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Lee HS, Sun H, Lagarrigue F, Kim SHJ, Fox JW, Sherman NE, Gingras AR, Ginsberg MH. Phostensin enables lymphocyte integrin activation and population of peripheral lymphoid organs. J Exp Med 2022; 219:e20211637. [PMID: 35766979 PMCID: PMC9247717 DOI: 10.1084/jem.20211637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 01/17/2022] [Accepted: 03/28/2022] [Indexed: 02/03/2023] Open
Abstract
Rap1 GTPase drives assembly of the Mig-10/RIAM/Lamellipodin (MRL protein)-integrin-talin (MIT) complex that enables integrin-dependent lymphocyte functions. Here we used tandem affinity tag-based proteomics to isolate and analyze the MIT complex and reveal that Phostensin (Ptsn), a regulatory subunit of protein phosphatase 1, is a component of the complex. Ptsn mediates dephosphorylation of Rap1, thereby preserving the activity and membrane localization of Rap1 to stabilize the MIT complex. CRISPR/Cas9-induced deletion of PPP1R18, which encodes Ptsn, markedly suppresses integrin activation in Jurkat human T cells. We generated apparently healthy Ppp1r18-/- mice that manifest lymphocytosis and reduced population of peripheral lymphoid tissues ascribable, in part, to defective activation of integrins αLβ2 and α4β7. Ppp1r18-/- T cells exhibit reduced capacity to induce colitis in a murine adoptive transfer model. Thus, Ptsn enables lymphocyte integrin-mediated functions by dephosphorylating Rap1 to stabilize the MIT complex. As a consequence, loss of Ptsn ameliorates T cell-mediated colitis.
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Affiliation(s)
- Ho-Sup Lee
- Department of Medicine, University of California, San Diego, La Jolla, CA
| | - Hao Sun
- Department of Medicine, University of California, San Diego, La Jolla, CA
| | - Frédéric Lagarrigue
- Department of Medicine, University of California, San Diego, La Jolla, CA
- Institut de Pharmacologie et Biologie Structurale, Université de Toulouse, Centre National de la Recherche Scientifique, Université Paul Sabatier, Toulouse, France
| | - Sarah Hyun Ji Kim
- Department of Medicine, University of California, San Diego, La Jolla, CA
| | - Jay W. Fox
- School of Medicine, University of Virginia, Charlottesville, VA
| | | | | | - Mark H. Ginsberg
- Department of Medicine, University of California, San Diego, La Jolla, CA
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Lin YS, Huang KY, Yu HC, Lu MC, Fan CJ, Huang Tseng HY, Jhuang BY, Liu SQ, Lai NS, Lin TH, Huang HB. Identification of phostensin in association with Eps 15 homology domain-containing protein 1 (EHD1) and EHD4. Biochem Biophys Res Commun 2020; 531:236-241. [PMID: 32800345 DOI: 10.1016/j.bbrc.2020.07.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 07/07/2020] [Indexed: 11/17/2022]
Abstract
Phostensin (PTS) encoded by KIAA1949 is a protein phosphatase 1 (PP1)-binding protein. In order to explore the cellular functions of PTS, we have searched PTS-binding proteins by using co-immunoprecipitation in combination with shotgun proteomics. Here, we report two novel PTS-binding proteins, Eps 15 homology domain-containing protein 1 (EHD1) and EHD4. PTS associated with EHD proteins was also observed in GST pull-down assays. Immunofluorescence microscopy demonstrated that the complex was co-localized at the endocytic vesicles. EHD proteins have been known to play a critical role in regulation of endocytic transport. Overexpression of PTS-β can attenuate the endocytic trafficking of transferrin.
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Affiliation(s)
- Yu-Shan Lin
- Department of Biomedical Sciences, National Chung Cheng University, Chia-Yi, 621, Taiwan
| | - Kuang-Yung Huang
- Division of Allergy, Immunology and Rheumatology, Department of Medicine, Dalin Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Chia-Yi, 62247, Taiwan; School of Medicine, Tzu Chi University, Hualien, 970, Taiwan
| | - Hui-Chun Yu
- Division of Allergy, Immunology and Rheumatology, Department of Medicine, Dalin Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Chia-Yi, 62247, Taiwan
| | - Ming-Chi Lu
- Division of Allergy, Immunology and Rheumatology, Department of Medicine, Dalin Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Chia-Yi, 62247, Taiwan; School of Medicine, Tzu Chi University, Hualien, 970, Taiwan
| | - Cheng-Jhong Fan
- Department of Biomedical Sciences, National Chung Cheng University, Chia-Yi, 621, Taiwan
| | - Hsien-Yu Huang Tseng
- Department of Biomedical Sciences, National Chung Cheng University, Chia-Yi, 621, Taiwan
| | - Bi-Yao Jhuang
- Department of Biomedical Sciences, National Chung Cheng University, Chia-Yi, 621, Taiwan
| | - Su-Qin Liu
- Division of Allergy, Immunology and Rheumatology, Department of Medicine, Dalin Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Chia-Yi, 62247, Taiwan
| | - Ning-Sheng Lai
- Division of Allergy, Immunology and Rheumatology, Department of Medicine, Dalin Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Chia-Yi, 62247, Taiwan; School of Medicine, Tzu Chi University, Hualien, 970, Taiwan.
| | - Ta-Hsien Lin
- Division of Basic Research, Department of Medical Research, Taipei Veterans General Hospital, Taipei, 11217, Taiwan; Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei, 11221, Taiwan.
| | - Hsien-Bin Huang
- Department of Biomedical Sciences, National Chung Cheng University, Chia-Yi, 621, Taiwan.
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The Actin-Binding Protein PPP1r18 Regulates Maturation, Actin Organization, and Bone Resorption Activity of Osteoclasts. Mol Cell Biol 2018; 38:MCB.00425-17. [PMID: 29158294 DOI: 10.1128/mcb.00425-17] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 11/11/2017] [Indexed: 01/21/2023] Open
Abstract
Osteoclasts resorb bone by attaching on the bone matrix and forming a sealing zone. In Src-deficient mice, osteoclasts cannot form the actin ring, a characteristic actin structure that seals the resorbed area, and resorb hardly any bone as a result. However, the molecular mechanism underlying the role of Src in the regulation and organization of the actin ring is still unclear. We identified an actin-regulatory protein, protein phosphatase 1 regulatory subunit 18 (PPP1r18), as an Src-binding protein in an Src-, Yes-, and Fyn-deficient fibroblast (SYF) cell line overexpressing a constitutively active form of Src. PPP1r18 was localized in the nucleus and actin ring. PPP1r18 overexpression in osteoclasts inhibited terminal differentiation, actin ring formation, and bone-resorbing activity. A mutation of the protein phosphatase 1 (PP1)-binding domain of PPP1r18 rescued these phenotypes. In contrast, PPP1r18 knockdown promoted terminal differentiation and actin ring formation. In summary, we showed that PPP1r18 likely plays a role in podosome organization and bone resorption.
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Increased Serum Levels of Anti-Carbamylated 78-kDa Glucose-Regulated Protein Antibody in Patients with Rheumatoid Arthritis. Int J Mol Sci 2016; 17:ijms17091510. [PMID: 27618024 PMCID: PMC5037787 DOI: 10.3390/ijms17091510] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 08/30/2016] [Accepted: 09/05/2016] [Indexed: 12/22/2022] Open
Abstract
The objective of this study was to investigate the presence and titer of anti-carbamylated 78-kDa glucose-regulated protein (anti-CarGRP78) antibody in serum from controls, and patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) and primary Sjögren syndrome (pSS). Thirty-three RA patients, 20 SLE patients, 20 pSS patients, and 20 controls were enrolled from our outpatient clinic. GRP78 was cloned and carbamylated. Serum titers of anti- cyclic citrullinated peptides (anti-CCP), anti-GRP78, and anti-CarGRP78 were measured with an enzyme-linked immunosorbent assay. No differences in serum titers of anti-GRP78 antibody in patients with RA, SLE, or pSS compared with the controls were observed. Serum levels of anti-carGRP78 antibody in patients with RA, but not SLE or pSS, were significantly higher compared with the controls (OD405 0.15 ± 0.08 versus 0.11 ± 0.03, p = 0.033). There was a positive correlation between the serum levels of anti-GRP78 antibody, but not anti-CarGRP78 antibody, with the levels of anti-CCP antibody in patients with RA. Both anti-GRP78 and anti-carGRP78 antibodies failed to correlate with C-reactive protein levels in patients with RA. In conclusion, we demonstrated the presence of anti-CarGRP78 antibody in patients with RA. In addition, the serum titer of anti-CarGRP78 antibody was significantly elevated in patients with RA compared with the controls. Anti-CarGRP78 antibody could also be detected in patients with SLE or pSS.
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Lin YS, Huang HL, Liu WT, Lin TH, Huang HB. Identification of the high molecular weight isoform of phostensin. Int J Mol Sci 2014; 15:1068-79. [PMID: 24434620 PMCID: PMC3907856 DOI: 10.3390/ijms15011068] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Revised: 12/31/2013] [Accepted: 01/06/2014] [Indexed: 11/16/2022] Open
Abstract
Phostensin is encoded by KIAA1949. 5′-RACEanalysis has been used to identify the translation start site of phostensin mRNA, indicating that it encodes 165 amino acids with an apparent molecular weight of 26 kDa on SDS-PAGE. This low-molecular-weight phostensin is present in human peripheral blood mononuclear cells and many leukemic cell lines. Phostensin is a protein phosphatase-1(PP1) binding protein. It also contains one actin-binding motif at its C-terminal region and binds to the pointed ends of actin filaments, modulating actin dynamics. In the current study, a high-molecular-weight phostensin is identified by using immunoprecipitationin combination with a proteomic approach. This new species of phostensin is also encoded by KIAA1949 and consists of 613 amino acids with an apparent molecular weight of 110 kDa on SDS-PAGE. The low-molecular-weight and high-molecular-weight phostensins were named as phostensin-α and phostensin-β, respectively. Although phostensin-α is the C-terminal region of phostensin-β, it is not degraded from phostensin-β. Phostensin-β is capable of associating with PP1 and actin filaments, and is present in many cell lines.
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Affiliation(s)
- Yu-Shan Lin
- Department of Life Science and Institute of Molecular Biology, National Chung Cheng University, Chia-Yi 62102, Taiwan.
| | - Hsien-Lu Huang
- Department of Life Science and Institute of Molecular Biology, National Chung Cheng University, Chia-Yi 62102, Taiwan.
| | - Wei-Ting Liu
- Department of Life Science and Institute of Molecular Biology, National Chung Cheng University, Chia-Yi 62102, Taiwan.
| | - Ta-Hsien Lin
- Department of Life Science and Institute of Molecular Biology, National Chung Cheng University, Chia-Yi 62102, Taiwan.
| | - Hsien-Bin Huang
- Department of Life Science and Institute of Molecular Biology, National Chung Cheng University, Chia-Yi 62102, Taiwan.
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Salles FT, Andrade LR, Tanda S, Grati M, Plona KL, Gagnon LH, Johnson KR, Kachar B, Berryman MA. CLIC5 stabilizes membrane-actin filament linkages at the base of hair cell stereocilia in a molecular complex with radixin, taperin, and myosin VI. Cytoskeleton (Hoboken) 2013; 71:61-78. [PMID: 24285636 DOI: 10.1002/cm.21159] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Revised: 11/22/2013] [Accepted: 11/25/2013] [Indexed: 12/30/2022]
Abstract
Chloride intracellular channel 5 protein (CLIC5) was originally isolated from microvilli in complex with actin binding proteins including ezrin, a member of the Ezrin-Radixin-Moesin (ERM) family of membrane-cytoskeletal linkers. CLIC5 concentrates at the base of hair cell stereocilia and is required for normal hearing and balance in mice, but its functional significance is poorly understood. This study investigated the role of CLIC5 in postnatal development and maintenance of hair bundles. Confocal and scanning electron microscopy of CLIC5-deficient jitterbug (jbg) mice revealed progressive fusion of stereocilia as early as postnatal day 10. Radixin (RDX), protein tyrosine phosphatase receptor Q (PTPRQ), and taperin (TPRN), deafness-associated proteins that also concentrate at the base of stereocilia, were mislocalized in fused stereocilia of jbg mice. TPRQ and RDX were dispersed even prior to stereocilia fusion. Biochemical assays showed interaction of CLIC5 with ERM proteins, TPRN, and possibly myosin VI (MYO6). In addition, CLIC5 and RDX failed to localize normally in fused stereocilia of MYO6 mutant mice. Based on these findings, we propose a model in which these proteins work together as a complex to stabilize linkages between the plasma membrane and subjacent actin cytoskeleton at the base of stereocilia.
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Affiliation(s)
- Felipe T Salles
- Laboratory of Cell Structure and Dynamics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland
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