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Min CK, Nwachukwu JC, Hou Y, Russo RJ, Papa A, Min J, Peng R, Kim SH, Ziegler Y, Rangarajan ES, Izard T, Katzenellenbogen BS, Katzenellenbogen JA, Nettles KW. Asymmetric Allostery in Estrogen Receptor-α Homodimers Drives Responses to the Ensemble of Estrogens in the Hormonal Milieu. bioRxiv 2024:2024.04.10.588871. [PMID: 38645081 PMCID: PMC11030373 DOI: 10.1101/2024.04.10.588871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
The estrogen receptor-α (ER) is thought to function only as a homodimer, but responds to a variety of environmental, metazoan, and therapeutic estrogens at sub-saturating doses, supporting binding mixtures of ligands as well as dimers that are only partially occupied. Here, we present a series of flexible ER ligands that bind to receptor dimers with individual ligand poses favoring distinct receptor conformations -receptor conformational heterodimers-mimicking the binding of two different ligands. Molecular dynamics simulations showed that the pairs of different ligand poses changed the correlated motion across the dimer interface to generate asymmetric communication between the dimer interface, the ligands, and the surface binding sites for epigenetic regulatory proteins. By examining binding of the same ligand in crystal structures of ER in the agonist versus antagonist conformers, we also showed that these allosteric signals are bidirectional. The receptor conformer can drive different ligand binding modes to support agonist versus antagonist activity profiles, a revision of ligand binding theory that has focused on unidirectional signaling from ligand to the coregulator binding site. We also observed differences in the allosteric signals between ligand and coregulator binding sites in the monomeric versus dimeric receptor, and when bound by two different ligands, states that are physiologically relevant. Thus, ER conformational heterodimers integrate two different ligand-regulated activity profiles, representing new modes for ligand-dependent regulation of ER activity. Significance The estrogen receptor-α (ER) regulates transcription in response to a hormonal milieu that includes low levels of estradiol, a variety of environmental estrogens, as well as ER antagonists such as breast cancer anti-hormonal therapies. While ER has been studied as a homodimer, the variety of ligand and receptor concentrations in different tissues means that the receptor can be occupied with two different ligands, with only one ligand in the dimer, or as a monomer. Here, we use X-ray crystallography and molecular dynamics simulations to reveal a new mode for ligand regulation of ER activity whereby sequence-identical homodimers can act as functional or conformational heterodimers having unique signaling characteristics, with ligand-selective allostery operating across the dimer interface integrating two different signaling outcomes.
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Gupta J, Rangarajan ES, Troyanovsky RB, Indra I, Troyanovsky SM, Izard T. Plakophilin-3 Binds the Membrane and Filamentous Actin without Bundling F-Actin. Int J Mol Sci 2023; 24:9458. [PMID: 37298410 PMCID: PMC10253835 DOI: 10.3390/ijms24119458] [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: 04/28/2023] [Revised: 05/21/2023] [Accepted: 05/26/2023] [Indexed: 06/12/2023] Open
Abstract
Plakophilin-3 is a ubiquitously expressed protein found widely in epithelial cells and is a critical component of desmosomes. The plakophilin-3 carboxy-terminal domain harbors nine armadillo repeat motifs with largely unknown functions. Here, we report the 5 Å cryogenic electron microscopy (cryoEM) structure of the armadillo repeat motif domain of plakophilin-3, one of the smaller cryoEM structures reported to date. We find that this domain is a monomer or homodimer in solution. In addition, using an in vitro actin co-sedimentation assay, we show that the armadillo repeat domain of plakophilin-3 directly interacts with F-actin. This feature, through direct interactions with actin filaments, could be responsible for the observed association of extra-desmosomal plakophilin-3 with the actin cytoskeleton directly attached to the adherens junctions in A431 epithelial cells. Further, we demonstrate, through lipid binding analyses, that plakophilin-3 can effectively be recruited to the plasma membrane through phosphatidylinositol-4,5-bisphosphate-mediated interactions. Collectively, we report on novel properties of plakophilin-3, which may be conserved throughout the plakophilin protein family and may be behind the roles of these proteins in cell-cell adhesion.
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Affiliation(s)
- Jyoti Gupta
- Cell Adhesion Laboratory, UF Scripps, Jupiter, FL 33458, USA
| | | | - Regina B. Troyanovsky
- Department of Dermatology, The Feinberg School of Medicine, Northwestern University, Chicago, IL 606112, USA
| | - Indrajyoti Indra
- Department of Dermatology, The Feinberg School of Medicine, Northwestern University, Chicago, IL 606112, USA
| | - Sergey M. Troyanovsky
- Department of Dermatology, The Feinberg School of Medicine, Northwestern University, Chicago, IL 606112, USA
| | - Tina Izard
- Cell Adhesion Laboratory, UF Scripps, Jupiter, FL 33458, USA
- The Skaggs Graduate School, The Scripps Research Institute, La Jolla, CA 92037, USA
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Rangarajan ES, Smith EW, Izard T. Distinct inter-domain interactions of dimeric versus monomeric α-catenin link cell junctions to filaments. Commun Biol 2023; 6:276. [PMID: 36928388 PMCID: PMC10020564 DOI: 10.1038/s42003-023-04610-x] [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: 09/02/2022] [Accepted: 02/17/2023] [Indexed: 03/18/2023] Open
Abstract
Attachment between cells is crucial for almost all aspects of the life of cells. These inter-cell adhesions are mediated by the binding of transmembrane cadherin receptors of one cell to cadherins of a neighboring cell. Inside the cell, cadherin binds β-catenin, which interacts with α-catenin. The transitioning of cells between migration and adhesion is modulated by α-catenin, which links cell junctions and the plasma membrane to the actin cytoskeleton. At cell junctions, a single β-catenin/α-catenin heterodimer slips along filamentous actin in the direction of cytoskeletal tension which unfolds clustered heterodimers to form catch bonds with F-actin. Outside cell junctions, α-catenin dimerizes and links the plasma membrane to F-actin. Under cytoskeletal tension, α-catenin unfolds and forms an asymmetric catch bond with F-actin. To understand the mechanism of this important α-catenin function, we determined the 2.7 Å cryogenic electron microscopy (cryoEM) structures of filamentous actin alone and bound to human dimeric α-catenin. Our structures provide mechanistic insights into the role of the α-catenin interdomain interactions in directing α-catenin function and suggest a bivalent mechanism. Further, our cryoEM structure of human monomeric α-catenin provides mechanistic insights into α-catenin autoinhibition. Collectively, our structures capture the initial α-catenin interaction with F-actin before the sensing of force, which is a crucial event in cell adhesion and human disease.
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Affiliation(s)
| | - Emmanuel W Smith
- The Cell Adhesion Laboratory, UF Scripps, Jupiter, FL, 33458, USA
| | - Tina Izard
- The Cell Adhesion Laboratory, UF Scripps, Jupiter, FL, 33458, USA.
- The Skaggs Graduate School, The Scripps Research Institute, Jupiter, FL, 33458, USA.
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Rangarajan ES, Smith EW, Izard T. The nematode α-catenin ortholog, HMP1, has an extended α-helix when bound to actin filaments. J Biol Chem 2023; 299:102817. [PMID: 36539037 PMCID: PMC9860117 DOI: 10.1016/j.jbc.2022.102817] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 12/09/2022] [Accepted: 12/11/2022] [Indexed: 12/23/2022] Open
Abstract
The regulation of cell-cell junctions during epidermal morphogenesis ensures tissue integrity, a process regulated by α-catenin. This cytoskeletal protein connects the cadherin complex to filamentous actin at cell-cell junctions. The cadherin-catenin complex plays key roles in cell physiology, organism development, and disease. While mutagenesis of Caenorhabditis elegans cadherin and catenin shows that these proteins are key for embryonic morphogenesis, we know surprisingly little about their structure and attachment to the cytoskeleton. In contrast to mammalian α-catenin that functions as a dimer or monomer, the α-catenin ortholog from C. elegans, HMP1 for humpback, is a monomer. Our cryogenic electron microscopy (cryoEM) structure of HMP1/α-catenin reveals that the amino- and carboxy-terminal domains of HMP1/α-catenin are disordered and not in contact with the remaining HMP1/α-catenin middle domain. Since the carboxy-terminal HMP1/α-catenin domain is the F-actin-binding domain (FABD), this interdomain constellation suggests that HMP1/α-catenin is constitutively active, which we confirm biochemically. Our perhaps most surprising finding, given the high sequence similarity between the mammalian and nematode proteins, is our cryoEM structure of HMP1/α-catenin bound to F-actin. Unlike the structure of mammalian α-catenin bound to F-actin, binding to F-actin seems to allosterically convert a loop region of the HMP1/α-catenin FABD to extend an HMP1/α-catenin FABD α-helix. We use cryoEM and bundling assays to show for the first time how the FABD of HMP1/α-catenin bundles actin in the absence of force. Collectively, our data advance our understanding of α-catenin regulation of cell-cell contacts and additionally aid our understanding of the evolution of multicellularity in metazoans.
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Affiliation(s)
| | | | - Tina Izard
- Cell Adhesion Laboratory, UF Scripps, Jupiter, Florida, USA; The Skaggs Graduate School, The Scripps Research Institute, Jupiter, Florida, USA.
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Tinivella A, Nwachukwu JC, Angeli A, Foschi F, Benatti AL, Pinzi L, Izard T, Ferraroni M, Erumbi R, Christodoulou MS, Passarella D, Supuran CT, Nettles KW, Rastelli G. Design, synthesis, biological evaluation and crystal structure determination of dual modulators of carbonic anhydrases and estrogen receptors. Eur J Med Chem 2023; 246:115011. [PMID: 36516582 DOI: 10.1016/j.ejmech.2022.115011] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Revised: 11/28/2022] [Accepted: 12/05/2022] [Indexed: 12/13/2022]
Abstract
Multi-target compounds have become increasingly important for the development of safer and more effective drug candidates. In this work, we devised a combined ligand-based and structure-based multi-target repurposing strategy and applied it to a series of hexahydrocyclopenta[c]quinoline compounds synthesized previously. The in silico analyses identified human Carbonic Anhydrases (hCA) and Estrogen Receptors (ER) as top scoring candidates for dual modulation. hCA isoforms IX and XII, and ER subtypes ER⍺ and/or ERβ are co-expressed in various cancer cell types, including breast and prostate cancer cells. ER⍺ is the primary target of anti-estrogen therapy in breast cancer, and the hCA IX isoform is a therapeutic target in triple-negative breast cancer. ER⍺-mediated transcriptional programs and hCA activity in cancer cells promote favorable microenvironments for cell proliferation. Interestingly, several lines of evidence indicate that the combined modulation of these two targets may provide significant therapeutic benefits. Moving from these first results, two additional hexahydrocyclopenta[c]quinoline derivatives bearing a sulfonamide zinc binding group (hCA) and a phenolic hydroxyl (ER) pharmacophoric group placed at the appropriate locations were designed and synthesized. Interestingly, these compounds were able to directly modulate the activities of both hCA and ER targets. In cell-based assays, they inhibited proliferation of breast and prostate cancer cells with micromolar potency and cell type-selective efficacy. The compounds inhibited hCA activity with nanomolar potency and isoform-selectivity. In transactivation assays, they reduced estrogen-driven ER activity with micro-molar potency. Finally, crystal structures of the synthesized ligands in complex with the two targets revealed that the compounds bind directly to the hCA active site, as well as to the ER ligand-binding domain, providing structural explanation to the observed activity and a rationale for optimization of their dual activity. To the best of our knowledge, this work describes the design, synthesis and biological characterization of the first dual modulators of hCA and ER, laying the ground for the structure-based optimization of their multi-target activity.
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Affiliation(s)
- Annachiara Tinivella
- Department of Life Sciences, University of Modena and Reggio Emilia, Via Giuseppe Campi 103, 41125, Modena, Italy; Clinical and Experimental Medicine PhD Program, University of Modena and Reggio Emilia, Modena, Italy
| | - Jerome C Nwachukwu
- Department of Integrative Structural and Computational Biology, University of Florida Scripps Biomedical Research, 130 Scripps Way, Jupiter, FL, 33458, USA
| | - Andrea Angeli
- NEUROFARBA Department, Sezione di Scienze Farmaceutiche, University of Florence, Via Ugo Schiff 6, 50019, Sesto Fiorentino, Florence, Italy
| | - Francesca Foschi
- Department of Life Sciences, University of Modena and Reggio Emilia, Via Giuseppe Campi 103, 41125, Modena, Italy; Department of Chemistry, University of Milano, Via Golgi 19, 20133, Milano, Italy
| | - Anna Laura Benatti
- Department of Life Sciences, University of Modena and Reggio Emilia, Via Giuseppe Campi 103, 41125, Modena, Italy
| | - Luca Pinzi
- Department of Life Sciences, University of Modena and Reggio Emilia, Via Giuseppe Campi 103, 41125, Modena, Italy
| | - Tina Izard
- Department of Integrative Structural and Computational Biology, University of Florida Scripps Biomedical Research, 130 Scripps Way, Jupiter, FL, 33458, USA
| | - Marta Ferraroni
- Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 13, 50019, Sesto Fiorentino, Florence, Italy
| | - Rangarajan Erumbi
- Department of Integrative Structural and Computational Biology, University of Florida Scripps Biomedical Research, 130 Scripps Way, Jupiter, FL, 33458, USA
| | - Michael S Christodoulou
- Department of Life Sciences, University of Modena and Reggio Emilia, Via Giuseppe Campi 103, 41125, Modena, Italy; Department of Chemistry, University of Milano, Via Golgi 19, 20133, Milano, Italy
| | - Daniele Passarella
- Department of Chemistry, University of Milano, Via Golgi 19, 20133, Milano, Italy
| | - Claudiu T Supuran
- NEUROFARBA Department, Sezione di Scienze Farmaceutiche, University of Florence, Via Ugo Schiff 6, 50019, Sesto Fiorentino, Florence, Italy
| | - Kendall W Nettles
- Department of Integrative Structural and Computational Biology, University of Florida Scripps Biomedical Research, 130 Scripps Way, Jupiter, FL, 33458, USA
| | - Giulio Rastelli
- Department of Life Sciences, University of Modena and Reggio Emilia, Via Giuseppe Campi 103, 41125, Modena, Italy.
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Patil DN, Singh S, Laboute T, Strutzenberg T, Qiu X, Wu D, Novick S, Robinson C, Griffin P, Hunt J, Izard T, Singh A, Martemyanov K. Visualizing an orphan receptor GPR158 and it complex with neuronal regulator RGS7‐Gβ5 via cryoEM. FASEB J 2022. [DOI: 10.1096/fasebj.2022.36.s1.r6204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Shikha Singh
- Department of Biological SciencesColumbia University New YorkNew yorkNY
| | | | | | | | - Di Wu
- University of OxfordOxford
| | | | | | | | - John Hunt
- Columbia University New YorkNew YorkNY
| | | | - Appu Singh
- Indian Institute of Technology KanpurKanpur
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Patil DN, Singh S, Laboute T, Strutzenberg TS, Qiu X, Wu D, Novick SJ, Robinson CV, Griffin PR, Hunt JF, Izard T, Singh AK, Martemyanov KA. Cryo-EM structure of human GPR158 receptor coupled to the RGS7-Gβ5 signaling complex. Science 2022; 375:86-91. [PMID: 34793198 PMCID: PMC8926151 DOI: 10.1126/science.abl4732] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
GPR158 is an orphan G protein–coupled receptor (GPCR) highly expressed in the brain, where it controls synapse formation and function. GPR158 has also been implicated in depression, carcinogenesis, and cognition. However, the structural organization and signaling mechanisms of GPR158 are largely unknown. We used single-particle cryo–electron microscopy (cryo-EM) to determine the structures of human GPR158 alone and bound to an RGS signaling complex. The structures reveal a homodimeric organization stabilized by a pair of phospholipids and the presence of an extracellular Cache domain, an unusual ligand-binding domain in GPCRs. We further demonstrate the structural basis of GPR158 coupling to RGS7-Gβ5. Together, these results provide insights into the unusual biology of orphan receptors and the formation of GPCR-RGS complexes.
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Affiliation(s)
- Dipak N. Patil
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Shikha Singh
- Department of Biological Sciences, Columbia University New York, NY 10027
| | - Thibaut Laboute
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | | | - Xingyu Qiu
- Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K.,The Kavli Institute for Nanoscience Discovery, Oxford, OX1 3QU, UK
| | - Di Wu
- Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K.,The Kavli Institute for Nanoscience Discovery, Oxford, OX1 3QU, UK
| | - Scott J. Novick
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Carol V. Robinson
- Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K.,The Kavli Institute for Nanoscience Discovery, Oxford, OX1 3QU, UK
| | - Patrick R. Griffin
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - John F. Hunt
- Department of Biological Sciences, Columbia University New York, NY 10027
| | - Tina Izard
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Appu K. Singh
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India,Mehta Family Centre for Engineering in Medicine, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016, India,Co-corresponding authors: Dr. Kirill A. Martemyanov, ; Dr. Appu K. Singh,
| | - Kirill A. Martemyanov
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA,Co-corresponding authors: Dr. Kirill A. Martemyanov, ; Dr. Appu K. Singh,
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Primi MC, Tavares MT, Klein LL, Izard T, Sant'Anna CMR, Franzblau SG, Ferreira EI. Design of Novel Phosphopantetheine Adenylyltransferase Inhibitors: a Potential New Approach to Tackle Mycobacterium tuberculosis. Curr Top Med Chem 2021; 21:1186-1197. [PMID: 34323186 DOI: 10.2174/1568026621666210728094804] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 06/23/2021] [Accepted: 07/02/2021] [Indexed: 11/22/2022]
Abstract
BACKGROUND Tuberculosis (TB) has been a challenging disease worldwide, especially for the neglected poor populations. Presently, there are approximately 2 billion people infected with TB worldwide and 10 million people in the world fell ill with active TB, leading to 1.5 million deaths. INTRODUCTION The classic treatment is extensive and the drug and multi drug resistance of Mycobacterium tuberculosis has been a threat to the efficacy of the drugs currently used. Therefore, the rational design of new anti TB candidates is urgently needed. METHODS With the aim of contributing to face this challenge, 78 compounds have been proposed based on SBDD (Structure Based Drug Design) strategies applied to target the M. tuberculosis phosphopantetheine adenylyltransferase (MtPPAT) enzyme. Ligand Based Drug Design (LBDD) strategies were also used for establishing structure activity relationships (SAR) and for optimizing the structures. MtPPAT is important for the biosynthesis of coenzyme A (CoA) and it has been studied recently toward the discovery of new inhibitors. RESULTS After docking simulations and enthalpy calculations, the interaction of selected compounds with MtPPAT was found to be energetically favorable. The most promising compounds were then synthesized and submitted to anti M. tuberculosis and MtPPAT inhibition assays. CONCLUSION One of the compounds synthesized (MCP163), showed the highest activity in both of these assays.
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Affiliation(s)
- Marina C Primi
- Department of Pharmacy, Faculty of Pharmaceutical Sciences, University of Sao Paulo, Sao Paulo. Brazil
| | - Maurício T Tavares
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, United States
| | - Larry L Klein
- Institute for Tuberculosis Research, College of Pharmacy, University of Illinois at Chicago, Chicago, United States
| | - Tina Izard
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, Jupiter, United States
| | - Carlos M R Sant'Anna
- Department of Fundamental Chemistry, Institute of Chemistry, Federal Rural University of Rio de Janeiro, Seropedica. Brazil
| | - Scott G Franzblau
- Institute for Tuberculosis Research, College of Pharmacy, University of Illinois at Chicago, Chicago, United States
| | - Elizabeth I Ferreira
- Department of Pharmacy, Faculty of Pharmaceutical Sciences, University of Sao Paulo, Sao Paulo. Brazil
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Primi MC, Rangarajan ES, Patil DN, Izard T. Conformational flexibility determines the Nf2/merlin tumor suppressor functions. Matrix Biol Plus 2021; 12:100074. [PMID: 34337379 PMCID: PMC8318988 DOI: 10.1016/j.mbplus.2021.100074] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 06/14/2021] [Accepted: 06/15/2021] [Indexed: 10/26/2022] Open
Abstract
The Neurofibromatosis type 2 gene encodes the Nf2/merlin tumor suppressor protein that is responsible for the regulation of cell proliferation. Once activated, Nf2/merlin modulates adhesive signaling pathways and thereby inhibits cell growth. Nf2/merlin controls oncogenic gene expression by modulating the Hippo pathway. By responding to several physical and biochemical stimuli, Hippo signaling determines contact inhibition of proliferation as well as organ size. The large tumor suppressor (LATS) serine/threonine-protein kinase is the key enzyme in the highly conserved kinase cascade that negatively regulates the activity and localization of the transcriptional coactivators Yes-associated protein (YAP) and its paralogue transcriptional coactivator with PDZ-binding motif (TAZ). Nf2/merlin belongs to the band 4.1, ezrin, radixin, moesin (FERM) gene family that links the actin cytoskeleton to adherens junctions, remodels adherens junctions during epithelial morphogenesis and maintains organized apical surfaces on the plasma cell membrane. Nf2/merlin and ERM proteins have a globular N-terminal cloverleaf head domain, the FERM domain, that binds to the plasma membrane, a central α-helical domain, and a tail domain that binds to its head domain. Here we present the high-resolution crystal structure of Nf2/merlin bound to LATS1 which shows that LATS1 binding to Nf2/merlin displaces the Nf2/merlin tail domain and causes an allosteric shift in the Nf2/merlin α-helix that extends from its FERM domain. This is consistent with the fact that full-length Nf2/merlin binds LATS1 ~10-fold weaker compared to LATS1 binding to the Nf2/merlin-PIP2 complex. Our data increase our understanding of Nf2/merlin biology by providing mechanistic insights into the Hippo pathway that are relevant to several diseases in particular oncogenic features that are associated with cancers.
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Affiliation(s)
- Marina C Primi
- Cell Adhesion Laboratory, Department of Integrative Structural and Computational Biology, The Scripps Research Institute, Jupiter 33458, FL, United States
| | - Erumbi S Rangarajan
- Cell Adhesion Laboratory, Department of Integrative Structural and Computational Biology, The Scripps Research Institute, Jupiter 33458, FL, United States
| | - Dipak N Patil
- Cell Adhesion Laboratory, Department of Integrative Structural and Computational Biology, The Scripps Research Institute, Jupiter 33458, FL, United States
| | - Tina Izard
- Cell Adhesion Laboratory, Department of Integrative Structural and Computational Biology, The Scripps Research Institute, Jupiter 33458, FL, United States
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10
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Rangarajan ES, Izard T. The Cryogenic Electron Microscopy Structure of the Cell Adhesion Regulator Metavinculin Reveals an Isoform-Specific Kinked Helix in Its Cytoskeleton Binding Domain. Int J Mol Sci 2021; 22:E645. [PMID: 33440717 PMCID: PMC7827843 DOI: 10.3390/ijms22020645] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 01/08/2021] [Accepted: 01/08/2021] [Indexed: 11/16/2022] Open
Abstract
Vinculin and its heart-specific splice variant metavinculin are key regulators of cell adhesion processes. These membrane-bound cytoskeletal proteins regulate the cell shape by binding to several other proteins at cell-cell and cell-matrix junctions. Vinculin and metavinculin link integrin adhesion molecules to the filamentous actin network. Loss of both proteins prevents cell adhesion and cell spreading and reduces the formation of stress fibers, focal adhesions, or lamellipodia extensions. The binding of talin at cell-matrix junctions or of α-catenin at cell-cell junctions activates vinculin and metavinculin by releasing their autoinhibitory head-tail interaction. Once activated, vinculin and metavinculin bind F-actin via their five-helix bundle tail domains. Unlike vinculin, metavinculin has a 68-amino-acid insertion before the second α-helix of this five-helix F-actin-binding domain. Here, we present the full-length cryogenic electron microscopy structure of metavinculin that captures the dynamics of its individual domains and unveiled a hallmark structural feature, namely a kinked isoform-specific α-helix in its F-actin-binding domain. Our identified conformational landscape of metavinculin suggests a structural priming mechanism that is consistent with the cell adhesion functions of metavinculin in response to mechanical and cellular cues. Our findings expand our understanding of metavinculin function in the heart with implications for the etiologies of cardiomyopathies.
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Affiliation(s)
| | - Tina Izard
- Cell Adhesion Laboratory, Department of Integrative Structural and Computational Biology, The Scripps Research Institute, Jupiter, FL 33458, USA;
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11
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Zhang L, Jackson CB, Mou H, Ojha A, Peng H, Quinlan BD, Rangarajan ES, Pan A, Vanderheiden A, Suthar MS, Li W, Izard T, Rader C, Farzan M, Choe H. SARS-CoV-2 spike-protein D614G mutation increases virion spike density and infectivity. Nat Commun 2020; 11:6013. [PMID: 33243994 PMCID: PMC7693302 DOI: 10.1038/s41467-020-19808-4] [Citation(s) in RCA: 620] [Impact Index Per Article: 155.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 10/27/2020] [Indexed: 12/17/2022] Open
Abstract
SARS-CoV-2 variants with spike (S)-protein D614G mutations now predominate globally. We therefore compare the properties of the mutated S protein (SG614) with the original (SD614). We report here pseudoviruses carrying SG614 enter ACE2-expressing cells more efficiently than those with SD614. This increased entry correlates with less S1-domain shedding and higher S-protein incorporation into the virion. Similar results are obtained with virus-like particles produced with SARS-CoV-2 M, N, E, and S proteins. However, D614G does not alter S-protein binding to ACE2 or neutralization sensitivity of pseudoviruses. Thus, D614G may increase infectivity by assembling more functional S protein into the virion.
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Affiliation(s)
- Lizhou Zhang
- Department of Immunology and Microbiology, The Scripps Research Institute, Jupiter, FL, USA
| | - Cody B Jackson
- Department of Immunology and Microbiology, The Scripps Research Institute, Jupiter, FL, USA
| | - Huihui Mou
- Department of Immunology and Microbiology, The Scripps Research Institute, Jupiter, FL, USA
| | - Amrita Ojha
- Department of Immunology and Microbiology, The Scripps Research Institute, Jupiter, FL, USA
| | - Haiyong Peng
- Department of Immunology and Microbiology, The Scripps Research Institute, Jupiter, FL, USA
| | - Brian D Quinlan
- Department of Immunology and Microbiology, The Scripps Research Institute, Jupiter, FL, USA
| | - Erumbi S Rangarajan
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, Jupiter, FL, USA
| | - Andi Pan
- Department of Immunology and Microbiology, The Scripps Research Institute, Jupiter, FL, USA
| | - Abigail Vanderheiden
- Department of Pediatrics, Division of Infectious Disease, Emory University School of Medicine, Atlanta, GA, USA
- Emory Vaccine Center, Emory University School of Medicine, Atlanta, GA, USA
- Yerkes National Primate Research Center, Atlanta, GA, USA
- Emory-UGA Center of Excellence of Influenza Research and Surveillance (CEIRS), Atlanta, GA, USA
| | - Mehul S Suthar
- Department of Pediatrics, Division of Infectious Disease, Emory University School of Medicine, Atlanta, GA, USA
- Emory Vaccine Center, Emory University School of Medicine, Atlanta, GA, USA
- Yerkes National Primate Research Center, Atlanta, GA, USA
- Emory-UGA Center of Excellence of Influenza Research and Surveillance (CEIRS), Atlanta, GA, USA
| | - Wenhui Li
- National Institute of Biological Sciences, Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, China
| | - Tina Izard
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, Jupiter, FL, USA
| | - Christoph Rader
- Department of Immunology and Microbiology, The Scripps Research Institute, Jupiter, FL, USA
| | - Michael Farzan
- Department of Immunology and Microbiology, The Scripps Research Institute, Jupiter, FL, USA.
| | - Hyeryun Choe
- Department of Immunology and Microbiology, The Scripps Research Institute, Jupiter, FL, USA.
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12
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Abstract
The composition and organization of the plasma membrane play important functional and regulatory roles in integrin signaling, which direct many physiological and pathological processes, such as development, wound healing, immunity, thrombosis, and cancer metastasis. Membranes are comprised of regions that are thick or thin owing to spontaneous partitioning of long-chain saturated lipids from short-chain polyunsaturated lipids into domains defined as ordered and liquid-disorder domains, respectively. Liquid-ordered domains are typically 100 nm in diameter and sometimes referred to as lipid rafts. We posit that integrin β senses membrane thickness and that mechanical force on the membrane regulates integrin activation through membrane thinning. This review examines what we know about the nature and mechanism of the interaction of integrins with the plasma membrane and its effects on regulating integrins and its binding partners.
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Affiliation(s)
- Daniel Lietha
- Cell Signaling and Adhesion Group, Structural and Chemical Biology, Margarita Salas Center for Biological Research (CIB-CSIC), E-28040 Madrid, Spain;
| | - Tina Izard
- Cell Adhesion Laboratory, Department of Integrative Structural and Computational Biology, The Scripps Research Institute, Jupiter, FL 33458, USA
- Correspondence:
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13
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Rangarajan ES, Primi MC, Colgan LA, Chinthalapudi K, Yasuda R, Izard T. A distinct talin2 structure directs isoform specificity in cell adhesion. J Biol Chem 2020; 295:12885-12899. [PMID: 32605925 DOI: 10.1074/jbc.ra119.010789] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 06/23/2020] [Indexed: 01/25/2023] Open
Abstract
Integrin receptors regulate normal cellular processes such as signaling, cell migration, adhesion to the extracellular matrix, and leukocyte function. Talin recruitment to the membrane is necessary for its binding to and activation of integrin. Vertebrates have two highly conserved talin homologs that differ in their expression patterns. The F1-F3 FERM subdomains of cytoskeletal proteins resemble a cloverleaf, but in talin1, its F1 subdomain and additional F0 subdomain align more linearly with its F2 and F3 subdomains. Here, we present the talin2 crystal structure, revealing that its F0-F1 di-subdomain displays another unprecedented constellation, whereby the F0-F1-F2 adopts a new cloverleaf-like arrangement. Using multiangle light scattering (MALS), fluorescence lifetime imaging (FLIM), and FRET analyses, we found that substituting the corresponding residues in talin2 that abolish lipid binding in talin1 disrupt the binding of talin to the membrane, focal adhesion formation, and cell spreading. Our results provide the molecular details of the functions of specific talin isoforms in cell adhesion.
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Affiliation(s)
- Erumbi S Rangarajan
- Cell Adhesion Laboratory, Department of Integrative Structural and Computational Biology, The Scripps Research Institute, Jupiter, Florida, USA
| | - Marina C Primi
- Cell Adhesion Laboratory, Department of Integrative Structural and Computational Biology, The Scripps Research Institute, Jupiter, Florida, USA
| | - Lesley A Colgan
- Neuronal Signal Transduction, Max Planck Florida Institute for Neuroscience, Jupiter, Florida, USA
| | - Krishna Chinthalapudi
- Cell Adhesion Laboratory, Department of Integrative Structural and Computational Biology, The Scripps Research Institute, Jupiter, Florida, USA
| | - Ryohei Yasuda
- Neuronal Signal Transduction, Max Planck Florida Institute for Neuroscience, Jupiter, Florida, USA
| | - Tina Izard
- Cell Adhesion Laboratory, Department of Integrative Structural and Computational Biology, The Scripps Research Institute, Jupiter, Florida, USA.
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14
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Zhang L, Jackson CB, Mou H, Ojha A, Rangarajan ES, Izard T, Farzan M, Choe H. The D614G mutation in the SARS-CoV-2 spike protein reduces S1 shedding and increases infectivity. bioRxiv 2020:2020.06.12.148726. [PMID: 32587973 PMCID: PMC7310631 DOI: 10.1101/2020.06.12.148726] [Citation(s) in RCA: 312] [Impact Index Per Article: 78.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
SARS coronavirus 2 (SARS-CoV-2) isolates encoding a D614G mutation in the viral spike (S) protein predominate over time in locales where it is found, implying that this change enhances viral transmission. We therefore compared the functional properties of the S proteins with aspartic acid (S D614 ) and glycine (S G614 ) at residue 614. We observed that retroviruses pseudotyped with S G614 infected ACE2-expressing cells markedly more efficiently than those with S D614 . This greater infectivity was correlated with less S1 shedding and greater incorporation of the S protein into the pseudovirion. Similar results were obtained using the virus-like particles produced with SARS-CoV-2 M, N, E, and S proteins. However, S G614 did not bind ACE2 more efficiently than S D614 , and the pseudoviruses containing these S proteins were neutralized with comparable efficiencies by convalescent plasma. These results show S G614 is more stable than S D614 , consistent with epidemiological data suggesting that viruses with S G614 transmit more efficiently.
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Affiliation(s)
- Lizhou Zhang
- Department of Immunology and Microbial Science, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Cody B Jackson
- Department of Immunology and Microbial Science, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Huihui Mou
- Department of Immunology and Microbial Science, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Amrita Ojha
- Department of Immunology and Microbial Science, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Erumbi S Rangarajan
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, Jupiter, Florida 33458
| | - Tina Izard
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, Jupiter, Florida 33458
| | - Michael Farzan
- Department of Immunology and Microbial Science, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Hyeryun Choe
- Department of Immunology and Microbial Science, The Scripps Research Institute, Jupiter, FL 33458, USA
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15
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Nwachukwu J, Min J, Srinivasan SK, Rangarajan E, Guillen VS, Ziegler Y, Carlson K, Hou Y, Kim SH, Izard T, Houtman R, Katzenellenbogen BS, Nettles KW, Katzenellenbogen JA. OR12-07 Full Antagonism of Breast Cancer Cell Proliferation Can Result from Many Ligand-Induced Conformational Distortions of the Estrogen Receptor Ligand Binding Domain. J Endocr Soc 2020. [PMCID: PMC7209757 DOI: 10.1210/jendso/bvaa046.249] [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] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Although most estrogen receptor alpha (ERα)-positive breast cancers initially respond well to endocrine therapies using aromatase inhibitors (AIs) or antiestrogens, after varying time periods the cancer frequently recurs as metastatic disease. A significant fraction of these recurrences are driven by ERs that have acquired activating mutations in their ligand binding domains (LBDs), giving them constitutive activity and thus resistance to AIs. Because these mutations also reduce the affinity and potency of SERMs and SERDs, expanded efforts have been made to vary the structure of antiestrogens to make them more potent. Typical antiestrogens are comprised of a core element that binds securely in the ligand binding pocket and from which extends a single ring (ring E) having a side chain that sterically interferes with the position of helix-12 by direct antagonism, reorienting it so that it occludes the activation function 2 (AF2) hydrophobic groove for coactivator binding. Through structural studies, we found that bridged oxabicycloheptene-sulfonamide (OBHS-N) core ligands have two rings (E and F) that can be poised to engage in both “direct antagonism” and “indirect antagonism”, the latter of which disrupts the orientation of helix-12 by impinging on helix-11 and the helix-11–12 loop. In this study, we have placed typical antiestrogen side chains on either the E or the F ring of OBHS-N core ligands and characterized their activities in ERα-positive breast cancer cells. All compounds have full antiproliferative activity and reverse estrogen-regulated gene expression, with the antiproliferative potency of each type of side chain having a distinct preference for E- vs F-ring attachment. Conformational analysis using a multiplexed coregulator peptide interaction assay shows that compounds with an E-ring substitution have interaction profiles similar to 4-hydroxytamoxifen and fulvestrant, whereas the F-ring substitution gives a very different pattern, suggesting that the antagonist activity of the two classes rely on different sets of coregulator proteins. A large number of high resolution (better than 2 Å) X-ray crystal structures reveal that this set of novel ER antagonists disrupt the conformation of the ER LBD in a variety of ways, several of which are distinct from those seen with previous antiestrogens such as Tamoxifen and Fulvestrant. Our findings expand design concepts by which ERα ligands can block the activity of this receptor and illustrate how direct and indirect modes of ER antagonism can be combined to facilitate the development of more efficacious antiestrogens for breast cancer treatment and possibly for regulating ER-mediated activities in other estrogen target tissues.
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Affiliation(s)
| | | | | | | | | | - Yvonne Ziegler
- University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | | | - Yingwei Hou
- University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Sung Hoon Kim
- University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Tina Izard
- The Scripps Research Institute, Jupiter, FL, USA
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16
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Cao W, Kayama H, Chen ML, Delmas A, Sun A, Kim SY, Rangarajan ES, McKevitt K, Beck AP, Jackson CB, Crynen G, Oikonomopoulos A, Lacey PN, Martinez GJ, Izard T, Lorenz RG, Rodriguez-Palacios A, Cominelli F, Abreu MT, Hommes DW, Koralov SB, Takeda K, Sundrud MS. The Xenobiotic Transporter Mdr1 Enforces T Cell Homeostasis in the Presence of Intestinal Bile Acids. Immunity 2020; 52:571. [PMID: 32187521 DOI: 10.1016/j.immuni.2020.01.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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17
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Katzenellenbogen JA, Min J, Srinivasan S, Rangarajan ES, Nwachukwu JC, Guillen VS, Ziegler Y, Yan S, Carlson KE, Hou Y, Kim SH, Izard T, Houtman R, Nettles KW, Katzenellenbogen BS. Abstract P6-04-10: Combining direct and indirect modes of antiestrogen ligand antagonism of estrogen receptor activity in breast cancer. Cancer Res 2020. [DOI: 10.1158/1538-7445.sabcs19-p6-04-10] [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] [Indexed: 11/16/2022]
Abstract
Abstract
Resistance to endocrine therapies in breast cancer highlights the need to explore new modes for antagonizing the activity of estrogen receptor alpha (ERα) that might lead to clinically more effective antiestrogens. Most clinically approved antiestrogens, however, have conceptually similar overall structures. Typically, this includes a lipophilic ligand core with a single side chain attached to an E-ring that uses direct steric contact to displace helix-12 of the ER ligand binding domain (LBD) from the agonist conformation. Unlike conventional antiestrogens, certain structurally bridged oxabicycloheptene-sulfonamide (OBHS-N) ER ligands have two rings (E and F) onto which side chains can be attached, thereby probing two distinct regions and modes of antagonism within the ER LBD. We attached characteristic ER antagonist side chains onto each of these two rings seeking to displace helix-12 sterically (“direct antagonism”) and/or to distort the ligand binding pocket and thereby alter the conformation of the helix-11/12 loop (a distinct mode, termed “indirect antagonism”). Several of these OBHS-N compounds have full antiproliferative activity on ERα-positive breast cancer cells and reverse estrogen-regulated gene expression, and the inhibitory potency of compounds with each type of side chain shows a distinct preference for E- or F-ring of attachment. Conformational analysis of these ER-ligand complexes using a multiplexed coregulator peptide interaction assay shows that sidechain substitution on the E-ring gives interaction profiles similar to that for hydroxytamoxifen and fulvestrant, whereas F-ring substitution gives a very different pattern. X-ray crystallographic structure analysis confirms that F-ring substituted OBHS-N compounds use a combination of direct and indirect modes of antagonism that both displaces and disorders helix-12 of the ER LBD. Our findings expand design concepts by which ERα ligands can block the activity of this receptor in breast cancers and structurally how direct and indirect modes of inhibition can be combined. This could facilitate the development of more efficacious antiestrogens for breast cancer treatment. Supported by the Breast Cancer Research Foundation (BCRF 18-084 to JAK and BSK) and the National Institutes of Health (R01 CA220284 to JAK, BSK, TI, and KWN; T32 GM070421 Fellowship to VSG).
Citation Format: John A Katzenellenbogen, Jian Min, Sathish Srinivasan, Erumbi S. Rangarajan, Jerome C. Nwachukwu, Valeria Sanabria Guillen, Yvonne Ziegler, Shunchao Yan, Kathryn E. Carlson, Yingwei Hou, Sung Hoon Kim, Tina Izard, Rene Houtman, Kendall W. Nettles, Benita S. Katzenellenbogen. Combining direct and indirect modes of antiestrogen ligand antagonism of estrogen receptor activity in breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P6-04-10.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | - Tina Izard
- 3The Scripps Research Institute, Jupiter, FL
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18
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Abstract
Homeostasis in healthy tissues strongly relies on cell-to-cell adhesion and cell-to-extracellular matrix interactions. For instance, normal epithelial cells maintain tissue structure by adhering to each other and to the extracellular matrix. The proteins that mediate these distinct interactions are collectively called cell adhesion molecules and are divided into four major groups: cadherins, integrins, selectins, and immunoglobulins. They not only physically anchor cells, but also critically integrate signaling between the extracellular microenvironment and cells. These signals include biochemical cues, as adhesion proteins can both act as ligand-activated receptors and activate mechanotransduction triggered by changes in the physical environment. Molecular mechanisms related to cell adhesion signaling have been extensively studied, especially because mutations and changes in expression of these proteins, particularly cadherins and integrins, are frequently associated with diseases ranging from developmental intellectual disability to cancer. In fact, two major hallmarks of cancer, loss of cell-to-cell adhesion and anchorage-independent growth, are both dependent on cell adhesion molecules. Despite many studies elucidating the relationships between malignant transformation and metastasis and cellular adhesion processes, several areas still await exploration. Here, we highlight recently discovered roles of adhesion molecules in collective cancer cell migration and discuss the utility of three-dimensional models in studying cell-cell adhesion. We also describe recent therapeutic approaches targeting adhesion molecules.
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Affiliation(s)
- Michalina Janiszewska
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, Florida 33458.
| | - Marina Candido Primi
- Cell Adhesion Laboratory, Department of Integrative Structural and Computational Biology, The Scripps Research Institute, Jupiter, Florida 33458
| | - Tina Izard
- Cell Adhesion Laboratory, Department of Integrative Structural and Computational Biology, The Scripps Research Institute, Jupiter, Florida 33458
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19
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Patil DN, Rangarajan ES, Novick SJ, Pascal BD, Kojetin DJ, Griffin PR, Izard T, Martemyanov KA. Structural organization of a major neuronal G protein regulator, the RGS7-Gβ5-R7BP complex. eLife 2018; 7:42150. [PMID: 30540250 PMCID: PMC6310461 DOI: 10.7554/elife.42150] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [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: 09/18/2018] [Accepted: 12/12/2018] [Indexed: 01/03/2023] Open
Abstract
Signaling by the G-protein-coupled receptors (GPCRs) plays fundamental role in a vast number of essential physiological functions. Precise control of GPCR signaling requires action of regulators of G protein signaling (RGS) proteins that deactivate heterotrimeric G proteins. RGS proteins are elaborately regulated and comprise multiple domains and subunits, yet structural organization of these assemblies is poorly understood. Here, we report a crystal structure and dynamics analyses of the multisubunit complex of RGS7, a major regulator of neuronal signaling with key roles in controlling a number of drug target GPCRs and links to neuropsychiatric disease, metabolism, and cancer. The crystal structure in combination with molecular dynamics and mass spectrometry analyses reveals unique organizational features of the complex and long-range conformational changes imposed by its constituent subunits during allosteric modulation. Notably, several intermolecular interfaces in the complex work in synergy to provide coordinated modulation of this key GPCR regulator.
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Affiliation(s)
- Dipak N Patil
- Department of Neuroscience, The Scripps Research Institute, Jupiter, United States
| | - Erumbi S Rangarajan
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, Jupiter, United States
| | - Scott J Novick
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, United States
| | - Bruce D Pascal
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, United States
| | - Douglas J Kojetin
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, Jupiter, United States
| | - Patrick R Griffin
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, Jupiter, United States.,Department of Molecular Medicine, The Scripps Research Institute, Jupiter, United States
| | - Tina Izard
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, Jupiter, United States
| | - Kirill A Martemyanov
- Department of Neuroscience, The Scripps Research Institute, Jupiter, United States
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20
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Chinthalapudi K, Izard T. Molecular Mechanisms for Distinct Functions of Talin Isoforms. Biophys J 2018. [DOI: 10.1016/j.bpj.2017.11.3524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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21
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Cao W, Kayama H, Chen ML, Delmas A, Sun A, Kim SY, Rangarajan ES, McKevitt K, Beck AP, Jackson CB, Crynen G, Oikonomopoulos A, Lacey PN, Martinez GJ, Izard T, Lorenz RG, Rodriguez-Palacios A, Cominelli F, Abreu MT, Hommes DW, Koralov SB, Takeda K, Sundrud MS. The Xenobiotic Transporter Mdr1 Enforces T Cell Homeostasis in the Presence of Intestinal Bile Acids. Immunity 2017; 47:1182-1196.e10. [PMID: 29262351 DOI: 10.1016/j.immuni.2017.11.012] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 07/27/2017] [Accepted: 11/07/2017] [Indexed: 12/13/2022]
Abstract
CD4+ T cells are tightly regulated by microbiota in the intestine, but whether intestinal T cells interface with host-derived metabolites is less clear. Here, we show that CD4+ T effector (Teff) cells upregulated the xenobiotic transporter, Mdr1, in the ileum to maintain homeostasis in the presence of bile acids. Whereas wild-type Teff cells upregulated Mdr1 in the ileum, those lacking Mdr1 displayed mucosal dysfunction and induced Crohn's disease-like ileitis following transfer into Rag1-/- hosts. Mdr1 mitigated oxidative stress and enforced homeostasis in Teff cells exposed to conjugated bile acids (CBAs), a class of liver-derived emulsifying agents that actively circulate through the ileal mucosa. Blocking ileal CBA reabsorption in transferred Rag1-/- mice restored Mdr1-deficient Teff cell homeostasis and attenuated ileitis. Further, a subset of ileal Crohn's disease patients displayed MDR1 loss of function. Together, these results suggest that coordinated interaction between mucosal Teff cells and CBAs in the ileum regulate intestinal immune homeostasis.
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Affiliation(s)
- Wei Cao
- Department of Immunology and Microbiology, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Hisako Kayama
- Department of Microbiology and Immunology, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan
| | - Mei Lan Chen
- Department of Immunology and Microbiology, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Amber Delmas
- Department of Immunology and Microbiology, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Amy Sun
- Department of Pathology , New York University School of Medicine, New York, NY 10016, USA
| | - Sang Yong Kim
- Rodent Genetic Engineering Core , New York University School of Medicine, New York, NY 10016, USA
| | - Erumbi S Rangarajan
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Kelly McKevitt
- Department of Immunology and Microbiology, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Amanda P Beck
- Department of Veterinary Sciences, MD Anderson Cancer Center, Bastrop, TX 78602, USA
| | - Cody B Jackson
- Department of Immunology and Microbiology, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Gogce Crynen
- Bioinformatics Core Facility, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Angelos Oikonomopoulos
- Vatche and Tamar Manoukian Division of Digestive Diseases, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Precious N Lacey
- Vatche and Tamar Manoukian Division of Digestive Diseases, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Gustavo J Martinez
- Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA
| | - Tina Izard
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Robin G Lorenz
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Alex Rodriguez-Palacios
- Digestive Health Research Institute, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Fabio Cominelli
- Digestive Health Research Institute, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Maria T Abreu
- Division of Gastroenterology, Department of Medicine, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Daniel W Hommes
- Vatche and Tamar Manoukian Division of Digestive Diseases, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Sergei B Koralov
- Department of Pathology , New York University School of Medicine, New York, NY 10016, USA
| | - Kiyoshi Takeda
- Department of Microbiology and Immunology, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan
| | - Mark S Sundrud
- Department of Immunology and Microbiology, The Scripps Research Institute, Jupiter, FL 33458, USA.
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22
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Mediouni S, Ekka M, Chinthalapudi K, Usui I, Mousseau G, Jablonski J, Clementz M, Nowak J, Beverage J, Esquenazi E, Nettles K, Baran P, Loret E, Izard T, Maiti S, Valente S. Molecular characterisation of the inhibitor didehydro-Cortistatin A with the HIV-1 Tat protein. J Virus Erad 2017. [DOI: 10.1016/s2055-6640(20)30679-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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23
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Stender JD, Nwachukwu JC, Kastrati I, Kim Y, Strid T, Yakir M, Srinivasan S, Nowak J, Izard T, Rangarajan ES, Carlson KE, Katzenellenbogen JA, Yao XQ, Grant BJ, Leong HS, Lin CY, Frasor J, Nettles KW, Glass CK. Structural and Molecular Mechanisms of Cytokine-Mediated Endocrine Resistance in Human Breast Cancer Cells. Mol Cell 2017; 65:1122-1135.e5. [PMID: 28306507 DOI: 10.1016/j.molcel.2017.02.008] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 02/02/2017] [Accepted: 02/09/2017] [Indexed: 02/07/2023]
Abstract
Human breast cancers that exhibit high proportions of immune cells and elevated levels of pro-inflammatory cytokines predict poor prognosis. Here, we demonstrate that treatment of human MCF-7 breast cancer cells with pro-inflammatory cytokines results in ERα-dependent activation of gene expression and proliferation, in the absence of ligand or presence of 4OH-tamoxifen (TOT). Cytokine activation of ERα and endocrine resistance is dependent on phosphorylation of ERα at S305 in the hinge domain. Phosphorylation of S305 by IKKβ establishes an ERα cistrome that substantially overlaps with the estradiol (E2)-dependent ERα cistrome. Structural analyses suggest that S305-P forms a charge-linked bridge with the C-terminal F domain of ERα that enables inter-domain communication and constitutive activity from the N-terminal coactivator-binding site, revealing the structural basis of endocrine resistance. ERα therefore functions as a transcriptional effector of cytokine-induced IKKβ signaling, suggesting a mechanism through which the tumor microenvironment controls tumor progression and endocrine resistance.
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Affiliation(s)
- Joshua D Stender
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jerome C Nwachukwu
- Department of Cancer Biology, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Irida Kastrati
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Yohan Kim
- Department of Pathology and Laboratory Medicine, Schulich School of Medicine and Dentistry, Western University, London, ON N6A 5C1, Canada
| | - Tobias Strid
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Maayan Yakir
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Sathish Srinivasan
- Department of Cancer Biology, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Jason Nowak
- Department of Cancer Biology, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Tina Izard
- Department of Cancer Biology, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Erumbi S Rangarajan
- Department of Cancer Biology, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Kathryn E Carlson
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, IL 61801, USA
| | - John A Katzenellenbogen
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, IL 61801, USA
| | - Xin-Qiu Yao
- Department of Computational Medicine and Bioinformatics, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Barry J Grant
- Department of Computational Medicine and Bioinformatics, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Hon S Leong
- Department of Surgery, Schulich School of Medicine and Dentistry, Western University, London, ON N6A 5C1, Canada
| | - Chin-Yo Lin
- Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA
| | - Jonna Frasor
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Kendall W Nettles
- Department of Cancer Biology, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Christopher K Glass
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA.
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Sundrud MS, Cao W, Kayama H, Chen ML, Delmas A, Sun A, Kim SY, McKevitt K, Rangarajan ES, Beck AP, Oikonomopoulos A, Lacey PN, Martinez GJ, Izard T, Lorenz RG, Rodriguez-Palacios A, Cominelli F, Abreu MT, Hommes DW, Koralov SB, Takeda K. The xenobiotic transporter Mdr1 permits T cell adaptation to mucosa-associated bile acids in the ileum. The Journal of Immunology 2017. [DOI: 10.4049/jimmunol.198.supp.65.14] [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] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
Intestinal CD4+ T helper (TH) cells are subject to extensive regulation by microbiota. By contrast, it is not known whether or how TH cells interface with other, host-derived intestinal metabolites. Here we show that bile acids directly regulate mucosal TH cell function in the distal small intestine (i.e., ileum) via the xenobiotic transporter, Mdr1. Using both Mdr1-dependent dye efflux and a novel CRISPR-generated Mdr1 reporter mouse, we show that wild type RORγt+IL-17A+ (Th17) and RORγt-IFNγ+ (Th1) cells upregulate Mdr1 expression upon migration into the ileum. By contrast, germline ablation or shRNAmir-mediated knockdown of Mdr1 in Th17 and Th1 cells results in local dysfunction in the ileum, and these cells transfer Crohn’s disease-like ileitis in Rag1−/− hosts. Mdr1 enforces Th17 and Th1 cell survival and limits pro-inflammatory cytokine (TNFα, IFNγ) expression in the presence of conjugated bile acids (CBAs), which are actively reabsorbed through the ileal mucosa as a function of enterohepatic bile acid circulation. Accordingly, genetic or pharmacologic blockade of ileal CBA reabsorption restores Mdr1-deficient Th17 and Th1 cell homeostasis in ilea of transferred Rag1−/− hosts and rescues ileitis. In addition, MDR1 loss-of-function is evident in both ileitis-prone (SAMP1/YitFc) mice, and a subset of ileal Crohn’s disease patients. These data indicate that coordinated, local and druggable interactions between mucosal TH cells and mucosa-associated bile acids in the ileum contribute to intestinal immune homeostasis.
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25
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Abstract
The cytoskeletal protein vinculin is a major regulator of cell adhesion and attaches to the cell surface by binding to specific phospholipids. Structural, biochemical, and biological studies provided much insight into how vinculin binds to membranes, what components it recognizes, and how lipid binding is regulated. Here we discuss the roles and mechanisms of phospholipids in regulating the structure and function of vinculin and of its muscle-specific metavinculin splice variant. A full appreciation of these processes is necessary for understanding how vinculin regulates cell motility, migration, and wound healing, and for understanding of its role in cancer and cardiovascular diseases.
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Affiliation(s)
- Tina Izard
- From the Cell Adhesion Laboratory, Department of Cancer Biology and Department of Immunology and Microbial Sciences, The Scripps Research Institute, Jupiter, Florida 33458 and
| | - David T Brown
- the Department of Biochemistry, University of Mississippi Medical Center, Jackson, Mississippi 39216
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26
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Abstract
Vinculin localizes to cellular adhesions where it regulates motility, migration, development, wound healing, and response to force. Importantly, vinculin loss results in cancer phenotypes, cardiovascular disease, and embryonic lethality. At the plasma cell membrane, the most abundant phosphoinositide, phosphatidylinositol 4,5-bisphosphate (PIP2), binds the vinculin tail domain, Vt, and triggers homotypic and heterotypic interactions that amplify binding of vinculin to the actin network. Binding of PIP2 to Vt is necessary for maintaining optimal focal adhesions, for organizing stress fibers, for cell migration and spreading, and for the control of vinculin dynamics and turnover of focal adhesions. While the recently determined Vt/PIP2 crystal structure revealed the conformational changes occurring upon lipid binding and oligomerization, characterization of PIP2-induced vinculin oligomerization has been challenging in the adhesion biology field. Here, via a series of novel biochemical assays not performed in previous studies that relied on chemical cross-linking, we characterize the PIP2-induced vinculin oligomerization. Our results show that Vt/PIP2 forms a tight dimer with Vt or with the muscle-specific vinculin isoform, metavinculin, at sites of adhesion at the cell membrane. Insight into how PIP2 regulates clustering and into mechanisms that regulate cell adhesion allows the development for a more definite sensor for PIP2, and our developed techniques can be applied generally and thus open the door for the characterization of many other protein/PIP2 complexes under physiological conditions.
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Affiliation(s)
- Krishna Chinthalapudi
- †Cell Adhesion Laboratory, ‡Department of Cancer Biology, and §Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, Florida 33458, United States
| | - Dipak N Patil
- †Cell Adhesion Laboratory, ‡Department of Cancer Biology, and §Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, Florida 33458, United States
| | - Erumbi S Rangarajan
- †Cell Adhesion Laboratory, ‡Department of Cancer Biology, and §Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, Florida 33458, United States
| | - Christoph Rader
- †Cell Adhesion Laboratory, ‡Department of Cancer Biology, and §Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, Florida 33458, United States
| | - Tina Izard
- †Cell Adhesion Laboratory, ‡Department of Cancer Biology, and §Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, Florida 33458, United States
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27
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Chinthalapudi K, Rangarajan ES, Patil DN, George EM, Brown DT, Izard T. Lipid binding promotes oligomerization and focal adhesion activity of vinculin. ACTA ACUST UNITED AC 2015; 207:643-56. [PMID: 25488920 PMCID: PMC4259812 DOI: 10.1083/jcb.201404128] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [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] [Indexed: 01/09/2023]
Abstract
PIP2 binds vinculin and directs its oligomerization, which promotes proper focal adhesion structure and function. Adherens junctions (AJs) and focal adhesion (FA) complexes are necessary for cell migration and morphogenesis, and for the development, growth, and survival of all metazoans. Vinculin is an essential regulator of both AJs and FAs, where it provides links to the actin cytoskeleton. Phosphatidylinositol 4,5-bisphosphate (PIP2) affects the functions of many targets, including vinculin. Here we report the crystal structure of vinculin in complex with PIP2, which revealed that PIP2 binding alters vinculin structure to direct higher-order oligomerization and suggests that PIP2 and F-actin binding to vinculin are mutually permissive. Forced expression of PIP2-binding–deficient mutants of vinculin in vinculin-null mouse embryonic fibroblasts revealed that PIP2 binding is necessary for maintaining optimal FAs, for organization of actin stress fibers, and for cell migration and spreading. Finally, photobleaching experiments indicated that PIP2 binding is required for the control of vinculin dynamics and turnover in FAs. Thus, through oligomerization, PIP2 directs a transient vinculin sequestration at FAs that is necessary for proper FA function.
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Affiliation(s)
- Krishna Chinthalapudi
- Cell Adhesion Laboratory, Department of Cancer Biology, The Scripps Research Institute, Jupiter, FL 33458
| | - Erumbi S Rangarajan
- Cell Adhesion Laboratory, Department of Cancer Biology, The Scripps Research Institute, Jupiter, FL 33458
| | - Dipak N Patil
- Cell Adhesion Laboratory, Department of Cancer Biology, The Scripps Research Institute, Jupiter, FL 33458
| | - Eric M George
- Department of Biochemistry and Department of Physiology, University of Mississippi Medical Center, Jackson, MS 39216 Department of Biochemistry and Department of Physiology, University of Mississippi Medical Center, Jackson, MS 39216
| | - David T Brown
- Department of Biochemistry and Department of Physiology, University of Mississippi Medical Center, Jackson, MS 39216
| | - Tina Izard
- Cell Adhesion Laboratory, Department of Cancer Biology, The Scripps Research Institute, Jupiter, FL 33458
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28
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Chinthalapudi K, Rangarajan E, Patil D, Izard T. Lipid-directed cytoskeletal protein oligomerization at sites of cell adhesion. Acta Crystallogr A Found Adv 2014. [DOI: 10.1107/s2053273314081674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Vertebrate cell growth, division, migration, morphogenesis, and development, rely on the dynamic interactions of cells with components the extracellular matrix (ECM) via cell surface complexes. These focal adhesions (FAs) are comprised of integrin receptors, associated signaling molecules, and talin, which is required for "inside-out" signaling that stabilizes contacts of integrin receptors with the ECM by linking FAs to the actin cytoskeleton by binding to vinculin. The highly dynamic interactions with the actin cytoskeleton are also essential for the formation of membrane protrusions (lamellopodia and filopodia). Second messengers are found at the plasma cell membrane and include signaling lipids such as phosphoinositides, which play essential roles in signal transduction pathways and in directing the oligomerization of cytoskeletal proteins that function as essential links of FAs to the actin cytoskeleton. Notably, the most abundant phosphoinositide, phosphatidyl (4,5) bisphosphate (PIP2), directly binds to key cytoskeletal proteins, where it triggers homotypic and heterotypic interactions that amplify binding to the actin network. Binding of the inositol head group and the hydrophobic acyl chain pose difficulties in generating protein/PIP2 complex crystals and here we present the only second non-membrane protein structure of such a complex. Our crystal structure and biochemical approaches define the roles of PIP2 in controlling the oligomerization of cytoskeletal proteins and their binding to adhesion receptors and to the actin cytoskeleton. Importantly, we also determined the contribution of PIP2-directed oligomerization of cytoskeletal proteins to the formation and stabilization of adhesion complexes. These studies provide important new insights into how dynamic interactions of cytoskeletal proteins with the lipid membrane, adhesion complexes, and the actin network direct the mechanical behaviors of cells.
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29
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Poussin K, Pilati C, Couchy G, Calderaro J, Bioulac-Sage P, Bacq Y, Paradis V, Leteurtre E, Sturm N, Ramos J, Guettier C, Bardier-Dupas A, Boulai A, Wendum D, Selves J, Izard T, Nault JC, Zucman-Rossi J. Biochemical and functional analyses of gp130 mutants unveil JAK1 as a novel therapeutic target in human inflammatory hepatocellular adenoma. Oncoimmunology 2014; 2:e27090. [PMID: 24501689 PMCID: PMC3913689 DOI: 10.4161/onci.27090] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 11/04/2013] [Indexed: 01/05/2023] Open
Abstract
Inflammatory hepatocellular adenomas (IHCAs) are benign liver lesions that can be characterized histologically by the presence of an inflammatory infiltrate and at the molecular level by the overexpression of acute phase inflammatory response genes. Recurrent somatic mutations of the interleukin-6 (IL-6) signal transducer (IL6ST) locus, encoding the critical component of the IL-6 signal transduction machinery gp130, are present in 60% of IHCAs and in a subset (2%) of hepatocellular carcinoma (HCCs). By screening of 256 human hepatic adenoma specimens (the largest genetic analysis of IL6ST performed to date in this setting), we identified 24 distinct somatic IL6ST mutations among 66 mutant adenomas. The functional analysis of nine different gp130 mutants expressed in hepatic cancer cell lines consistently revealed the constitutive and IL-6-independent activation of the JAK/STAT signaling pathway. We further demonstrated that the signaling activity of mutant gp130 in IHCA remains responsive to suppressor of cytokine signaling 3 (SOCS3), a physiological gp130 inhibitor. Specifically, cells expressing a double mutant variant of gp130 with a disrupted SOCS3-binding site at residue 759 (Y186/Y759F) displayed a hyperactivation of signal transducer and activator of transcription 3 (STAT3) as compared with cells expressing the endogenous IHCA-associated Y186 gp130 mutant. Notably, we identified that constitutive signaling via gp130 in IHCA requires the Janus kinase family member JAK1, but not JAK2 or tyrosine kinase 2. In support of this notion, AG490, a tyrosine kinase inhibitor that selectively blocks JAK2, had no effect on gp130 activity. In stark contrast, we showed that ruxolitinib, a JAK1/JAK2-selective tyrosine kinase inhibitor used to treat patients with myelofibrosis, dramatically impaired JAK1-STAT signaling downstream of all IHCA-associated gp130 mutants. In conclusion, our findings provide a rationale for the use of JAK1 inhibitors for the treatment of HCAs expressing mutant gp130 as well as a subset of HCCs that bear similar mutations.
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Affiliation(s)
- Karine Poussin
- INSERM, UMR-674; Génomique fonctionnelle des tumeurs solides; IUH; Paris, France ; Université Paris Descartes; Labex Immuno-oncology; Sorbonne Paris Cité; Faculté de Médecine; Paris, France
| | - Camilla Pilati
- INSERM, UMR-674; Génomique fonctionnelle des tumeurs solides; IUH; Paris, France ; Université Paris Descartes; Labex Immuno-oncology; Sorbonne Paris Cité; Faculté de Médecine; Paris, France
| | - Gabrielle Couchy
- INSERM, UMR-674; Génomique fonctionnelle des tumeurs solides; IUH; Paris, France ; Université Paris Descartes; Labex Immuno-oncology; Sorbonne Paris Cité; Faculté de Médecine; Paris, France
| | - Julien Calderaro
- INSERM, UMR-674; Génomique fonctionnelle des tumeurs solides; IUH; Paris, France ; Université Paris Descartes; Labex Immuno-oncology; Sorbonne Paris Cité; Faculté de Médecine; Paris, France ; Assistance Publique-Hôpitaux de Paris; Department of Pathology; CHU Henri Mondor; Créteil, France
| | - Paulette Bioulac-Sage
- Inserm, UMR-1053; Université Victor Segalen Bordeaux 2; Bordeaux, France ; CHU de Bordeaux; Pellegrin Hospital; Department of Pathology; Bordeaux, France
| | - Yannick Bacq
- Service d'Hépatogastroentérologie; Hôpital Trousseau; CHRU de Tours; Tours, France
| | - Valérie Paradis
- Assistance Publique-Hôpitaux de Paris; Department of Pathology; Beaujon Hospital; Université Paris Diderot; Clichy, France
| | - Emmanuelle Leteurtre
- Université de Lille 2; Lille, France ; Institut de Pathologie; CHRU de Lille; Lille, France ; INSERM U837; Lille, France
| | - Nathalie Sturm
- Depatment of Pathology; CHU Grenoble; Hôpital Albert Michallon; La Tronche, France
| | - Jeanne Ramos
- Department of Pathology; Gui de Chauliac Hospital; Université Montpellier-Nîmes; Montpellier, France
| | - Catherine Guettier
- Department of Pathology; Assistance Publique-Hôpitaux de Paris; Hôpital Paul Brousse; Villejuif, France
| | - Armelle Bardier-Dupas
- Assistance Publique-Hôpitaux de Paris; Department of Pathology; Groupe Hospitalier Pitié-Salpêtrière; Université Pierre et Marie Curie; Paris, France
| | - Anais Boulai
- INSERM, UMR-674; Génomique fonctionnelle des tumeurs solides; IUH; Paris, France ; Université Paris Descartes; Labex Immuno-oncology; Sorbonne Paris Cité; Faculté de Médecine; Paris, France
| | - Dominique Wendum
- UPMC Univ Paris 06; UMRS 938; CdR Saint-Antoine; Paris, France ; INSERM, UMRS 938; CdR Saint-Antoine; Paris, France ; AP-HP, Hôpital St Antoine; Service d'Anatomie Pathologique; Paris, France
| | - Janick Selves
- Purpan Hospital; Pathology and Cancer Research Centre of Toulouse; Inserm UMR 1037/CNRS-ERL 5294/Toulouse 3 University; Markers & Targets for Digestive Cancer Biotherapy; Toulouse, France
| | - Tina Izard
- Department of Cancer Biology; The Scripps Research Institute; Scripps Florida; Jupiter, Florida USA
| | - Jean-Charles Nault
- INSERM, UMR-674; Génomique fonctionnelle des tumeurs solides; IUH; Paris, France ; Université Paris Descartes; Labex Immuno-oncology; Sorbonne Paris Cité; Faculté de Médecine; Paris, France
| | - Jessica Zucman-Rossi
- INSERM, UMR-674; Génomique fonctionnelle des tumeurs solides; IUH; Paris, France ; Université Paris Descartes; Labex Immuno-oncology; Sorbonne Paris Cité; Faculté de Médecine; Paris, France
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30
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Lee JH, Vonrhein C, Bricogne G, Izard T. Crystal structure of the N-terminal domains of the surface cell antigen 4 of Rickettsia. Protein Sci 2013; 22:1425-31. [PMID: 23904352 DOI: 10.1002/pro.2322] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 07/19/2013] [Accepted: 07/22/2013] [Indexed: 11/09/2022]
Abstract
The obligate intracellular, gram-negative bacterium Rickettsia is the causative agent of spotted fevers and typhus in humans. Surface cell antigen (sca) proteins surround these bacteria. We recently reported the co-localization of one of these proteins, sca4, with vinculin in cells at sites of focal adhesions and demonstrated that two vinculin binding sites directed the sca4/vinculin interaction. Here we report the 2.2 Å crystal structure of the conserved N-terminal 38 kDa domain of sca4 from Rickettsia rickettsii. The structure reveals two subdomains. The first is an all-helical domain that is folded in a fashion similar to the dimeric assembly chaperone for rubisco, namely RbcX. The following and highly conserved β-strand domain lacks significant structural similarity with other known structures and to the best of our knowledge represents a new protein fold.
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Affiliation(s)
- Jun Hyuck Lee
- Department of Cancer Biology, Cell Adhesion Laboratory, The Scripps Research Institute, Jupiter, Florida, 33458
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31
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Yogesha SD, Sharff A, Bricogne G, Izard T. Intermolecular versus intramolecular interactions of the vinculin binding site 33 of talin. Protein Sci 2013; 20:1471-6. [PMID: 21648001 DOI: 10.1002/pro.671] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The cytoskeletal proteins talin and vinculin are localized at cell-matrix junctions and are key regulators of cell signaling, adhesion, and migration. Talin couples integrins via its FERM domain to F-actin and is an important regulator of integrin activation and clustering. The 220 kDa talin rod domain comprises several four- and five-helix bundles that harbor amphipathic α-helical vinculin binding sites (VBSs). In its inactive state, the hydrophobic VBS residues involved in binding to vinculin are buried within these helix bundles, and the mechanical force emanating from bound integrin receptors is thought necessary for their release and binding to vinculin. The crystal structure of a four-helix bundle of talin that harbors one of these VBSs, coined VBS33, was recently determined. Here we report the crystal structure of VBS33 in complex with vinculin at 2 Å resolution. Notably, comparison of the apo and vinculin bound structures shows that intermolecular interactions of the VBS33 α-helix with vinculin are more extensive than the intramolecular interactions of the VBS33 within the talin four-helix bundle.
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Affiliation(s)
- S D Yogesha
- Cell Adhesion Laboratory, Department of Cancer Biology, The Scripps Research Institute, Jupiter, FL 33458, USA
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32
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Abstract
The F-actin binding cytoskeletal protein α-catenin interacts with
β-catenin-cadherin complexes and stabilizes cell-cell junctions. The
β-catenin–α-catenin complex cannot bind to F-actin,
whereas interactions of α-catenin with the cytoskeletal protein vinculin
appear necessary to stabilize adherens junctions. Here we report the crystal
structure of nearly full-length human α-catenin at 3.7 Å
resolution. α-Catenin forms an asymmetric dimer, where the four-helix
bundle domains of each subunit engage in distinct intermolecular interactions.
This results in a left handshake-like dimer, where the two subunits have
remarkably different conformations. The crystal structure explains why dimeric
α-catenin has a higher affinity for F-actin than monomeric
α-catenin, why the β-catenin–α-catenin complex
does not bind to F-actin, how activated vinculin links the cadherin-catenin
complex to the cytoskeleton, and why α-catenin but not inactive vinculin
can bind to F-actin.
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Affiliation(s)
- Erumbi S Rangarajan
- Department of Cancer Biology, Scripps Research Institute, Jupiter, Florida, USA
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33
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Lee JH, Rangarajan ES, Vonrhein C, Bricogne G, Izard T. The metavinculin tail domain directs constitutive interactions with raver1 and vinculin RNA. J Mol Biol 2012; 422:697-704. [PMID: 22709580 DOI: 10.1016/j.jmb.2012.06.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Revised: 05/02/2012] [Accepted: 06/11/2012] [Indexed: 11/26/2022]
Abstract
Vinculin is a key regulator of the actin cytoskeleton attachment to the cell membrane at cellular adhesion sites, which is crucial for processes such as cell motility and migration, development, survival, and wound healing. Vinculin loss results in embryonic lethality, cardiovascular diseases, and cancer. Its tail domain, Vt, is crucial for vinculin activation and focal adhesion turnover and binds to the actin cytoskeleton and acidic phospholipids upon which it unfurls. The RNA binding protein raver1 regulates the assembly of focal adhesions transcriptionally by binding to vinculin. The muscle-specific splice form, metavinculin, is characterized by a 68-residue insert in the tail domain (MVt) and correlates with hereditary idiopathic dilated cardiomyopathy. Here, we report that metavinculin can bind to raver1 in its inactive state. Our crystal structure explains this permissivity, where an extended coil unique to MVt is unfurled in the MVtΔ954:raver1 complex structure. Our binding assays show that raver1 forms a ternary complex with MVt and vinculin mRNA. These findings suggest that the metavinculin:raver1:RNA complex is constitutively recruited to adhesion complexes.
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Affiliation(s)
- Jun Hyuck Lee
- Department of Cancer Biology, Cell Adhesion Laboratory, The Scripps Research Institute, FL 33458, USA
| | - Erumbi S Rangarajan
- Department of Cancer Biology, Cell Adhesion Laboratory, The Scripps Research Institute, FL 33458, USA
| | - Clemens Vonrhein
- Global Phasing Ltd., Sheraton House, Castle Park, Cambridge CB3 0AX, UK
| | - Gerard Bricogne
- Global Phasing Ltd., Sheraton House, Castle Park, Cambridge CB3 0AX, UK
| | - Tina Izard
- Department of Cancer Biology, Cell Adhesion Laboratory, The Scripps Research Institute, FL 33458, USA.
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34
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Abstract
Adherens junctions (AJs) are essential for cell-cell contacts, morphogenesis, and the development of all higher eukaryotes. AJs are formed by calcium-dependent homotypic interactions of the ectodomains of single membrane-pass cadherin family receptors. These homotypic interactions in turn promote binding of the intracellular cytoplasmic tail domains of cadherin receptors with β-catenin, a multifunctional protein that plays roles in both transcription and AJs. The cadherin receptor-β-catenin complex binds to the cytoskeletal protein α-catenin, which is essential for both the formation and the stabilization of these junctions. Precisely how α-catenin contributes to the formation and stabilization of AJs is hotly debated, although the latter is thought to involve its interactions with the cytoskeletal protein vinculin. Here we report the crystal structure of the vinculin binding domain (VBD) of α-catenin in complex with the vinculin head domain (Vh1). This structure reveals that α-catenin is in a unique unfurled mode allowing dimer formation when bound to vinculin. Finally, binding studies suggest that vinculin must be in an activated state to bind to α-catenin and that this interaction is stabilized by the formation of a ternary α-catenin-vinculin-F-actin complex, which can be formed via the F-actin binding domain of either protein. We propose a feed-forward model whereby α-catenin-vinculin interactions promote their binding to the actin cytoskeleton to stabilize AJs.
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Affiliation(s)
- Erumbi S Rangarajan
- Department of Cancer Biology, The Scripps Research Institute, Jupiter, Florida 33458, USA
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35
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Yogesha SD, Rangarajan ES, Vonrhein C, Bricogne G, Izard T. Crystal structure of vinculin in complex with vinculin binding site 50 (VBS50), the integrin binding site 2 (IBS2) of talin. Protein Sci 2012; 21:583-8. [PMID: 22334306 DOI: 10.1002/pro.2041] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Revised: 02/01/2012] [Accepted: 02/02/2012] [Indexed: 11/06/2022]
Abstract
The cytoskeletal protein talin activates integrin receptors by binding of its FERM domain to the cytoplasmic tail of β-integrin. Talin also couples integrins to the actin cytoskeleton, largely by binding to and activating the cytoskeletal protein vinculin, which binds to F-actin through the agency of its five-helix bundle tail (Vt) domain. Talin activates vinculin by means of buried amphipathic α-helices coined vinculin binding sites (VBSs) that reside within numerous four- and five-helix bundle domains that comprise the central talin rod, which are released from their buried locales by means of mechanical tension on the integrin:talin complex. In turn, these VBSs bind to the N-terminal seven-helix bundle (Vh1) domain of vinculin, creating an entirely new helix bundle that severs its head-tail interactions. Interestingly, talin harbors a second integrin binding site coined IBS2 that consists of two five-helix bundle domains that also contain a VBS (VBS50). Here we report the crystal structure of VBS50 in complex with vinculin at 2.3 Å resolution and show that intramolecular interactions of VBS50 within IBS2 are much more extensive versus its interactions with vinculin. Indeed, the IBS2-vinculin interaction only occurs at physiological temperature and the affinity of VBS50 for vinculin is about 30 times less than other VBSs. The data support a model where integrin binding destabilizes IBS2 to allow it to bind to vinculin.
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Affiliation(s)
- S D Yogesha
- Department of Cancer Biology, Cell Adhesion Laboratory, The Scripps Research Institute, Jupiter, Florida 33458, USA
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36
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Yogesha SD, Sharff AJ, Giovannini M, Bricogne G, Izard T. Unfurling of the band 4.1, ezrin, radixin, moesin (FERM) domain of the merlin tumor suppressor. Protein Sci 2011; 20:2113-20. [PMID: 22012890 DOI: 10.1002/pro.751] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Accepted: 10/07/2011] [Indexed: 12/30/2022]
Abstract
The merlin-1 tumor suppressor is encoded by the Neurofibromatosis-2 (Nf2) gene and loss-of-function Nf2 mutations lead to nervous system tumors in man and to several tumor types in mice. Merlin is an ERM (ezrin, radixin, moesin) family cytoskeletal protein that interacts with other ERM proteins and with components of cell-cell adherens junctions (AJs). Merlin stabilizes the links of AJs to the actin cytoskeleton. Thus, its loss destabilizes AJs, promoting cell migration and invasion, which in Nf2(+/-) mice leads to highly metastatic tumors. Paradoxically, the "closed" conformation of merlin-1, where its N-terminal four-point-one, ezrin, radixin, moesin (FERM) domain binds to its C-terminal tail domain, directs its tumor suppressor functions. Here we report the crystal structure of the human merlin-1 head domain when crystallized in the presence of its tail domain. Remarkably, unlike other ERM head-tail interactions, this structure suggests that binding of the tail provokes dimerization and dynamic movement and unfurling of the F2 motif of the FERM domain. We conclude the "closed" tumor suppressor conformer of merlin-1 is in fact an "open" dimer whose functions are disabled by Nf2 mutations that disrupt this architecture.
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Affiliation(s)
- S D Yogesha
- Cell Adhesion Laboratory, Department of Cancer Biology, The Scripps Research Institute, Jupiter, Florida 33458, USA
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37
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Park H, Lee JH, Gouin E, Cossart P, Izard T. The rickettsia surface cell antigen 4 applies mimicry to bind to and activate vinculin. J Biol Chem 2011; 286:35096-103. [PMID: 21841197 DOI: 10.1074/jbc.m111.263855] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Pathogenic Rickettsia species cause high morbidity and mortality, especially R. prowazekii, the causative agent of typhus. Like many intracellular pathogens, Rickettsia exploit the cytoskeleton to enter and spread within the host cell. Here we report that the cell surface antigen sca4 of Rickettsia co-localizes with vinculin in cells at sites of focal adhesions in sca4-transfected cells and that sca4 binds to and activates vinculin through two vinculin binding sites (VBSs) that are conserved across all Rickettsia. Remarkably, this occurs through molecular mimicry of the vinculin-talin interaction that is also seen with the IpaA invasin of the intracellular pathogen Shigella, where binding of these VBSs to the vinculin seven-helix bundle head domain (Vh1) displaces intramolecular interactions with the vinculin tail domain that normally clamp vinculin in an inactive state. Finally, the vinculin·sca4-VBS crystal structures reveal that vinculin adopts a new conformation when bound to the C-terminal VBS of sca4. Collectively, our data define the mechanism by which sca4 activates vinculin and interacts with the actin cytoskeleton, and they suggest important roles for vinculin in Rickettsia pathogenesis.
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Affiliation(s)
- HaJeung Park
- Cell Adhesion Laboratory, Department of Cancer Biology, The Scripps Research Institute, Jupiter, Florida 33458, USA
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38
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Park H, Valencia-Gallardo C, Sharff A, Van Nhieu GT, Izard T. Novel vinculin binding site of the IpaA invasin of Shigella. J Biol Chem 2011; 286:23214-21. [PMID: 21525010 PMCID: PMC3123088 DOI: 10.1074/jbc.m110.184283] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2010] [Revised: 04/05/2011] [Indexed: 11/06/2022] Open
Abstract
Internalization of Shigella into host epithelial cells, where the bacteria replicates and spreads to neighboring cells, requires a type 3 secretion system (T3SS) effector coined IpaA. IpaA binds directly to and activates the cytoskeletal protein vinculin after injection in the host cell cytosol, and this was previously thought to be directed by two amphipathic α-helical vinculin-binding sites (VBS) found in the C-terminal tail domain of IpaA. Here, we report a third VBS, IpaA-VBS3, that is located N-terminal to the other two VBSs of IpaA and show that one IpaA molecule can bind up to three vinculin molecules. Biochemical in vitro Shigella invasion assays and the 1.6 Å crystal structure of the vinculin·IpaA-VBS3 complex showed that IpaA-VBS3 is functionally redundant with the other two IpaA-VBSs in cell invasion and in activating the latent F-actin binding functions of vinculin. Multiple VBSs in IpaA are reminiscent of talin, which harbors 11 VBSs. However, most of the talin VBSs have low affinity and are buried in helix bundles, whereas all three of the VBSs of IpaA are high affinity, readily available, and in close proximity to each other in the IpaA structure. Although deletion of IpaA-VBS3 has no detectable effects on Shigella invasion of epithelial cells, deletion of all three VBSs impaired bacterial invasion to levels found in an ipaA null mutant strain. Thus, IpaA-directed mimicry of talin in activating vinculin occurs through three high affinity VBSs that are essential for Shigella pathogenesis.
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Affiliation(s)
- HaJeung Park
- From the Cell Adhesion Laboratory, Department of Cancer Biology, Scripps Research Institute, Jupiter, Florida 33458
| | - Cesar Valencia-Gallardo
- the Unité de Communication Intercellulaire et Infections Microbiennes, Inserm U971, Collège de France, 75005 Paris Cedex, France, and
| | - Andrew Sharff
- Global Phasing Ltd., Sheraton House, Castle Park, Cambridge CB3 0AX, United Kingdom
| | - Guy Tran Van Nhieu
- the Unité de Communication Intercellulaire et Infections Microbiennes, Inserm U971, Collège de France, 75005 Paris Cedex, France, and
| | - Tina Izard
- From the Cell Adhesion Laboratory, Department of Cancer Biology, Scripps Research Institute, Jupiter, Florida 33458
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Pilati C, Amessou M, Bihl MP, Balabaud C, Nhieu JTV, Paradis V, Nault JC, Izard T, Bioulac-Sage P, Couchy G, Poussin K, Zucman-Rossi J. Somatic mutations activating STAT3 in human inflammatory hepatocellular adenomas. ACTA ACUST UNITED AC 2011; 208:1359-66. [PMID: 21690253 PMCID: PMC3135371 DOI: 10.1084/jem.20110283] [Citation(s) in RCA: 194] [Impact Index Per Article: 14.9] [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] [Indexed: 01/05/2023]
Abstract
Somatic STAT3 mutations present in a subset of inflammatory hepatocellular adenomas result in the generation of constitutively active STAT3 proteins that homodimerize independently of IL-6 stimulation. Inflammatory hepatocellular adenomas (IHCAs) are benign liver tumors. 60% of these tumors have IL-6 signal transducer (IL6ST; gp130) mutations that activate interleukin 6 (IL-6) signaling. Here, we report that 12% of IHCA subsets lacking IL6ST mutations harbor somatic signal transducer and activator of transcription 3 (STAT3) mutations (6/49). Most of these mutations are amino acid substitutions in the SH2 domain that directs STAT3 dimerization. In contrast to wild-type STAT3, IHCA STAT3 mutants constitutively activated the IL-6 signaling pathway independent of ligand in hepatocellular cells. Indeed, the IHCA STAT3 Y640 mutant homodimerized independent of IL-6 and was hypersensitive to IL-6 stimulation. This was associated with phosphorylation of tyrosine 705, a residue required for IL-6–induced STAT3 activation. Silencing or inhibiting the tyrosine kinases JAK1 or Src, which phosphorylate STAT3, impaired constitutive activity of IHCA STAT3 mutants in hepatocellular cells. Thus, we identified for the first time somatic STAT3 mutations in human tumors, revealing a new mechanism of recurrent STAT3 activation and underscoring the role of the IL-6–STAT3 pathway in benign hepatocellular tumorigenesis.
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Affiliation(s)
- Camilla Pilati
- Génomique fonctionnelle des tumeurs solides, Institut National de la Santé et de la Recherche Médicale (Inserm), U674, Paris, F-75010, France
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40
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Rangarajan ES, Lee JH, Izard T. Apo raver1 structure reveals distinct RRM domain orientations. Protein Sci 2011; 20:1464-70. [PMID: 21633983 DOI: 10.1002/pro.664] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2011] [Accepted: 05/06/2011] [Indexed: 11/08/2022]
Abstract
Raver1 is a multifunctional protein that modulates both alternative splicing and focal adhesion assembly by binding to the nucleoplasmic splicing repressor polypyrimidine tract protein (PTB) or to the cytoskeletal proteins vinculin and α-actinin. The amino-terminal region of raver1 has three RNA recognition motif (RRM1, RRM2, and RRM3) domains, and RRM1 interacts with the vinculin tail (Vt) domain and vinculin mRNA. We previously determined the crystal structure of the raver1 RRM1-3 domains in complex with Vt at 2.75 Å resolution. Here, we report crystal structure of the unbound raver1 RRM1-3 domains at 2 Å resolution. The apo structure reveals that a bound sulfate ion disrupts an electrostatic interaction between the RRM1 and RRM2 domains, triggering a large relative domain movement of over 30°. Superposition with other RNA-bound RRM structures places the sulfate ion near the superposed RNA phosphate group suggesting that this is the raver1 RNA binding site. While several single and some tandem RRM domain structures have been described, to the best of our knowledge, this is the second report of a three-tandem RRM domain structure.
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Affiliation(s)
- Erumbi S Rangarajan
- Cell Adhesion Laboratory, Department of Cancer Biology, The Scripps Research Institute, Jupiter, Florida 33458, USA
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41
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Rangarajan ES, Izard T. Improving the diffraction of full-length human selenomethionyl metavinculin crystals by streak-seeding. Acta Crystallogr Sect F Struct Biol Cryst Commun 2010; 66:1617-20. [PMID: 21139209 DOI: 10.1107/s1744309110041059] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2010] [Accepted: 10/12/2010] [Indexed: 11/10/2022]
Abstract
Metavinculin is an alternatively spliced isoform of vinculin that has a 68-residue insert in its tail domain (1134 total residues) and is exclusively expressed in cardiac and smooth muscle tissue, where it plays important roles in myocyte adhesion complexes. Mutations in the metavinculin-specific insert are associated with dilated cardiomyopathy (DCM) in man. Crystals of a DCM-associated mutant of full-length selenomethionine-labeled metavinculin grown by hanging-drop vapor diffusion diffracted poorly and were highly sensitive to radiation, preventing the collection of a complete X-ray diffraction data set at the highest possible resolution. Streak-seeding markedly improved the stability, crystal-growth rate and diffraction quality of DCM-associated mutant metavinculin crystals, allowing complete data collection to 3.9 Å resolution. These crystals belonged to space group P4(3)2(1)2, with two molecules in the asymmetric unit and unit-cell parameters a=b=170, c=211 Å, α=β=γ=90°.
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Affiliation(s)
- Erumbi S Rangarajan
- Cell Adhesion Laboratory, Department of Cancer Biology, The Scripps Research Institute, Scripps Florida, Jupiter, FL 33458, USA
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42
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George EM, Izard T, Anderson SD, Brown DT. Nucleosome interaction surface of linker histone H1c is distinct from that of H1(0). J Biol Chem 2010; 285:20891-6. [PMID: 20444700 PMCID: PMC2898364 DOI: 10.1074/jbc.m110.108639] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [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: 01/27/2010] [Revised: 05/04/2010] [Indexed: 11/06/2022] Open
Abstract
The fully organized structure of the eukaryotic nucleosome remains unsolved, in part due to limited information regarding the binding site of the H1 or linker histone. The central globular domain of H1 is believed to interact with the nucleosome core at or near the dyad and to bind at least two strands of DNA. We utilized site-directed mutagenesis and in vivo photobleaching to identify residues that contribute to the binding of the globular domain of the somatic H1 subtype H1c to the nucleosome. As was previously observed for the H1(0) subtype, the binding residues for H1c are clustered on the surface of one face of the domain. Despite considerable structural conservation between the globular domains of these two subtypes, the locations of the binding sites identified for H1c are distinct from those of H1(0). We suggest that the globular domains of these two linker histone subtypes will bind to the nucleosome with distinct orientations that may contribute to higher order chromatin structure heterogeneity or to differences in dynamic interactions with other DNA or chromatin-binding proteins.
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Affiliation(s)
- Eric M. George
- From the Department of Biochemistry, University of Mississippi Medical Center, Jackson, Mississippi 39216-4505 and
| | - Tina Izard
- the Cell Adhesion Laboratory, Department of Cancer Biology, The Scripps Research Institute, Jupiter, Florida 33458
| | - Stephen D. Anderson
- From the Department of Biochemistry, University of Mississippi Medical Center, Jackson, Mississippi 39216-4505 and
| | - David T. Brown
- From the Department of Biochemistry, University of Mississippi Medical Center, Jackson, Mississippi 39216-4505 and
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Park H, Rangarajan ES, Sygusch J, Izard T. Dramatic improvement of crystal quality for low-temperature-grown rabbit muscle aldolase. Acta Crystallogr Sect F Struct Biol Cryst Commun 2010; 66:595-600. [PMID: 20445268 PMCID: PMC2864701 DOI: 10.1107/s1744309110011875] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2009] [Accepted: 03/29/2010] [Indexed: 11/10/2022]
Abstract
Rabbit muscle aldolase (RMA) was crystallized in complex with the low-complexity domain (LC4) of sorting nexin 9. Monoclinic crystals were obtained at room temperature that displayed large mosaicity and poor X-ray diffraction. However, orthorhombic RMA-LC4 crystals grown at 277 K under similar conditions exhibited low mosaicity, allowing data collection to 2.2 A Bragg spacing and structure determination. It was concluded that the improvement of crystal quality as indicated by the higher resolution of the new RMA-LC4 complex crystals was a consequence of the introduction of new lattice contacts at lower temperature. The lattice contacts corresponded to an increased number of interactions between high-entropy side chains that mitigate the lattice strain incurred upon cryocooling and accompanying mosaic spread increases. The thermodynamically unfavorable immobilization of high-entropy side chains used in lattice formation was compensated by an entropic increase in the bulk-solvent content owing to the greater solvent content of the crystal lattice.
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Affiliation(s)
- HaJeung Park
- Cell Adhesion Laboratory, Department of Cancer Biology, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Erumbi S. Rangarajan
- Cell Adhesion Laboratory, Department of Cancer Biology, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Jurgen Sygusch
- Département de Biochimie, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Tina Izard
- Cell Adhesion Laboratory, Department of Cancer Biology, The Scripps Research Institute, Jupiter, FL 33458, USA
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44
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Abstract
Sorting nexin 9 (SNX9) functions in a complex with the GTPase dynamin-2 at clathrin-coated pits, where it provokes fission of vesicles to complete endocytosis. Here the SNX9.dynamin-2 complex binds to clathrin and adapter protein complex 2 (AP-2) that line these pits, and this occurs through interactions of the low complexity domain (LC4) of SNX9 with AP-2. Intriguingly, localization of the SNX9.dynamin-2 complex to clathrin-coated pits is blocked by interactions with the abundant glycolytic enzyme aldolase, which also binds to the LC4 domain of SNX9. The crystal structure of the LC4 motif of human SNX9 in complex with aldolase explains the biochemistry and biology of this interaction, where SNX9 binds near the active site of aldolase via residues 165-171 that are also required for the interactions of SNX9 with AP-2. Accordingly, SNX9 binding to aldolase is structurally precluded by the binding of substrate to the active site. Interactions of SNX9 with aldolase are far more extensive and differ from those of the actin-nucleating factor WASP with aldolase, indicating considerable plasticity in mechanisms that direct the functions of the aldolase as a scaffold protein.
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Affiliation(s)
- Erumbi S Rangarajan
- Department of Cancer Biology, The Scripps Research Institute, Jupiter, Florida 33458, USA
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Lee JH, Rangarajan ES, Yogesha SD, Izard T. Raver1 interactions with vinculin and RNA suggest a feed-forward pathway in directing mRNA to focal adhesions. Structure 2009; 17:833-42. [PMID: 19523901 DOI: 10.1016/j.str.2009.04.010] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2008] [Revised: 04/09/2009] [Accepted: 04/10/2009] [Indexed: 10/20/2022]
Abstract
The translational machinery of the cell relocalizes to focal adhesions following the activation of integrin receptors. This response allows for rapid, local production of components needed for adhesion complex assembly and signaling. Vinculin links focal adhesions to the actin cytoskeleton following its activation by integrin signaling, which severs intramolecular interactions of vinculin's head and tail (Vt) domains. Our vinculin:raver1 crystal structures and binding studies show that activated Vt selectively interacts with one of the three RNA recognition motifs of raver1, that the vinculin:raver1 complex binds to F-actin, and that raver1 binds selectively to RNA, including a sequence found in vinculin mRNA. Further, mutation of residues that mediate interaction of raver1 with vinculin abolish their colocalization in cells. These findings suggest a feed-forward model where vinculin activation at focal adhesions provides a scaffold for recruitment of raver1 and its mRNA cargo to facilitate the production of components of adhesion complexes.
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Affiliation(s)
- Jun Hyuck Lee
- Cell Adhesion Laboratory, Department of Cancer Biology, The Scripps Research Institute, Jupiter, FL 33458, USA
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46
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Van Nhieu GT, Izard T. Vinculin binding in its closed conformation by a helix addition mechanism. EMBO J 2008. [DOI: 10.1038/sj.emboj.7601971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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47
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Nhieu GTV, Izard T. Vinculin binding in its closed conformation by a helix addition mechanism. EMBO J 2007; 26:4588-96. [PMID: 17932491 DOI: 10.1038/sj.emboj.7601863] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2007] [Accepted: 08/30/2007] [Indexed: 01/22/2023] Open
Abstract
Vinculin links integrin receptors to the actin cytoskeleton by binding to talin. Vinculin is held in an inactive, closed-clamp conformation through hydrophobic interactions between its head and tail domains, and vinculin activation has long been thought to be dependent upon severing the head-tail interaction. Talin, alpha-actinin, and the invasin IpaA of Shigella flexneri sever vinculin's head-tail interaction by inserting an alpha-helix into vinculin's N-terminal four-helical bundle, provoking extensive conformational changes by a helical bundle conversion mechanism; these alterations in vinculin structure displace its tail domain, allowing vinculin to bind to its other partners. IpaA harbors two juxtaposed alpha-helical vinculin-binding sites (VBS) in its C-terminus. Here, we report that the lower affinity VBS of IpaA can also bind to the adjacent C-terminal four-helical bundle of vinculin's head domain through a helix addition mechanism. These hydrophobic interactions do not alter the conformation of this helical bundle, and the architecture of the complex suggests that IpaA can simultaneously interact with both of the four-helical bundle domains of vinculin's N-terminus to stabilize vinculin-IpaA interactions.
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Affiliation(s)
- Guy Tran Van Nhieu
- Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, Inserm U786, Paris, France
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St-Jean M, Izard T, Sygusch J. A hydrophobic pocket in the active site of glycolytic aldolase mediates interactions with Wiskott-Aldrich syndrome protein. J Biol Chem 2007; 282:14309-15. [PMID: 17329259 DOI: 10.1074/jbc.m611505200] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Aldolase plays essential catalytic roles in glycolysis and gluconeogenesis. However, aldolase is a highly abundant protein that is remarkably promiscuous in its interactions with other cellular proteins. In particular, aldolase binds to highly acidic amino acid sequences, including the C terminus of the Wiskott-Aldrich syndrome protein, an actin nucleation-promoting factor. Here we report the crystal structure of tetrameric rabbit muscle aldolase in complex with a C-terminal peptide of Wiskott-Aldrich syndrome protein. Aldolase recognizes a short, four-residue DEWD motif (residues 498-501), which adopts a loose hairpin turn that folds around the central aromatic residue, enabling its tryptophan side chain to fit into a hydrophobic pocket in the active site of aldolase. The flanking acidic residues in this binding motif provide further interactions with conserved aldolase active site residues Arg-42 and Arg-303, aligning their side chains and forming the sides of the hydrophobic pocket. The binding of Wiskott-Aldrich syndrome protein to aldolase precludes intramolecular interactions of its C terminus with its active site and is competitive with substrate as well as with binding by actin and cortactin. Finally, based on this structure, a novel naphthol phosphate-based inhibitor of aldolase was identified, and its structure in complex with aldolase demonstrated mimicry of the Wiskott-Aldrich syndrome protein-aldolase interaction. The data support a model whereby aldolase exists in distinct forms that regulate glycolysis or actin dynamics.
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Affiliation(s)
- Miguel St-Jean
- Department of Biochemistry, University of Montreal, Montreal, Quebec, Canada
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49
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Ramarao N, Le Clainche C, Izard T, Bourdet-Sicard R, Ageron E, Sansonetti PJ, Carlier MF, Tran Van Nhieu G. Capping of actin filaments by vinculin activated by the Shigella IpaA carboxyl-terminal domain. FEBS Lett 2007; 581:853-7. [PMID: 17289036 DOI: 10.1016/j.febslet.2007.01.057] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [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: 10/26/2006] [Revised: 01/15/2007] [Accepted: 01/22/2007] [Indexed: 11/23/2022]
Abstract
Shigella, the causative agent of bacillary dysentery, invades epithelial cells. Upon bacterial-cell contact, the type III bacterial effector IpaA binds to the cytoskeletal protein vinculin to promote actin reorganization required for efficient bacterial uptake. We show that the last 74 C-terminal residues of IpaA (A559) bind to human vinculin (HV) and promotes its association with actin filaments. Polymerisation experiments demonstrated that A559 was sufficient to induce HV-dependent partial capping of the barbed ends of actin filaments. These results suggest that IpaA regulates actin polymerisation/depolymerisation at sites of Shigella invasion by modulating the barbed end capping activity of vinculin.
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Affiliation(s)
- Nalini Ramarao
- Unité de Pathogénie Microbienne Moléculaire, Inserm U786, Institut Pasteur, 75724 Paris Cedex 15, France
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50
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Abstract
Shigella flexneri, the causative agent of bacillary dysentery, injects invasin proteins through a type III secretion apparatus upon contacting the host cell, which triggers pathogen internalization. The invasin IpaA is essential for S. flexneri pathogenesis and binds to the cytoskeletal protein vinculin to facilitate host cell entry. We report that IpaA harbors two vinculin-binding sites (VBSs) within its C-terminal domain that bind to and activate vinculin in a mutually exclusive fashion. Only the highest affinity C-terminal IpaA VBS is necessary for efficient entry and cell–cell spread of S. flexneri, whereas the lower affinity VBS appears to contribute to vinculin recruitment at entry foci of the pathogen. Finally, the crystal structures of vinculin in complex with the VBSs of IpaA reveal the mechanism by which IpaA subverts vinculin's functions, where S. flexneri utilizes a remarkable level of molecular mimicry of the talin–vinculin interaction to activate vinculin. Mimicry of vinculin's interactions may therefore be a general mechanism applied by pathogens to infect the host cell.
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Affiliation(s)
- Tina Izard
- Cell Adhesion Laboratory, Department of Oncology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
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