19
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Choi J, Landrette SF, Wang T, Evans P, Bacchiocchi A, Bjornson R, Cheng E, Stiegler AL, Gathiaka S, Acevedo O, Boggon TJ, Krauthammer M, Halaban R, Xu T. Identification of PLX4032-resistance mechanisms and implications for novel RAF inhibitors. Pigment Cell Melanoma Res 2014; 27:253-62. [PMID: 24283590 PMCID: PMC4065135 DOI: 10.1111/pcmr.12197] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Accepted: 11/26/2013] [Indexed: 02/02/2023]
Abstract
BRAF inhibitors improve melanoma patient survival, but resistance invariably develops. Here we report the discovery of a novel BRAF mutation that confers resistance to PLX4032 employing whole-exome sequencing of drug-resistant BRAFV600K melanoma cells. We further describe a new screening approach, a genome-wide piggyBac mutagenesis screen that revealed clinically relevant aberrations (N-terminal BRAF truncations and CRAF overexpression). The novel BRAF mutation, a Leu505 to His substitution (BRAFL505H), is the first resistance-conferring second-site mutation identified in BRAF mutant cells. The mutation replaces a small nonpolar amino acid at the BRAF-PLX4032 interface with a larger polar residue. Moreover, we show that BRAFL505H, found in human prostate cancer, is itself a MAPK-activating, PLX4032-resistant oncogenic mutation. Lastly, we demonstrate that the PLX4032-resistant melanoma cells are sensitive to novel, next-generation BRAF inhibitors, especially the ‘paradox-blocker’ PLX8394, supporting its use in clinical trials for treatment of melanoma patients with BRAF-mutations.
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Affiliation(s)
- Jaehyuk Choi
- Department of Dermatology, Yale University School of Medicine, New Haven, CT, USA
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20
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Shibata S, Rinehart J, Zhang J, Moeckel G, Castañeda-Bueno M, Stiegler AL, Boggon TJ, Gamba G, Lifton RP. Mineralocorticoid receptor phosphorylation regulates ligand binding and renal response to volume depletion and hyperkalemia. Cell Metab 2013; 18:660-71. [PMID: 24206662 PMCID: PMC3909709 DOI: 10.1016/j.cmet.2013.10.005] [Citation(s) in RCA: 133] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 07/29/2013] [Accepted: 09/16/2013] [Indexed: 12/30/2022]
Abstract
Nuclear receptors are transcription factors that regulate diverse cellular processes. In canonical activation, ligand availability is sufficient to produce receptor binding, entraining downstream signaling. The mineralocorticoid receptor (MR) is normally activated by aldosterone, which is produced in both volume depletion and hyperkalemia, states that require different homeostatic responses. We report phosphorylation at S843 in the MR ligand-binding domain that prevents ligand binding and activation. In kidney, MR(S843-P) is found exclusively in intercalated cells of the distal nephron. In volume depletion, angiotensin II and WNK4 signaling decrease MR(S843-P) levels, whereas hyperkalemia increases MR(S843-P). Dephosphorylation of MR(S843-P) results in aldosterone-dependent increases of the intercalated cell apical proton pump and Cl(-)/HCO3(-) exchangers, increasing Cl(-) reabsorption and promoting increased plasma volume while inhibiting K(+) secretion. These findings reveal a mechanism regulating nuclear hormone receptor activity and implicate selective MR activation in intercalated cells in the distinct adaptive responses to volume depletion and hyperkalemia.
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Affiliation(s)
- Shigeru Shibata
- Department of Genetics and Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06510, USA
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21
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Stiegler AL, Draheim KM, Li X, Chayen NE, Calderwood DA, Boggon TJ. Structural basis for paxillin binding and focal adhesion targeting of β-parvin. J Biol Chem 2012; 287:32566-77. [PMID: 22869380 DOI: 10.1074/jbc.m112.367342] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
β-Parvin is a cytoplasmic adaptor protein that localizes to focal adhesions where it interacts with integrin-linked kinase and is involved in linking integrin receptors to the cytoskeleton. It has been reported that despite high sequence similarity to α-parvin, β-parvin does not bind paxillin, suggesting distinct interactions and cellular functions for these two closely related parvins. Here, we reveal that β-parvin binds directly and specifically to leucine-aspartic acid repeat (LD) motifs in paxillin via its C-terminal calponin homology (CH2) domain. We present the co-crystal structure of β-parvin CH2 domain in complex with paxillin LD1 motif to 2.9 Å resolution and find that the interaction is similar to that previously observed between α-parvin and paxillin LD1. We also present crystal structures of unbound β-parvin CH2 domain at 2.1 Å and 2.0 Å resolution that show significant conformational flexibility in the N-terminal α-helix, suggesting an induced fit upon paxillin binding. We find that β-parvin has specificity for the LD1, LD2, and LD4 motifs of paxillin, with K(D) values determined to 27, 42, and 73 μM, respectively, by surface plasmon resonance. Furthermore, we show that proper localization of β-parvin to focal adhesions requires both the paxillin and integrin-linked kinase binding sites and that paxillin is important for early targeting of β-parvin. These studies provide the first molecular details of β-parvin binding to paxillin and help define the requirements for β-parvin localization to focal adhesions.
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Affiliation(s)
- Amy L Stiegler
- Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520, USA
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22
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Abstract
The development of EGFR tyrosine kinase inhibitors for clinical use in non-small cell lung cancer and the subsequent discovery of activating EGFR mutations have led to an explosion of knowledge in the fields of EGFR biology, targeted therapeutics and lung cancer research. EGFR-mutated adenocarcinoma of the lung has clearly emerged as a unique clinical entity necessitating the routine introduction of molecular diagnostics into our current diagnostic algorithms and leading to the evidence-based preferential usage of EGFR-targeted agents for patients with EGFR-mutant lung cancers. This review will summarize our current understanding of the functional role of activating mutations, key downstream signaling pathways and regulatory mechanisms, pivotal primary and acquired resistance mechanisms, structure-function relationships and ultimately the incorporation of molecular diagnostics and small molecule EGFR tyrosine kinase inhibitors into our current treatment paradigms.
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Affiliation(s)
- Zhenfeng Zhang
- Division of Hematology/Oncology, Herbert Irving Comprehensive Cancer Center, New York Presbyterian Hospital- Columbia University Medical Center, New York, NY, USA
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23
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Chiswell BP, Stiegler AL, Razinia Z, Nalibotski E, Boggon TJ, Calderwood DA. Structural basis of competition between PINCH1 and PINCH2 for binding to the ankyrin repeat domain of integrin-linked kinase. J Struct Biol 2009; 170:157-63. [PMID: 19963065 DOI: 10.1016/j.jsb.2009.12.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2009] [Revised: 11/30/2009] [Accepted: 12/02/2009] [Indexed: 11/16/2022]
Abstract
Formation of a heterotrimeric IPP complex composed of integrin-linked kinase (ILK), the LIM domain protein PINCH, and parvin is important for signaling through integrin adhesion receptors. Mammals possess two PINCH genes that are expressed simultaneously in many tissues. PINCH1 and PINCH2 have overlapping functions and can compensate for one another in many settings; however, isoform-specific functions have been reported and it is proposed that association with a PINCH1- or PINCH2-containing IPP complex may provide a bifurcation point in integrin signaling promoting different cellular responses. Here we report that the LIM1 domains of PINCH1 and PINCH2 directly compete for the same binding site on the ankyrin repeat domain (ARD) of ILK. We determined the 1.9A crystal structure of the PINCH2 LIM1 domain complexed with the ARD of ILK, and show that disruption of this interface by point mutagenesis reduces binding in vitro and alters localization of PINCH2 in cells. These studies provide further evidence for the role of the PINCH LIM1 domain in association with ILK and highlight direct competition as one mechanism for regulating which PINCH isoform predominates in IPP complexes. Differential regulation of PINCH1 and PINCH2 expression may therefore provide a means for altering cellular integrin signaling pathways.
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Affiliation(s)
- Brian P Chiswell
- Department of Pharmacology, 333 Cedar Street, Yale University School of Medicine, New Haven, CT 06520, USA
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24
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Stiegler AL, Burden SJ, Hubbard SR. Crystal structure of the frizzled-like cysteine-rich domain of the receptor tyrosine kinase MuSK. J Mol Biol 2009; 393:1-9. [PMID: 19664639 DOI: 10.1016/j.jmb.2009.07.091] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2009] [Revised: 07/26/2009] [Accepted: 07/30/2009] [Indexed: 12/18/2022]
Abstract
Muscle-specific kinase (MuSK) is an essential receptor tyrosine kinase for the establishment and maintenance of the neuromuscular junction (NMJ). Activation of MuSK by agrin, a neuronally derived heparan-sulfate proteoglycan, and LRP4 (low-density lipoprotein receptor-related protein-4), the agrin receptor, leads to clustering of acetylcholine receptors on the postsynaptic side of the NMJ. The ectodomain of MuSK comprises three immunoglobulin-like domains and a cysteine-rich domain (Fz-CRD) related to those in Frizzled proteins, the receptors for Wnts. Here, we report the crystal structure of the MuSK Fz-CRD at 2.1 A resolution. The structure reveals a five-disulfide-bridged domain similar to CRDs of Frizzled proteins but with a divergent C-terminal region. An asymmetric dimer present in the crystal structure implicates surface hydrophobic residues that may function in homotypic or heterotypic interactions to mediate co-clustering of MuSK, rapsyn, and acetylcholine receptors at the NMJ.
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Affiliation(s)
- Amy L Stiegler
- Structural Biology Program, Kimmel Center for Biology and Medicine of the Skirball Institute, New York University School of Medicine, New York, NY 10016, USA
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25
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Kim N, Stiegler AL, Cameron TO, Hallock PT, Gomez AM, Huang JH, Hubbard SR, Dustin ML, Burden SJ. Lrp4 is a receptor for Agrin and forms a complex with MuSK. Cell 2008; 135:334-42. [PMID: 18848351 DOI: 10.1016/j.cell.2008.10.002] [Citation(s) in RCA: 488] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2008] [Revised: 09/12/2008] [Accepted: 10/01/2008] [Indexed: 12/14/2022]
Abstract
Neuromuscular synapse formation requires a complex exchange of signals between motor neurons and skeletal muscle fibers, leading to the accumulation of postsynaptic proteins, including acetylcholine receptors in the muscle membrane and specialized release sites, or active zones in the presynaptic nerve terminal. MuSK, a receptor tyrosine kinase that is expressed in skeletal muscle, and Agrin, a motor neuron-derived ligand that stimulates MuSK phosphorylation, play critical roles in synaptic differentiation, as synapses do not form in their absence, and mutations in MuSK or downstream effectors are a major cause of a group of neuromuscular disorders, termed congenital myasthenic syndromes (CMS). How Agrin activates MuSK and stimulates synaptic differentiation is not known and remains a fundamental gap in our understanding of signaling at neuromuscular synapses. Here, we report that Lrp4, a member of the LDLR family, is a receptor for Agrin, forms a complex with MuSK, and mediates MuSK activation by Agrin.
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Affiliation(s)
- Natalie Kim
- Molecular Neurobiology Program, Skirball Institute of Biomolecular Medicine, Helen and Martin Kimmel Center for Biology and Medicine, NYU Medical School, New York, NY 10016, USA
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26
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Stiegler AL, Burden SJ, Hubbard SR. Crystal structure of the agrin-responsive immunoglobulin-like domains 1 and 2 of the receptor tyrosine kinase MuSK. J Mol Biol 2006; 364:424-33. [PMID: 17011580 PMCID: PMC1752213 DOI: 10.1016/j.jmb.2006.09.019] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2006] [Revised: 08/30/2006] [Accepted: 09/05/2006] [Indexed: 10/24/2022]
Abstract
Muscle-specific kinase (MuSK) is a receptor tyrosine kinase expressed exclusively in skeletal muscle, where it is required for formation of the neuromuscular junction. MuSK is activated by agrin, a neuron-derived heparan sulfate proteoglycan. Here, we report the crystal structure of the agrin-responsive first and second immunoglobulin-like domains (Ig1 and Ig2) of the MuSK ectodomain at 2.2 A resolution. The structure reveals that MuSK Ig1 and Ig2 are Ig-like domains of the I-set subfamily, which are configured in a linear, semi-rigid arrangement. In addition to the canonical internal disulfide bridge, Ig1 contains a second, solvent-exposed disulfide bridge, which our biochemical data indicate is critical for proper folding of Ig1 and processing of MuSK. Two Ig1-2 molecules form a non-crystallographic dimer that is mediated by a unique hydrophobic patch on the surface of Ig1. Biochemical analyses of MuSK mutants introduced into MuSK(-/-) myotubes demonstrate that residues in this hydrophobic patch are critical for agrin-induced MuSK activation.
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Affiliation(s)
- Amy L Stiegler
- Structural Biology Program, Skirball Institute of Biomolecular Medicine and Department of Pharmacology, New York University School of Medicine, New York, NY 10016, USA
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