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Fontelonga T, Hall AJ, Brown JL, Jung YL, Alexander MS, Dominov JA, Mouly V, Vieira N, Zatz M, Vainzof M, Gussoni E. Tetraspanin CD82 Associates with Trafficking Vesicle in Muscle Cells and Binds to Dysferlin and Myoferlin. Adv Biol (Weinh) 2023; 7:e2300157. [PMID: 37434585 PMCID: PMC10784410 DOI: 10.1002/adbi.202300157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 06/26/2023] [Indexed: 07/13/2023]
Abstract
Tetraspanins organize protein complexes at the cell membrane and are responsible for assembling diverse binding partners in changing cellular states. Tetraspanin CD82 is a useful cell surface marker for prospective isolation of human myogenic progenitors and its expression is decreased in Duchenne muscular dystrophy (DMD) cell lines. The function of CD82 in skeletal muscle remains elusive, partly because the binding partners of this tetraspanin in muscle cells have not been identified. CD82-associated proteins are sought to be identified in human myotubes via mass spectrometry proteomics, which identifies dysferlin and myoferlin as CD82-binding partners. In human dysferlinopathy (Limb girdle muscular dystrophy R2, LGMDR2) myogenic cell lines, expression of CD82 protein is near absent in two of four patient samples. In the cell lines where CD82 protein levels are unaffected, increased expression of the ≈72 kDa mini-dysferlin product is identified using an antibody recognizing the dysferlin C-terminus. These data demonstrate that CD82 binds dysferlin/myoferlin in differentiating muscle cells and its expression can be affected by loss of dysferlin in human myogenic cells.
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Affiliation(s)
| | - Arielle J. Hall
- Division of Genetics and Genomics, Boston Children’s Hospital, MA, USA
| | - Jaedon L. Brown
- Division of Genetics and Genomics, Boston Children’s Hospital, MA, USA
| | - Youngsook L. Jung
- Division of Genetics and Genomics, Boston Children’s Hospital, MA, USA
| | - Matthew S. Alexander
- Department of Pediatrics, Division of Neurology at Children’s of Alabama, University of Alabama at Birmingham, Birmingham, AL, USA
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Janice A. Dominov
- Department of Neurology, University of Massachusetts Worcester, MA, USA
| | | | | | - Mayana Zatz
- Human Genome and Stem Cells Research Center, Biosciences Institute, University of São Paulo, São Paulo, BR
| | - Mariz Vainzof
- Human Genome and Stem Cells Research Center, Biosciences Institute, University of São Paulo, São Paulo, BR
| | - Emanuela Gussoni
- Division of Genetics and Genomics, Boston Children’s Hospital, MA, USA
- The Stem Cell Program, Boston Children’s Hospital, Boston, MA, USA
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Kim JS, Kim HK, Lee J, Jang S, Cho E, Mun SJ, Yoon S, Yang CS. Inhibition of CD82 improves colitis by increasing NLRP3 deubiquitination by BRCC3. Cell Mol Immunol 2023; 20:189-200. [PMID: 36600050 PMCID: PMC9887069 DOI: 10.1038/s41423-022-00971-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 12/21/2022] [Indexed: 01/06/2023] Open
Abstract
CD82 is a transmembrane protein that is involved in cancer suppression and activates immune cells; however, information on the NLRP3 inflammasome is limited. Herein, we show that although CD82 suppressed the activation of the NLRP3 inflammasome in vivo and in vitro, CD82 deficiency decreased the severity of colitis in mice. Furthermore, two binding partners of CD82, NLRP3 and BRCC3, were identified. CD82 binding to these partners increased the degradation of NLRP3 by blocking BRCC3-dependent K63-specific deubiquitination. Previous studies have shown that CD82-specific bacteria in the colon microbiota called Bacteroides vulgatus (B. vulgatus) regulated the expression of CD82 and promoted the activation of the NLRP3 inflammasome. Accordingly, we observed that B. vulgatus administration increased mouse survival by mediating CD82 expression and activating NLRP3 in mice with colitis. Overall, this study showed that CD82 suppression reduced the pathogenesis of colitis by elevating the activation of the NLRP3 inflammasome through BRCC3-dependent K63 deubiquitination. Based on our findings, we propose that B. vulgatus is a novel therapeutic candidate for colitis.
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Affiliation(s)
- Jae-Sung Kim
- Department of Bionano Technology, Hanyang University, Seoul, 04673, Korea
- Institute of Natural Science & Technology, Hanyang University, Ansan, 15588, Korea
| | - Hyo Keun Kim
- Department of Molecular and Life Science, Hanyang University, Ansan, 15588, Korea
- Center for Bionano Intelligence Education and Research, Ansan, 15588, Korea
| | - Joongho Lee
- Department of Computer Science, College of SW Convergence, Dankook University, Yongin, 16890, Korea
| | - Sein Jang
- Department of Molecular and Life Science, Hanyang University, Ansan, 15588, Korea
- Center for Bionano Intelligence Education and Research, Ansan, 15588, Korea
| | - Euni Cho
- Department of Bionano Technology, Hanyang University, Seoul, 04673, Korea
- Center for Bionano Intelligence Education and Research, Ansan, 15588, Korea
| | - Seok-Jun Mun
- Department of Bionano Technology, Hanyang University, Seoul, 04673, Korea
- Center for Bionano Intelligence Education and Research, Ansan, 15588, Korea
| | - Seokhyun Yoon
- Department of Electronics & Electrical Engineering, College of Engineering, Dankook University, Yongin, 16890, Korea
| | - Chul-Su Yang
- Department of Molecular and Life Science, Hanyang University, Ansan, 15588, Korea.
- Center for Bionano Intelligence Education and Research, Ansan, 15588, Korea.
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CD151, a novel host factor of nuclear export signaling in influenza virus infection. J Allergy Clin Immunol 2017; 141:1799-1817. [PMID: 29274410 DOI: 10.1016/j.jaci.2017.11.032] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 11/09/2017] [Accepted: 11/23/2017] [Indexed: 11/20/2022]
Abstract
BACKGROUND Despite advances in our understanding of the mechanisms of influenza A virus (IAV) infection, the crucial virus-host interactions during the viral replication cycle still remain incomplete. Tetraspanin CD151 is highly expressed in the human respiratory tract, but its pathological role in IAV infection is unknown. OBJECTIVES We sought to characterize the functional role and mechanisms of action of CD151 in IAV infection of the upper and lower respiratory tracts with H1N1 and H3N2 strains. METHODS We used CD151-null mice in an in vivo model of IAV infection and clinical donor samples of in vitro-differentiated human nasal epithelial cells cultured at air-liquid interface. RESULTS As compared with wild-type infected mice, CD151-null infected mice exhibited a significant reduction in virus titer and improvement in survival that is associated with pronounced host antiviral response and inflammasome activation together with accelerated lung repair. Interestingly, we show that CD151 complexes newly synthesized viral proteins with host nuclear export proteins and stabilizes microtubule complexes, which are key processes necessary for the polarized trafficking of viral progeny to the host plasma membrane for assembly. CONCLUSIONS Our results provide new mechanistic insights into our understanding of IAV infection. We show that CD151 is a critical novel host factor of nuclear export signaling whereby the IAV nuclear export uses it to complement its own nuclear export proteins (a site not targeted by current therapy), making this regulation unique, and holds promise for the development of novel alternative/complementary strategies to reduce IAV severity.
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4
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Grove J, Hu K, Farquhar MJ, Goodall M, Walker L, Jamshad M, Drummer HE, Bill RM, Balfe P, McKeating JA. A new panel of epitope mapped monoclonal antibodies recognising the prototypical tetraspanin CD81. Wellcome Open Res 2017; 2:82. [PMID: 29090272 PMCID: PMC5657224 DOI: 10.12688/wellcomeopenres.12058.1] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/16/2017] [Indexed: 12/26/2022] Open
Abstract
Background: Tetraspanins are small transmembrane proteins, found in all higher eukaryotes, that compartmentalize cellular membranes through interactions with partner proteins. CD81 is a prototypical tetraspanin and contributes to numerous physiological and pathological processes, including acting as a critical entry receptor for hepatitis C virus (HCV). Antibody engagement of tetraspanins can induce a variety of effects, including actin cytoskeletal rearrangements, activation of MAPK-ERK signaling and cell migration. However, the epitope specificity of most anti-tetraspanin antibodies is not known, limiting mechanistic interpretation of these studies. Methods: We generated a panel of monoclonal antibodies (mAbs) specific for CD81 second extracellular domain (EC2) and performed detailed epitope mapping with a panel of CD81 mutants. All mAbs were screened for their ability to inhibit HCV infection and E2-CD81 association. Nanoscale distribution of cell surface CD81 was investigated by scanning electron microscopy. Results: The antibodies were classified in two epitope groups targeting opposing sides of EC2. We observed a wide range of anti-HCV potencies that were independent of their epitope grouping, but associated with their relative affinity for cell-surface expressed CD81. Scanning electron microscopy identified at least two populations of CD81; monodisperse and higher-order assemblies, consistent with tetraspanin-enriched microdomains. Conclusions: These novel antibodies provide well-characterised tools to investigate CD81 function, including HCV entry, and have the potential to provide insights into tetraspanin biology in general.
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Affiliation(s)
- Joe Grove
- Institute of Immunity and Transplantation, Division of Infection and Immunity, , University College London, London, NW3 2PF, UK
| | - Ke Hu
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, B15 2TT, UK
| | - Michelle J. Farquhar
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, B15 2TT, UK
| | - Margaret Goodall
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, B15 2TT, UK
| | - Lucas Walker
- Institute of Immunity and Transplantation, Division of Infection and Immunity, , University College London, London, NW3 2PF, UK
| | - Mohammed Jamshad
- Institute for Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Heidi E. Drummer
- Centre for Biomedical Resear, Burnet Institute, Melbourne, VIC, 3004, Australia
| | - Roslyn M. Bill
- School of Life and Health Sciences, Aston University, Birmingham, B4 7ET, UK
| | - Peter Balfe
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, B15 2TT, UK
| | - Jane A. McKeating
- Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7BN, UK
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McKelvey KJ, Powell KL, Ashton AW, Morris JM, McCracken SA. Exosomes: Mechanisms of Uptake. J Circ Biomark 2015; 4:7. [PMID: 28936243 PMCID: PMC5572985 DOI: 10.5772/61186] [Citation(s) in RCA: 282] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 06/30/2015] [Indexed: 12/21/2022] Open
Abstract
Exosomes are 30–100 nm microvesicles which contain complex cellular signals of RNA, protein and lipids. Because of this, exosomes are implicated as having limitless therapeutic potential for the treatment of cancer, pregnancy complications, infections, and autoimmune diseases. To date we know a considerable amount about exosome biogenesis and secretion, but there is a paucity of data regarding the uptake of exosomes by immune and non-immune cell types (e.g., cancer cells) and the internal signalling pathways by which these exosomes elicit a cellular response. Answering these questions is of paramount importance.
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Affiliation(s)
- Kelly J McKelvey
- Division of Perinatal Medicine, Kolling Institute of Medical Research, University of Sydney at Royal North Shore Hospital, St Leonards, NSW, Australia
| | - Katie L Powell
- Division of Perinatal Medicine, Kolling Institute of Medical Research, University of Sydney at Royal North Shore Hospital, St Leonards, NSW, Australia.,Pathology North, NSW Health Pathology at Royal North Shore Hospital, St Leonards, NSW, Australia
| | - Anthony W Ashton
- Division of Perinatal Medicine, Kolling Institute of Medical Research, University of Sydney at Royal North Shore Hospital, St Leonards, NSW, Australia
| | - Jonathan M Morris
- Division of Perinatal Medicine, Kolling Institute of Medical Research, University of Sydney at Royal North Shore Hospital, St Leonards, NSW, Australia.,Department of Obstetrics and Gynaecology, Royal North Shore Hospital, St Leonards, NSW, Australia
| | - Sharon A McCracken
- Division of Perinatal Medicine, Kolling Institute of Medical Research, University of Sydney at Royal North Shore Hospital, St Leonards, NSW, Australia
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Abstract
A case of a young girl diagnosed with an antibody deficiency syndrome serves to highlight the role of CD81 in B cell biology. Moreover, this case illustrates a fundamental function of the tetraspanin family, namely their association with partner proteins. Characterization of the patient's B cells revealed lack of surface CD19 although both of her CD19 alleles were normal. Further analysis determined that her antibody deficiency syndrome was due to a mutation in the CD81 gene, which did not enable expression of CD19 on the surface of the patient's B cells. Actually, the partnership of CD81 with CD19 and the dependency of CD19 for its trafficking to the cell surface expression were first documented in CD81-deficient mice. CD81 is a widely expressed protein, yet the mutation in the antibody-deficient patient impaired mostly her B cell function. CD81 is required for multiple normal physiological functions, which have been subverted by major human pathogens, such as hepatitis C virus. However, this review will focus on the function of CD81 in cells of the adaptive immune system. Specifically, it will highlight studies focusing on the different roles of CD81 in B and T cells and on its function in B-T cell interactions.
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7
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Gustafson-Wagner E, Stipp CS. The CD9/CD81 tetraspanin complex and tetraspanin CD151 regulate α3β1 integrin-dependent tumor cell behaviors by overlapping but distinct mechanisms. PLoS One 2013; 8:e61834. [PMID: 23613949 PMCID: PMC3629153 DOI: 10.1371/journal.pone.0061834] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Accepted: 03/15/2013] [Indexed: 01/16/2023] Open
Abstract
Integrin α3β1 potently promotes cell motility on its ligands, laminin-332 and laminin-511, and this may help to explain why α3β1 has repeatedly been linked to breast carcinoma progression and metastasis. The pro-migratory functions of α3β1 depend strongly on lateral interactions with cell surface tetraspanin proteins. Tetraspanin CD151 interacts directly with the α3 integrin subunit and links α3β1 integrin to other tetraspanins, including CD9 and CD81. Loss of CD151 disrupts α3β1 association with other tetraspanins and impairs α3β1-dependent motility. However, the extent to which tetraspanins other than CD151 are required for specific α3β1 functions is unclear. To begin to clarify which aspects of α3β1 function require which tetraspanins, we created breast carcinoma cells depleted of both CD9 and CD81 by RNA interference. Silencing both of these closely related tetraspanins was required to uncover their contributions to α3β1 function. We then directly compared our CD9/CD81-silenced cells to CD151-silenced cells. Both CD9/CD81-silenced cells and CD151-silenced cells showed delayed α3β1-dependent cell spreading on laminin-332. Surprisingly, however, once fully spread, CD9/CD81-silenced cells, but not CD151-silenced cells, displayed impaired α3β1-dependent directed motility and altered front-rear cell morphology. Also unexpectedly, the CD9/CD81 complex, but not CD151, was required to promote α3β1 association with PKCα in breast carcinoma cells, and a PKC inhibitor mimicked aspects of the CD9/CD81-silenced cell motility defect. Our data reveal overlapping, but surprisingly distinct contributions of specific tetraspanins to α3β1 integrin function. Importantly, some of CD9/CD81's α3β1 regulatory functions may not require CD9/CD81 to be physically linked to α3β1 by CD151.
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Affiliation(s)
| | - Christopher S. Stipp
- Department of Biology, University of Iowa, Iowa City, Iowa, United States of America
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, United States of America
- Holden Comprehensive Cancer Center, University of Iowa, Iowa City, Iowa, United States of America
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Risinger JI, Custer M, Feigenbaum L, Simpson RM, Hoover SB, Webster JD, Chandramouli GVR, Tessarollo L, Barrett JC. Normal viability of Kai1/Cd82 deficient mice. Mol Carcinog 2013; 53:610-24. [PMID: 23401136 DOI: 10.1002/mc.22009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Revised: 12/12/2012] [Accepted: 01/04/2013] [Indexed: 11/10/2022]
Abstract
The KAI1/CD82 tetraspanin is a widely expressed cell surface molecule thought to organize diverse cellular signaling processes. KAI1/CD82 suppresses metastasis but not tumorigenicity, establishing it as one of a class of metastasis suppressor genes. In order to further assess its functions, we have characterized the phenotypic properties of Kai1/Cd82 deleted mice, including viability, fertility, lymphocyte composition, blood chemistry and tissue histopathology, and of their wild-type and heterozygote littermates. Interestingly, Kai1/Cd82(-/-) showed no obvious genotype associated defects in any of these processes and displayed no genotype associated histopathologic abnormalities after 12 or 18 months of life. Expression profiles of non-immortal, wild-type and Kai1/Cd82(-/-) mouse embryo fibroblast (MEFs) indicated distinct sex-specific and genotype-specific profiles. These data identify 191 and 1,271 differentially expressed transcripts (by twofold at P < 0.01) based on Kai1/CD82 genotype status in female and male MEFs, respectively. Differentially expressed genes in male MEFs were surprisingly enriched for cell division related processes, suggesting that Kai1/Cd82 may functionally affect these processes. This suggests that Kai/Cd82 has an unappreciated role in the early establishment of proliferation and division when challenged with a new environment that might play a role in adaptability to new metastatic sites.
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Affiliation(s)
- John I Risinger
- Department of Obstetrics, Gynecology and Reproductive Biology, Michigan State University College of Human Medicine, Grand Rapids, Michigan; Center for Cancer Research, National Cancer Institute, Bethesda, Maryland
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9
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Liu WM, Zhang F, Moshiach S, Zhou B, Huang C, Srinivasan K, Khurana S, Zheng Y, Lahti JM, Zhang XA. Tetraspanin CD82 inhibits protrusion and retraction in cell movement by attenuating the plasma membrane-dependent actin organization. PLoS One 2012; 7:e51797. [PMID: 23251627 PMCID: PMC3522597 DOI: 10.1371/journal.pone.0051797] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Accepted: 11/12/2012] [Indexed: 11/18/2022] Open
Abstract
To determine how tetraspanin KAI1/CD82, a tumor metastasis suppressor, inhibits cell migration, we assessed which cellular events critical for motility are altered by KAI1/CD82 and how KAI1/CD82 regulates these events. We found that KAI1/CD82-expressing cells typically exhibited elongated cellular tails and diminished lamellipodia. Live imaging demonstrated that the polarized protrusion and retraction of the plasma membrane became deficient upon KAI1/CD82 expression. The deficiency in developing these motility-related cellular events was caused by poor formations of actin cortical network and stress fiber and by aberrant dynamics in actin organization. Rac1 activity was reduced by KAI1/CD82, consistent with the diminution of lamellipodia and actin cortical network; while the growth factor-stimulated RhoA activity was blocked by KAI1/CD82, consistent with the loss of stress fiber and attenuation in cellular retraction. Upon KAI1/CD82 expression, Rac effector cofilin was not enriched at the cell periphery to facilitate lamellipodia formation while Rho kinase exhibited a significantly lower activity leading to less retraction. Phosphatidylinositol 4, 5-biphosphate, which initiates actin polymerization from the plasma membrane, became less detectable at the cell periphery in KAI1/CD82-expressing cells. Moreover, KAI1/CD82-induced phenotypes likely resulted from the suppression of multiple signaling pathways such as integrin and growth factor signaling. In summary, at the cellular level KAI1/CD82 inhibited polarized protrusion and retraction events by disrupting actin reorganization; at the molecular level, KAI1/CD82 deregulated Rac1, RhoA, and their effectors cofilin and Rho kinase by perturbing the plasma membrane lipids.
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Affiliation(s)
- Wei M. Liu
- Vascular Biology and Cancer Centers and Departments of Medicine and Molecular Science, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - Feng Zhang
- Vascular Biology and Cancer Centers and Departments of Medicine and Molecular Science, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - Simon Moshiach
- Department of Genetics and Tumor Cell Biology, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Bin Zhou
- Vascular Biology and Cancer Centers and Departments of Medicine and Molecular Science, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - Chao Huang
- Vascular Biology and Cancer Centers and Departments of Medicine and Molecular Science, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - Kamalakkannan Srinivasan
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - Seema Khurana
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - Yi Zheng
- Division of Experimental Hematology, Cincinnati Children's Hospital, Cincinnati, Ohio, United States of America
| | - Jill M. Lahti
- Department of Genetics and Tumor Cell Biology, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Xin A. Zhang
- Vascular Biology and Cancer Centers and Departments of Medicine and Molecular Science, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
- * E-mail:
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Hoorn TVD, Paul P, Janssen L, Janssen H, Neefjes J. Dynamics within tetraspanin pairs affect MHC class II expression. J Cell Sci 2012; 125:328-39. [PMID: 22302999 DOI: 10.1242/jcs.088047] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Late endosomal multivesicular bodies (MVBs) are complicated organelles with various subdomains located at the limiting membrane and the internal vesicles (ILVs). ILVs accumulate tetraspanins such as CD63 and CD82 that might form protein assemblies, including major histocompatibility complex class II (MHC-II) and its chaperone human leukocyte antigen (HLA)-DM. Here, we studied the effect of four late endosomal tetraspanin proteins on MHC-II expression. Silencing CD9, CD63 and CD81 enhanced MHC-II expression whereas silencing CD82 did not. No effect on peptide loading was observed. Using confocal FRET technology, we measured the dynamics of CD63 and CD82 interaction with MHC-II and its chaperone HLA-DM. CD63-CD82 interactions remained unaltered in the two MVB subdomains whereas the interactions between CD63 or CD82 homologous pairs changed. CD63 stably associated with MHC-II, and CD82 with HLA-DM, on both MVB subdomains whereas the CD82-MHC-II and CD63-HLA-DM interactions changed. These data visualize for the first time the protein dynamics of tetraspanin assemblies in MVB subdomains. CD63, unlike CD82, stably interacts with MHC-II at both MVB subdomains and controls MHC-II expression.
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Affiliation(s)
- Tineke van den Hoorn
- Division of Cell Biology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
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11
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Tsai YC, Weissman AM. Dissecting the diverse functions of the metastasis suppressor CD82/KAI1. FEBS Lett 2011; 585:3166-73. [PMID: 21875585 PMCID: PMC3409691 DOI: 10.1016/j.febslet.2011.08.031] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Revised: 08/19/2011] [Accepted: 08/19/2011] [Indexed: 01/22/2023]
Abstract
The recent identification of metastasis suppressor genes, the products of which inhibit metastasis but not primary tumor growth, distinguishes oncogenic transformation and tumor suppression from a hallmark of malignancy, the ability of cancer cells to invade sites distant from the primary tumor. The metastasis suppressor CD82/KAI1 is a member of the tetraspanin superfamily of glycoproteins. CD82 suppresses metastasis by multiple mechanisms including inhibition of cell motility and invasion, promotion of cell polarity as well as induction of senescence and apoptosis in response to extracellular stimuli. A common feature of these diverse effects is CD82 regulation of membrane organization as well as protein trafficking and interactions, which affects cellular signaling and intercellular communication.
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Affiliation(s)
- Yien Che Tsai
- Laboratory of Protein Dynamics and Signaling, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, United States.
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12
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Interaction between the HTLV-1 envelope and cellular proteins: impact on virus infection and restriction. Future Med Chem 2011; 2:1651-68. [PMID: 21428837 DOI: 10.4155/fmc.10.255] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The first human retrovirus, human T-lymphotropic virus 1 (HTLV-1), was discovered 30 years ago. Despite intensive study, the cell surface molecules involved in virus entry have only been identified over the past few years. Three molecules form the receptor complex for HTLV-1: glucose transporter 1, neuropilin 1 and heparan sulfate proteoglycans. Another molecule on the surface of dendritic cells, DC-SIGN, may play a role in dendritic cell-mediated infection of cells. In addition to the cell surface molecules used for entry, the HTLV-1 envelope interacts with cellular proteins, enabling the virus to traffic by exploiting cellular delivery pathways. To facilitate both these steps, HTLV-1 encodes motifs that mimic cellular binding partners for the trafficking system and ligands for the receptors. Here we review the interactions between the HTLV-1 envelope and cellular proteins.
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Abstract
Membrane fusion underlies such important biological processes as virus entry into host cells, intracellular protein trafficking, fertilization, formation of muscle fibres and bone resorption. In addition, pathologies such as osteoporosis and implant rejection have been attributed to aberrant fusion. Members of the tetraspanin protein superfamily have been ascribed multiple roles in membrane biology, forming extensive lateral associations and regulating the function of effector molecules by clustering them in specific areas of the membrane. The present review aims to summarize the experimental evidence for tetraspanin function in different fusion events and highlight common themes.
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Zevian S, Winterwood NE, Stipp CS. Structure-function analysis of tetraspanin CD151 reveals distinct requirements for tumor cell behaviors mediated by α3β1 versus α6β4 integrin. J Biol Chem 2011; 286:7496-506. [PMID: 21193415 PMCID: PMC3045005 DOI: 10.1074/jbc.m110.173583] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2010] [Revised: 12/02/2010] [Indexed: 12/13/2022] Open
Abstract
The basement membrane protein laminin-332 (laminin-5) mediates both stable cell adhesion and rapid cell migration and thus has the potential to either restrain or promote tumor cell metastasis. The major cellular receptors for laminin-332 are integrin α3β1, which mediates rapid tumor cell migration, and integrin α6β4, which often mediates stable cell attachment. Tetraspanin protein CD151 interacts directly with both α3β1 and α6β4 integrins and with other tetraspanins, thereby promoting α3β1 and α6β4 association with tetraspanin-enriched microdomains on the cell surface. To explore the possibility of selectively modulating tumor cell responses to laminin-332, we re-expressed a series of CD151 mutants in epidermoid carcinoma cells with near total, RNAi-mediated silencing of endogenous CD151. The interactions of CD151 with its integrin partners or its interactions with other tetraspanins were selectively disrupted by specific mutations in the CD151 large extracellular loop (EC2 domain) or in intracellular CD151 palmitoylation sites, respectively. CD151-integrin association and CD151-tetraspanin association were both important for α3β1 integrin-dependent initial adhesion and rapid migration on laminin-332. Remarkably, however, only CD151-integrin association was required for stable, α6β4 integrin-dependent cell attachment on laminin-332. In addition, we found that a QRD amino acid motif in the CD151 EC2 domain, which had been thought to be crucial for CD151-integrin interaction, is not essential for CD151-integrin association or for the ability of CD151 to promote several different integrin functions. These new data suggest potential strategies for selectively modulating migratory cell responses to laminin-332, while leaving stable cell attachment on laminin-332 intact.
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Affiliation(s)
| | | | - Christopher S. Stipp
- From the Departments of Biology and
- Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa 52242
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15
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Hassuna N, Monk PN, Moseley GW, Partridge LJ. Strategies for targeting tetraspanin proteins: potential therapeutic applications in microbial infections. BioDrugs 2010; 23:341-59. [PMID: 19894777 PMCID: PMC7100176 DOI: 10.2165/11315650-000000000-00000] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The identification of novel targets and strategies for therapy of microbial infections is an area of intensive research due to the failure of conventional vaccines or antibiotics to combat both newly emerging diseases (e.g. viruses such as severe acute respiratory syndrome (SARS) and new influenza strains, and antibiotic-resistant bacteria) and entrenched, pandemic diseases exemplified by HIV. One clear approach to this problem is to target processes of the host organism rather than the microbe. Recent data have indicated that members of the tetraspanin superfamily, proteins with a widespread distribution in eukaryotic organisms and 33 members in humans, may provide such an approach. Tetraspanins traverse the membrane four times, but are distinguished from other four-pass membrane proteins by the presence of conserved charged residues in the transmembrane domains and a defining ‘signature’ motif in the larger of the two extracellular domains (the EC2). They characteristically form promiscuous associations with one another and with other membrane proteins and lipids to generate a specialized type of microdomain: the tetraspanin-enriched microdomain (TEM). TEMs are integral to the main role of tetraspanins as ‘molecular organizers’ involved in functions such as membrane trafficking, cell-cell fusion, motility, and signaling. Increasing evidence demonstrates that tetraspanins are used by intracellular pathogens as a means of entering and replicating within human cells. Although previous investigations focused mainly on viruses such as hepatitis C and HIV, it is now becoming clear that other microbes associate with tetraspanins, using TEMs as a ‘gateway’ to infection. In this article we review the properties and functions of tetraspanins/TEMs that are relevant to infective processes and discuss the accumulating evidence that shows how different pathogens exploit these properties in infection and in the pathogenesis of disease. We then investigate the novel and exciting possibilities of targeting tetraspanins for the treatment of infectious disease, using specific antibodies, recombinant EC2 domains, small-molecule mimetics, and small interfering RNA. Such therapies, directed at host-cell molecules, may provide alternative options for combating fast-mutating or newly emerging pathogens, where conventional approaches face difficulties.
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Affiliation(s)
- Noha Hassuna
- Department of Molecular Biology and Biotechnology, Krebs Institute, University of Sheffield, Sheffield, UK
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16
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O'Donnell CD, Shukla D. A novel function of heparan sulfate in the regulation of cell-cell fusion. J Biol Chem 2009; 284:29654-65. [PMID: 19726670 DOI: 10.1074/jbc.m109.037960] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Despite the important contribution of cell-cell fusion in the development and physiology of eukaryotes, little is known about the mechanisms that regulate this process. Our study shows that glycosaminoglycans and more specifically heparan sulfate (HS) expressed on the cell surface and extracellular matrix may act as negative regulator of cell-cell fusion. Using herpes simplex virus type-1 as a tool to enhance cell-cell fusion, we demonstrate that the absence of HS expression on the cell surface results in a significant increase in cell-cell fusion. An identical phenomenon was observed when other viruses or polyethylene glycol was used as fusion enhancer. Cells deficient in HS biosynthesis showed increased activity of two Rho GTPases, RhoA and Cdc42, both of which showed a correlation between increased activity and increased cell-cell fusion. This could serve as a possible explanation as to why HS-deficient cells showed significantly enhanced cell-cell fusion and suggests that HS could regulate fusion via fine tuning of RhoA and Cdc42 activities.
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Affiliation(s)
- Christopher D O'Donnell
- Department of Ophthalmology and Visual Sciences and the Department of Microbiology and Immunology, College of Medicine, University of Illinois, Chicago, Illinois 60612, USA
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17
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Hemler ME. Targeting of tetraspanin proteins--potential benefits and strategies. Nat Rev Drug Discov 2009; 7:747-58. [PMID: 18758472 DOI: 10.1038/nrd2659] [Citation(s) in RCA: 258] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The tetraspanin transmembrane proteins have emerged as key players in malignancy, the immune system, during fertilization and infectious disease processes. Tetraspanins engage in a wide range of specific molecular interactions, occurring through the formation of tetraspanin-enriched microdomains (TEMs). TEMs therefore serve as a starting point for understanding how tetraspanins affect cell signalling, adhesion, morphology, motility, fusion and virus infection. An abundance of recent evidence suggests that targeting tetraspanins, for example, by monoclonal antibodies, soluble large-loop proteins or RNAi technology, should be therapeutically beneficial.
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Affiliation(s)
- Martin E Hemler
- Dana-Farber Cancer Institute, 44 Binney Street, Boston, Massachussetts 02115, USA.
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18
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Bari R, Zhang YH, Zhang F, Wang NX, Stipp CS, Zheng JJ, Zhang XA. Transmembrane interactions are needed for KAI1/CD82-mediated suppression of cancer invasion and metastasis. THE AMERICAN JOURNAL OF PATHOLOGY 2008; 174:647-60. [PMID: 19116362 DOI: 10.2353/ajpath.2009.080685] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In transmembrane (TM) domains, tetraspanin KAI1/CD82 contains an Asn, a Gln, and a Glu polar residue. A mutation of all three polar residues largely disrupts the migration-, invasion-, and metastasis-suppressive activities of KAI1/CD82. Notably, KAI1/CD82 inhibits the formation of microprotrusions and the release of microvesicles, while the mutation disrupts these inhibitions, revealing the connections of microprotrusion and microvesicle to KAI1/CD82 function. The TM polar residues are needed for proper interactions between KAI1/CD82 and tetraspanins CD9 and CD151, which also regulate cell movement, but not for the association between KAI1/CD82 and alpha3beta1 integrin. However, KAI1/CD82 still efficiently inhibits cell migration when either CD9 or CD151 is absent. Hence, KAI1/CD82 interacts with tetraspanin and integrin by different mechanisms and is unlikely to inhibit cell migration through its associated proteins. Moreover, without significantly affecting the glycosylation, homodimerization, and global folding of KAI1/CD82, the TM interactions maintain the conformational stability of KAI1/CD82, evidenced by the facts that the mutant is more sensitive to denaturation and less associable with tetraspanins and supported by the modeling analysis. Thus, the TM interactions mediated by these polar residues determine a conformation either in or near the tightly packed TM region and this conformation and/or its change are needed for the intrinsic activity of KAI1/CD82. In contrast to immense efforts to block the signaling of cancer progression, the perturbation of TM interactions may open a new avenue to prevent cancer invasion and metastasis.
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Affiliation(s)
- Rafijul Bari
- Vascular Biology Center, University of Tennessee Health Science Center, Memphis, TN 38163, USA
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19
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Kovalenko OV, Yang XH, Hemler ME. A novel cysteine cross-linking method reveals a direct association between claudin-1 and tetraspanin CD9. Mol Cell Proteomics 2007; 6:1855-67. [PMID: 17644758 DOI: 10.1074/mcp.m700183-mcp200] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Tetraspanins serve as molecular organizers of multiprotein microdomains in cell membranes. Hence to understand functions of tetraspanin proteins, it is critical to identify laterally interacting partner proteins. Here we used a novel technical approach involving exposure and cross-linking of membrane-proximal cysteines coupled with LC-MS/MS protein identification. In this manner we identified nine potential tetraspanin CD9 partners, including claudin-1. Chemical cross-linking yielded a CD9-claudin-1 heterodimer, thus confirming direct association and adding claudin-1 to the short list of proteins that can directly associate with CD9. Interaction of CD9 (and other tetraspanins) with claudin-1 was supported by subcellular colocalization and was confirmed in multiple cell lines, although other claudins (claudin-2, -3, -4, -5, and -7) associated to a much lesser extent. Moreover claudin-1 was distributed very similarly to CD9 in sucrose gradients and, like CD9, was released from A431 and A549 cells upon cholesterol depletion. These biochemical features of claudin-1 are characteristic of tetraspanin microdomain proteins. Although claudins are major structural components of intercellular tight junctions, CD9-claudin-1 complexes did not reside in tight junctions, and depletion of key tetraspanins (CD9 and CD151) by small interfering RNA had no effect on paracellular permeability. However, tetraspanin depletion did cause a marked decrease in the stability of newly synthesized claudin-1. In conclusion, these results (a) validate a technical approach that appears to be particularly well suited for identifying protein partners directly associated with tetraspanins or with other proteins that contain membrane-proximal cysteines and (b) provide insight into how non-junctional claudins may be regulated in the context of tetraspanin-enriched microdomains.
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Affiliation(s)
- Oleg V Kovalenko
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
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20
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Wang JC, Bégin LR, Bérubé NG, Chevalier S, Aprikian AG, Gourdeau H, Chevrette M. Down-regulation of CD9 expression during prostate carcinoma progression is associated with CD9 mRNA modifications. Clin Cancer Res 2007; 13:2354-61. [PMID: 17406028 DOI: 10.1158/1078-0432.ccr-06-1692] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
PURPOSE Cluster-of-differentiation antigen 9 (CD9) protein, a member of the tetraspanin family, has been implicated in carcinogenesis of various human tumors. Although decreased expression of the CD82 tetraspanin protein, a close CD9 relative, is associated with prostate cancer progression, CD9 expression has not been analyzed in this malignancy. EXPERIMENTAL DESIGN CD9 expression in human prostatic adenocarcinoma was analyzed by immunohistochemistry on 167 primary tumors and 88 lymph node or bone metastases. CD9 cDNA was sequenced from two human prostate cancer cell lines, prostatic adenocarcinoma, high-grade prostatic intraepithelial neoplasia (PIN), and normal prostatic tissues. RESULTS Although CD9 was detected in the epithelium of normal prostatic tissues, reduced or loss of CD9 expression within neoplastic cells was observed in 24% of 107 clinically localized primary adenocarcinomas, 85% of 60 clinically advanced primary adenocarcinomas, 85% of 65 lymph node metastases, and 65% of 23 bone metastases. Difference in CD9 expression between clinically localized and advanced diseases was highly significant (P < 1 x 10(-7)). Whereas there was no alteration of CD9 cDNA in normal tissues, all PC-3-derived cell lines, one PIN, and four prostatic adenocarcinomas harbored deletions in their CD9 cDNAs. Recurring CD9 point mutations were also found in PC-3M-LN4 cells, one PIN, and seven prostatic adenocarcinomas. CONCLUSIONS CD9 expression is significantly reduced and even lost during prostate cancer progression. Moreover, deletions and mutations of the CD9 mRNA may be associated with loss of protein expression observed in tumor cells. Our data suggest that CD9 inactivation may play an important role in prostate cancer progression.
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Affiliation(s)
- Jia-Chi Wang
- McMaster University Medical Centre, Hamilton, Ontario, Canada
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21
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Mazurov D, Heidecker G, Derse D. The inner loop of tetraspanins CD82 and CD81 mediates interactions with human T cell lymphotrophic virus type 1 Gag protein. J Biol Chem 2006; 282:3896-903. [PMID: 17166843 DOI: 10.1074/jbc.m607322200] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The tetraspanin superfamily proteins play important roles in organizing membrane protein complexes, modulating integrin function, and controlling T cell adhesion. Tetraspanins such as CD82 contain two extracellular loops with its N terminus, C terminus, and inner loop exposed to the cytoplasm. The matrix (MA) domain of human T cell lymphotrophic virus, type 1 (HTLV-1), Gag interacts with the cytoplasmic face of the plasma membrane and is concentrated at tetraspanin-enriched microdomains. To understand the basis of this association, we generated site-directed mutations in the various domains of CD82 and used coimmunoprecipitation and colocalization approaches to examine interactions with HTLV-1 MA. The large extracellular loop of CD82, which is important for interactions with integrins, was not required for the association with HTLV-1 MA. The cytoplasmic N terminus and C terminus of CD82 were also dispensable for CD82-MA interactions. In contrast, mutations of conserved amino acids in the inner loop of CD82 or of palmitoylated cysteines that flank the inner loop diminished CD82 association with MA. HTLV-1 MA also interacted with the inner loop of CD81. Thus, association of HTLV-1 Gag with tetraspanin-enriched microdomains is mediated by the inner loops of CD81 and CD82.
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Affiliation(s)
- Dmitriy Mazurov
- HIV Drug Resistance Program, NCI-Frederick, Frederick, Maryland 21702-1201, USA
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22
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Bandyopadhyay S, Zhan R, Chaudhuri A, Watabe M, Pai SK, Hirota S, Hosobe S, Tsukada T, Miura K, Takano Y, Saito K, Pauza ME, Hayashi S, Wang Y, Mohinta S, Mashimo T, Iiizumi M, Furuta E, Watabe K. Interaction of KAI1 on tumor cells with DARC on vascular endothelium leads to metastasis suppression. Nat Med 2006; 12:933-8. [PMID: 16862154 DOI: 10.1038/nm1444] [Citation(s) in RCA: 170] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2006] [Accepted: 06/14/2006] [Indexed: 11/10/2022]
Abstract
CD82, also known as KAI1, was recently identified as a prostate cancer metastasis suppressor gene on human chromosome 11p1.2 (ref. 1). The product of CD82 is KAI1, a 40- to 75-kDa tetraspanin cell-surface protein also known as the leukocyte cell-surface marker CD82 (refs. 1,2). Downregulation of KAI1 has been found to be clinically associated with metastatic progression in a variety of cancers, whereas overexpression of CD82 specifically suppresses tumor metastasis in various animal models. To define the mechanism of action of KAI1, we used a yeast two-hybrid screen and identified an endothelial cell-surface protein, DARC (also known as gp-Fy), as an interacting partner of KAI1. Our results indicate that the cancer cells expressing KAI1 attach to vascular endothelial cells through direct interaction between KAI1 and DARC, and that this interaction leads to inhibition of tumor cell proliferation and induction of senescence by modulating the expression of TBX2 and p21. Furthermore, the metastasis-suppression activity of KAI1 was significantly compromised in DARC knockout mice, whereas KAI1 completely abrogated pulmonary metastasis in wild-type and heterozygous littermates. These results provide direct evidence that DARC is essential for the function of CD82 as a suppressor of metastasis.
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Affiliation(s)
- Sucharita Bandyopadhyay
- Southern Illinois University School of Medicine, Department of Medical Microbiology, Immunology and Cell Biology, 801 N. Rutledge Street, PO Box 19626, Springfield, Illinois 62794-9626, USA
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23
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Winterwood NE, Varzavand A, Meland MN, Ashman LK, Stipp CS. A critical role for tetraspanin CD151 in alpha3beta1 and alpha6beta4 integrin-dependent tumor cell functions on laminin-5. Mol Biol Cell 2006; 17:2707-21. [PMID: 16571677 PMCID: PMC1474805 DOI: 10.1091/mbc.e05-11-1042] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2005] [Revised: 03/09/2006] [Accepted: 03/20/2006] [Indexed: 01/07/2023] Open
Abstract
The basement membrane protein laminin-5 supports tumor cell adhesion and motility and is implicated at multiple steps of the metastatic cascade. Tetraspanin CD151 engages in lateral, cell surface complexes with both of the major laminin-5 receptors, integrins alpha3beta1 and alpha6beta4. To determine the role of CD151 in tumor cell responses to laminin-5, we used retroviral RNA interference to efficiently silence CD151 expression in epidermal carcinoma cells. Near total loss of CD151 had no effect on steady state cell surface expression of alpha3beta1, alpha6beta4, or other integrins with which CD151 associates. However, CD151-silenced carcinoma cells displayed markedly impaired motility on laminin-5, accompanied by unusually persistent lateral and trailing edge adhesive contacts. CD151 silencing disrupted alpha3beta1 integrin association with tetraspanin-enriched microdomains, reduced the bulk detergent extractability of alpha3beta1, and impaired alpha3beta1 internalization in cells migrating on laminin-5. Both alpha3beta1- and alpha6beta4-dependent cell adhesion to laminin-5 were also impaired in CD151-silenced cells. Reexpressing CD151 in CD151-silenced cells reversed the adhesion and motility defects. Finally, loss of CD151 also impaired migration but not adhesion on substrates other than laminin-5. These data show that CD151 plays a critical role in tumor cell responses to laminin-5 and reveal promotion of integrin recycling as a novel potential mechanism whereby CD151 regulates tumor cell migration.
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Affiliation(s)
- Nicole E. Winterwood
- *University of Iowa, Department of Biological Sciences, Iowa City, IA 52240; and
| | - Afshin Varzavand
- *University of Iowa, Department of Biological Sciences, Iowa City, IA 52240; and
| | - Marit N. Meland
- *University of Iowa, Department of Biological Sciences, Iowa City, IA 52240; and
| | - Leonie K. Ashman
- School of Biomedical Sciences, Medical Sciences Building, University of Newcastle, Callaghan NSW 2308, Australia
| | - Christopher S. Stipp
- *University of Iowa, Department of Biological Sciences, Iowa City, IA 52240; and
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24
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Custer MC, Risinger JI, Hoover S, Simpson RM, Patterson T, Barrett JC. Characterization of an antibody that can detect the Kai1/CD82 murine metastasis suppressor. Prostate 2006; 66:567-77. [PMID: 16372335 DOI: 10.1002/pros.20386] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND Kai1, also known as CD82, is a member of the tetraspanin family (TM4SF). The human homolog, KAI1, is an activation antigen of T-cells and is a metastasis suppressor for prostate and other cancers. Little is known about the mouse protein because of the lack of antibody reagents. METHODS Peptide immunized rabbits were used to generate polyclonal antibody to Kai1. The antibody was analyzed using immunoblotting, flow cytometry, and immunohistochemistry. RESULTS This antibody specifically recognizes murine Kai1 protein, crossreacts with rat Kai1 but not with human KAI1. The normal tissue distribution of this protein in mice is shown to be similar to that of the human homolog. Interestingly, mouse prostatic epithelium showed differential expression within the lobes. CONCLUSION This antibody, the first described that can specifically detect murine Kai1/CD82, should be very useful in addressing the mechanism of action of Kai1 in metastatic suppression.
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Affiliation(s)
- Mary C Custer
- Laboratory of Biosystems and Cancer, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.
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25
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Yang XH, Kovalenko OV, Kolesnikova TV, Andzelm MM, Rubinstein E, Strominger JL, Hemler ME. Contrasting effects of EWI proteins, integrins, and protein palmitoylation on cell surface CD9 organization. J Biol Chem 2006; 281:12976-85. [PMID: 16537545 DOI: 10.1074/jbc.m510617200] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
CD9, a tetraspanin protein, makes crucial contributions to sperm egg fusion, other cellular fusions, epidermal growth factor receptor signaling, cell motility, and tumor suppression. Here we characterize a low affinity anti-CD9 antibody, C9BB, which binds preferentially to homoclustered CD9. Using mAb C9BB as a tool, we show that cell surface CD9 homoclustering is promoted by expression of alpha3beta1 and alpha6beta4 integrins and by palmitoylation of the CD9 and beta4 proteins. Conversely, CD9 is shifted toward heteroclusters upon expression of CD9 partner proteins (EWI-2 and EWI-F) or other tetraspanins, or upon ablation of CD9 palmitoylation. Furthermore, unpalmitoylated CD9 showed enhanced EWI-2 association, thereby demonstrating a previously unappreciated role for tetraspanin palmitoylation, and underscoring how depalmitoylation and EWI-2 association may collaborate to shift CD9 from homo- to heteroclusters. In conclusion, we have used a novel molecular probe (mAb C9BB) to demonstrate the existence of multiple types of CD9 complex on the cell surface. A shift from homo- to heteroclustered CD9 may be functionally significant because the latter was especially obvious on malignant epithelial tumor cells. Hence, because of its specialized properties, C9BB may be more useful than other anti-CD9 antibodies for monitoring CD9 during tumor progression.
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Affiliation(s)
- Xiuwei H Yang
- Dana-Farber Cancer Institute and Department of Pathology, Harvard Medical School, Boston, Massachusetts 02115, USA
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26
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Xie L, Green PL. Envelope is a major viral determinant of the distinct in vitro cellular transformation tropism of human T-cell leukemia virus type 1 (HTLV-1) and HTLV-2. J Virol 2006; 79:14536-45. [PMID: 16282453 PMCID: PMC1287554 DOI: 10.1128/jvi.79.23.14536-14545.2005] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Human T-cell leukemia virus type 1 (HTLV-1) and HTLV-2 are related deltaretroviruses but are distinct in their disease-inducing capacity. These viruses can infect a variety of cell types, but only T lymphocytes become transformed, which is defined in vitro as showing indefinite interleukin-2-independent growth. Studies have indicated that HTLV-1 has a preferential tropism for CD4+ T cells in vivo and is associated with the development of leukemia and neurological disease. Conversely, the in vivo T-cell tropism of HTLV-2 is less clear, although it appears that CD8+ T cells preferentially harbor the provirus, with only a few cases of disease association. The difference in T-cell transformation tropism has been confirmed in vitro as shown by the preferential transformation of CD4+ T cells by HTLV-1 versus the transformation of CD8+ T cells by HTLV-2. Our previous studies showed that Tax and overlapping Rex do not confer the distinct T-cell transformation tropisms between HTLV-1 and HTLV-2. Therefore, for this study HTLV-1 and HTLV-2 recombinants were generated to assess the contribution of LTR and env sequences in T-cell transformation tropism. Both sets of proviral recombinants expressed p19 Gag following transfection into cells. Furthermore, recombinant viruses were replication competent and had the capacity to transform T lymphocytes. Our data showed that exchange of the env gene resulted in altered T-cell transformation tropism compared to wild-type virus, while exchange of long terminal repeat sequences had no significant effect. HTLV-2/Env1 preferentially transformed CD4+ T cells similarly to wild-type HTLV-1 (wtHTLV-1), whereas HTLV-1/Env2 had a transformation tropism similar to that of wtHTLV-2 (CD8+ T cells). These results indicate that env is a major viral determinant for HTLV T-cell transformation tropism in vitro and provides strong evidence implicating its contribution to the distinct pathogenesis resulting from HTLV-1 versus HTLV-2 infections.
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Affiliation(s)
- Li Xie
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA
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27
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Liu WM, Zhang XA. KAI1/CD82, a tumor metastasis suppressor. Cancer Lett 2005; 240:183-94. [PMID: 16260083 DOI: 10.1016/j.canlet.2005.08.018] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2005] [Accepted: 08/31/2005] [Indexed: 12/29/2022]
Abstract
Tetraspanin KAI1/CD82 is a wide-spectrum tumor metastasis suppressor. KAI1/CD82 suppresses tumor metastasis by primarily inhibiting cancer cell motility and invasiveness. In tetraspanin-enriched microdomain, KAI1/CD82 associates with the proteins important for cell migration such as cell adhesion molecule, growth factor receptor, and signaling molecule. Likely, KAI1/CD82 down-regulates the functions of these motility-related proteins to inhibit cell migration. The loss of KAI1/CD82 expression in invasive and metastatic cancers is due to a complex, epigenetic mechanism that probably involves transcription factors such as NFkappaB, p53, and beta-catenin.
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Affiliation(s)
- Wei M Liu
- Vascular Biology Center and Department of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA
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28
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Martin F, Roth DM, Jans DA, Pouton CW, Partridge LJ, Monk PN, Moseley GW. Tetraspanins in viral infections: a fundamental role in viral biology? J Virol 2005; 79:10839-51. [PMID: 16103137 PMCID: PMC1193642 DOI: 10.1128/jvi.79.17.10839-10851.2005] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Affiliation(s)
- F Martin
- Academic Neurology Unit, Division of Genomic Medicine, University of Sheffield, UK
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29
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He B, Liu L, Cook GA, Grgurevich S, Jennings LK, Zhang XA. Tetraspanin CD82 Attenuates Cellular Morphogenesis through Down-regulating Integrin α6-Mediated Cell Adhesion. J Biol Chem 2005; 280:3346-54. [PMID: 15557282 DOI: 10.1074/jbc.m406680200] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Tetraspanin CD82 has been implicated in integrin-mediated functions such as cell motility and invasiveness. Although tetraspanins associate with integrins, it is unknown if and how CD82 regulates the functionality of integrins. In this study, we found that Du145 prostate cancer cells underwent morphogenesis on the reconstituted basement membrane Matrigel to form an anastomosing network of multicellular structures. This process entirely depends on integrin alpha6, a receptor for laminin. After CD82 is expressed in Du145 cells, this cellular morphogenesis was abolished, indicating a functional cross-talk between CD82 and alpha6 integrins. Interestingly, antibodies against other tetraspanins expressed in Du145 cells such as CD9, CD81, and CD151 did not block this integrin alpha6-dependent morphogenesis. We further found that CD82 significantly inhibited cell adhesion on laminin 1. Notably, the level of alpha6 integrins on the cell surface was down-regulated upon CD82 expression, although total cellular alpha6 protein levels remained unchanged in CD82-expressing cells. This down-regulation indicates that the diminished cell adhesiveness of CD82-expressing Du145 cells on laminin likely resulted from less cell surface expression of alpha6 integrins. As expected, CD82 physically associated with the integrin alpha6 in Du145-CD82 transfectant cells, suggesting that the formation of the CD82-integrin alpha6 complex reduces alpha6 integrin cell surface expression. Finally, the internalization of cell surface integrin alpha6 is significantly enhanced upon CD82 expression. In conclusion, our results indicate that 1) CD82 attenuates integrin alpha6 signaling during a cellular morphogenic process; 2) the decreased surface expression of alpha6 integrins in CD82-expressing cells is likely responsible for the diminished adhesiveness on laminin and, subsequently, results in the attenuation of alpha6 integrin-mediated cellular morphogenesis; and 3) the accelerated internalization of integrin alpha6 upon CD82 expression correlates with the down-regulation of cell surface integrin alpha6.
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Affiliation(s)
- Bo He
- Vascular Biology Center and Department of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee 38163, USA
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30
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Zhou B, Liu L, Reddivari M, Zhang XA. The palmitoylation of metastasis suppressor KAI1/CD82 is important for its motility- and invasiveness-inhibitory activity. Cancer Res 2004; 64:7455-63. [PMID: 15492270 DOI: 10.1158/0008-5472.can-04-1574] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The cancer metastasis suppressor protein KAI1/CD82 is a member of the tetraspanin superfamily. Recent studies have demonstrated that tetraspanins are palmitoylated and that palmitoylation contributes to the organization of tetraspanin webs or tetraspanin-enriched microdomains. However, the effect of palmitoylation on tetraspanin-mediated cellular functions remains obscure. In this study, we found that tetraspanin KAI1/CD82 was palmitoylated when expressed in PC3 metastatic prostate cancer cells and that palmitoylation involved all of the cytoplasmic cysteine residues proximal to the plasma membrane. Notably, the palmitoylation-deficient KAI1/CD82 mutant largely reversed the wild-type KAI1/CD82's inhibitory effects on migration and invasion of PC3 cells. Also, palmitoylation regulates the subcellular distribution of KAI1/CD82 and its association with other tetraspanins, suggesting that the localized interaction of KAI1/CD82 with tetraspanin webs or tetraspanin-enriched microdomains is important for KAI1/CD82's motility-inhibitory activity. Moreover, we found that KAI1/CD82 palmitoylation affected motility-related subcellular events such as lamellipodia formation and actin cytoskeleton organization and that the alteration of these processes likely contributes to KAI1/CD82's inhibition of motility. Finally, the reversal of cell motility seen in the palmitoylation-deficient KAI1/CD82 mutant correlates with regaining of p130(CAS)-CrkII coupling, a signaling step important for KAI1/CD82's activity. Taken together, our results indicate that palmitoylation is crucial for the functional integrity of tetraspanin KAI1/CD82 during the suppression of cancer cell migration and invasion.
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Affiliation(s)
- Bin Zhou
- Vascular Biology Center and Department of Medicine and Department of Molecular Science, University of Tennessee Health Science Center, Memphis, Tennessee, USA
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31
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Su JS, Arima K, Hasegawa M, Franco OE, Umeda Y, Yanagawa M, Sugimura Y, Kawamura J. Decreased expression of KAI1 metastasis suppressor gene is a recurrence predictor in primary pTa and pT1 urothelial bladder carcinoma. Int J Urol 2004; 11:74-82. [PMID: 14706010 DOI: 10.1111/j.1442-2042.2004.00752.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To examine the expression of the KAI1 metastasis suppressor gene and to evaluate its relationship with tumor recurrence in primary pTa and pT1 urothelial bladder carcinoma. METHODS Samples were obtained from 87 patients after transurethral resection (TUR). Tumor stage and grade were reviewed in 33 patients with pTa and in 54 patients with pT1, with a mean follow-up time of 47.4 +/- 30.1 months. The KAI1 protein immunohistochemical assay was performed. Prognosis was analyzed using the Kaplan-Meier method and Cox's proportional hazards model. Correlation between KAI1 expression and recurrence according to each clinicopathological factor was comparatively evaluated using the chi-squared test. RESULTS Decreased expression of KAI1 protein failed to reach statistical significance for stage (P = 0.25) or morphology of tumor stem (P = 0.19), but it was significantly related to tumor size (P = 0.016). The recurrence-free 5-year survival rates of the group with decreased KAI1 expression was 69.7%, which was significantly higher than the 22.2% for the KAI1-positive group (P < 0.0001). In univariate and multivariate analyses, decreased expression of KAI1 protein, stage pT1, tumor size >3 cm and sessile tumors were independent prognosis factors of recurrence. Despite the lower recurrence rate expected by considering only the clinicopathological factors, decreased KAI1 expression was able to identify the group with a high risk of recurrence. CONCLUSIONS Downregulated KAI1 expression in bladder tumors tends to relate to stage and morphology of the tumor stem and was significantly correlated to tumor size. Decreased expression of KAI1 was associated with the degree of invasiveness and progression of the cancer and was an independent prognostic factor of recurrence in primary pTa and pT1 urothelial bladder carcinoma.
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Affiliation(s)
- Jing-shi Su
- Department of Urology, Faculty of Medicine, Mie University, Tsu, Mie, Japan.
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32
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Little KD, Hemler ME, Stipp CS. Dynamic regulation of a GPCR-tetraspanin-G protein complex on intact cells: central role of CD81 in facilitating GPR56-Galpha q/11 association. Mol Biol Cell 2004; 15:2375-87. [PMID: 15004227 PMCID: PMC404030 DOI: 10.1091/mbc.e03-12-0886] [Citation(s) in RCA: 154] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
By means of a variety of intracellular scaffolding proteins, a vast number of heterotrimeric G protein-coupled receptors (GPCRs) may achieve specificity in signaling through a much smaller number of heterotrimeric G proteins. Members of the tetraspanin family organize extensive complexes of cell surface proteins and thus have the potential to act as GPCR scaffolds; however, tetraspanin-GPCR complexes had not previously been described. We now show that a GPCR, GPR56/TM7XN1, and heterotrimeric G protein subunits, Galpha(q), Galpha(11), and Gbeta, associate specifically with tetraspanins and CD81, but not with other tetraspanins. CD9 Complexes of GPR56 with CD9 and CD81 remained intact when fully solubilized and were resistant to cholesterol depletion. Hence they do not depend on detergent-insoluble, raft-like membrane microdomains for stability. A central role for CD81 in promoting or stabilizing a GPR56-CD81-Galpha(q/11) complex was revealed by CD81 immunodepletion and reexpression experiments. Finally, antibody engagement of cell surface CD81 or cell activation with phorbol ester revealed two distinct mechanisms by which GPR56-CD81-Galpha(q/11) complexes can be dynamically regulated. These data reveal a potential role for tetraspanins CD9 and CD81 as GPCR scaffolding proteins.
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Affiliation(s)
- Kevin D Little
- Dana-Farber Cancer Institute and Department of Pathology, Harvard Medical School, Boston, MA 02115, USA
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33
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Abstract
Recent years have seen much excitement over the possibility that adult mammalian stem cells may be capable of differentiating across tissue lineage boundaries, and as such may represent novel, accessible, and very versatile effectors of therapeutic tissue regeneration. Yet studies proposing such "plasticity" of adult somatic stem cells remain controversial, and in general, existing evidence suggests that in vivo such unexpected transformations are exceedingly rare and in some cases can be accounted for by equally unexpected alternative explanations.
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Affiliation(s)
- Amy J Wagers
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA.
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34
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Hemler ME. Tetraspanin proteins mediate cellular penetration, invasion, and fusion events and define a novel type of membrane microdomain. Annu Rev Cell Dev Biol 2004; 19:397-422. [PMID: 14570575 DOI: 10.1146/annurev.cellbio.19.111301.153609] [Citation(s) in RCA: 639] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
This review summarizes key aspects of tetraspanin proteins, with a focus on the functional relevance and structural features of these proteins and how they are organized into a novel type of membrane microdomain. Despite the size of the tetraspanin family and their abundance and wide distribution over many cell types, most have not been studied. However, from studies of prototype tetraspanins, information regarding functions, cell biology, and structural organization has begun to emerge. Genetic evidence points to critical roles for tetraspanins on oocytes during fertilization, in fungi during leaf invasion, in Drosophila embryos during neuromuscular synapse formation, during T and B lymphocyte activation, in brain function, and in retinal degeneration. From structure and mutagenesis studies, we are beginning to understand functional subregions within tetraspanins, as well as the levels of connections among tetraspanins and their many associated proteins. Tetraspanin-enriched microdomains (TEMs) are emerging as entities physically and functionally distinct from lipid rafts. These microdomains now provide a context in which to evaluate tetraspanins in the regulation of growth factor signaling and in the modulation of integrin-mediated post-cell adhesion events. Finally, the enrichment of tetraspanins within secreted vesicles called exosomes, coupled with hints that tetraspanins may regulate vesicle fusion and/or fission, suggests exciting new directions for future research.
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Affiliation(s)
- Martin E Hemler
- Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA.
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35
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Kovalenko OV, Yang X, Kolesnikova TV, Hemler ME. Evidence for specific tetraspanin homodimers: inhibition of palmitoylation makes cysteine residues available for cross-linking. Biochem J 2004; 377:407-17. [PMID: 14556650 PMCID: PMC1223880 DOI: 10.1042/bj20031037] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2003] [Revised: 10/01/2003] [Accepted: 10/14/2003] [Indexed: 11/17/2022]
Abstract
It is a well-established fact that tetraspanin proteins, a large family of integral membrane proteins involved in cell motility, fusion and signalling, associate extensively with one another and with other transmembrane and membrane-proximal proteins. In this study, we present results strongly suggesting that tetraspanin homodimers are fundamental units within larger tetraspanin complexes. Evidence for constitutive CD9 homodimers was obtained using several cell lines, utilizing the following four methods: (1) spontaneous cross-linking via intermolecular disulphide bonds, (2) use of a cysteine-reactive covalent cross-linking agent, (3) use of an amino-reactive covalent cross-linking agent, and (4) covalent cross-linking via direct intermolecular disulphide bridging between unpalmitoylated membrane-proximal cysteine residues. In the last case, incubation of cells with the palmitoylation inhibitor 2-bromopalmitate exposed membrane-proximal cysteine residues, thus effectively promoting 'zero-length' cross-linking to stabilize homodimers. Similar to CD9, other tetraspanins (CD81 and CD151) also showed a tendency to homodimerize. Tetraspanin homodimers were assembled from newly synthesized proteins in the Golgi, as evidenced by cycloheximide and Brefeldin A inhibition studies. Importantly, tetraspanin homodimers appeared on the cell surface and participated in typical 'tetraspanin web' interactions with other proteins. Whereas homodimers were the predominant cross-linked species, we also observed some higher-order complexes (trimers, tetramers or higher) and a much lower level of cross-linking between different tetraspanins (CD81-CD9, CD9-CD151, CD81-CD151). In conclusion, our results strongly suggest that tetraspanin homodimers, formed in the Golgi and present at the cell surface, serve as building blocks for the assembly of larger, multicomponent tetraspanin protein complexes.
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Affiliation(s)
- Oleg V Kovalenko
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute and Department of Pathology, Harvard Medical School, Boston, MA 02115, USA
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36
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Kolesnikova TV, Stipp CS, Rao RM, Lane WS, Luscinskas FW, Hemler ME. EWI-2 modulates lymphocyte integrin alpha4beta1 functions. Blood 2003; 103:3013-9. [PMID: 15070678 DOI: 10.1182/blood-2003-07-2201] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The most prominent cell-surface integrin alpha4beta1 partner, a 70-kDa protein, was isolated from MOLT-4 T leukemia cells, using anti-alpha4beta1 integrin antibody-coated beads. By mass spectrometry, this protein was identified as EWI-2, a previously described cell-surface partner for tetraspanin proteins CD9 and CD81. Wild-type EWI-2 overexpression had no effect on MOLT-4 cell tethering and adhesion strengthening on the alpha4beta1 ligand, vascular cell adhesion molecule-1 (VCAM-1), in shear flow assays. However, EWI-2 markedly impaired spreading and ruffling on VCAM-1. In contrast, a mutant EWI-2 molecule, with a different cytoplasmic tail, neither impaired cell spreading nor associated with alpha4beta1 and CD81. The endogenous wild-type EWI-2-CD81-alpha4beta1 complex was fully soluble, and highly specific as seen by the absence of other MOLT-4 cell-surface proteins. Also, it was relatively small in size (0.5 x 10(6) Da to 4 x 10(6) Da), as estimated by size exclusion chromatography. Overexpression of EWI-2 in MOLT-4 cells caused reorganization of cell-surface CD81, increased the extent of CD81-CD81, CD81-alpha4beta1, and alpha4beta1-alpha4beta1 associations, and increased the apparent size of CD81-alpha4beta1 complexes. We suggest that EWI-2-dependent reorganization of alpha4beta1-CD81 complexes on the cell surface is responsible for EWI-2 effects on integrin-dependent morphology and motility functions.
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Affiliation(s)
- Tatiana V Kolesnikova
- Dana-Farber Cancer Institute, Brigham and Women's Hospital, Department of Pathology, Harvard Medical School, Boston, MA 02115, USA
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37
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Zhang XA, He B, Zhou B, Liu L. Requirement of the p130CAS-Crk coupling for metastasis suppressor KAI1/CD82-mediated inhibition of cell migration. J Biol Chem 2003; 278:27319-28. [PMID: 12738793 DOI: 10.1074/jbc.m303039200] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
KAI1/CD82 protein is a member of the tetraspanin superfamily and has been rediscovered as a cancer metastasis suppressor. The mechanism of KAI1/CD82-mediated suppression of cancer metastasis remains to be established. In this study, we found that migration of the metastatic prostate cancer cell line Du145 was substantially inhibited when KAI1/CD82 was expressed. The expression of focal adhesion kinase (FAK) and Lyn, a Src family tyrosine kinase and substrate of FAK, was up-regulated at both RNA and protein levels upon KAI1/CD82 expression. The activation of FAK and Lyn, however, remained unchanged in Du145-KAI1/CD82 cells. As a downstream target of FAK-Lyn signaling, the p130CAS (Crk-associated substrate) protein was decreased upon the expression of KAI1/CD82. Consequently, less p130CAS-CrkII complex, which functions as a "molecular switch" in cell motility, was formed in Du145-KAI1/CD82 cells. To confirm that the p130CAS-CrkII complex is indeed important for the motility inhibition by KAI1/CD82, overexpression of p130CAS in Du145-KAI1/CD82 cells increased the formation of p130CAS-CrkII complex and largely reversed the KAI1/CD82-mediated inhibition of cell motility. Taken together, our studies indicate the following: 1) signaling of FAK-Lyn-p130CAS-CrkII pathway is altered in KAI1/CD82-expressing cells, and 2) p130CAS-CrkII coupling is required for KAI1/CD82-mediated suppression of cell motility.
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Affiliation(s)
- Xin A Zhang
- Vascular Biology Center and Department of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee 38163, USA.
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38
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Takeda Y, Tachibana I, Miyado K, Kobayashi M, Miyazaki T, Funakoshi T, Kimura H, Yamane H, Saito Y, Goto H, Yoneda T, Yoshida M, Kumagai T, Osaki T, Hayashi S, Kawase I, Mekada E. Tetraspanins CD9 and CD81 function to prevent the fusion of mononuclear phagocytes. J Cell Biol 2003; 161:945-56. [PMID: 12796480 PMCID: PMC2172976 DOI: 10.1083/jcb.200212031] [Citation(s) in RCA: 150] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Tetraspanins CD9 and CD81 facilitate the fusion between gametes, myoblasts, or virus-infected cells. Here, we investigated the role of these tetraspanins in the fusion of mononuclear phagocytes. Expression of CD9 and CD81 and their complex formation with integrins were up-regulated when blood monocytes were cultured under normal conditions. Under fusogenic conditions in the presence of Con A, CD9 and CD81 up-regulation was inhibited, and their complex formation with integrins was down-regulated. Anti-CD9 and -CD81 antibodies, which were previously shown to inhibit the fusion of gametes, myoblasts, and virus-infected cells, unexpectedly promoted the fusion of monocytes and alveolar macrophages. However, these effects were not due to altered cell adhesion, aggregation, or cytokine production. When stimulated in vitro or in vivo, alveolar macrophages and bone marrow cells of CD9- and CD81-null mice formed larger numbers of multinucleated cells than those of wild-type mice. Finally, CD9/CD81 double-null mice spontaneously developed multinucleated giant cells in the lung and showed enhanced osteoclastogenesis in the bone. These results suggest that CD9 and CD81 coordinately prevent the fusion of mononuclear phagocytes.
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Affiliation(s)
- Yoshito Takeda
- Department of Molecular Medicine, Osaka University Graduate School of Medicine, Japan
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39
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von Lindern JJ, Rojo D, Grovit-Ferbas K, Yeramian C, Deng C, Herbein G, Ferguson MR, Pappas TC, Decker JM, Singh A, Collman RG, O'Brien WA. Potential role for CD63 in CCR5-mediated human immunodeficiency virus type 1 infection of macrophages. J Virol 2003; 77:3624-33. [PMID: 12610138 PMCID: PMC149503 DOI: 10.1128/jvi.77.6.3624-3633.2003] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Macrophages and CD4(+) lymphocytes are the principal target cells for human immunodeficiency virus type 1 (HIV-1) infection, but the molecular details of infection may differ between these cell types. During studies to identify cellular molecules that could be involved in macrophage infection, we observed inhibition of HIV-1 infection of macrophages by monoclonal antibody (MAb) to the tetraspan transmembrane glycoprotein CD63. Pretreatment of primary macrophages with anti-CD63 MAb, but not MAbs to other macrophage cell surface tetraspanins (CD9, CD81, and CD82), was shown to inhibit infection by several R5 and dualtropic strains, but not by X4 isolates. The block to productive infection was postfusion, as assessed by macrophage cell-cell fusion assays, but was prior to reverse transcription, as determined by quantitative PCR assay for new viral DNA formation. The inhibitory effects of anti-CD63 in primary macrophages could not be explained by changes in the levels of CD4, CCR5, or beta-chemokines. Infections of peripheral blood lymphocytes and certain cell lines were unaffected by treatment with anti-CD63, suggesting that the role of CD63 in HIV-1 infection may be specific for macrophages.
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Affiliation(s)
- Jana J von Lindern
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas 77555, USA
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40
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Aryee DNT, Ambros I, Ambros PF, Muehlbacher K, Luegmayr A, Yoshie O, Kovar H. Frequent low level expression in Ewing sarcoma family tumors and widespread absence of the metastasis suppressor KAI1/CD82 in neuroblastoma. Pediatr Res 2002; 52:279-85. [PMID: 12149507 DOI: 10.1203/00006450-200208000-00022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The transmembrane 4 superfamily member KAI1/CD82, a metastasis suppressor, is correlated inversely with the progression and invasion of several tumors. It is capable of inhibiting metastasis without affecting tumorigenicity per se. KAI1/CD82 expression is down-regulated in the progression of common solid epithelial tumors of adulthood. Mutation of p53 is suggested to be involved in the modulation of KAI1. As little is known about its expression and possible prognostic impact in pediatric tumors, we investigated KAI1/CD82 expression in cell lines and primary tumor samples from pediatric tumors of neuroectodermal origin, neuroblastoma and Ewing's sarcoma family tumor. Twenty-four of 29 Ewing's sarcoma family tumor cell lines, independent of p53 status, showed KAI1 mRNA positivity by reverse transcription-PCR analysis in contrast to zero of eight neuroblastoma cell lines. Among 13 primary Ewing's sarcoma family tumor samples from patients with different disease extension, KAI1 mRNA expression was low as detected by reverse transcription-PCR. Twenty of 30 primary neuroblastoma specimens were KAI1-negative by immunofluorescence analysis whereas the remaining 10 gave weak to moderate staining patterns. There was no apparent correlation of KAI1 expression with any clinical or genetic features of the patients whose tumor samples were studied. Consequently, KAI1 may not be of prognostic relevance in this group of tumors although there may be some role for KAI1 modulation in the biology of these neuroectodermal tumors.
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Affiliation(s)
- Dave N T Aryee
- Children's Cancer Research Institute (CCRI), St. Anna Kinderspital, A-1090 Vienna, Austria.
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41
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Yang X, Claas C, Kraeft SK, Chen LB, Wang Z, Kreidberg JA, Hemler ME. Palmitoylation of tetraspanin proteins: modulation of CD151 lateral interactions, subcellular distribution, and integrin-dependent cell morphology. Mol Biol Cell 2002; 13:767-81. [PMID: 11907260 PMCID: PMC99597 DOI: 10.1091/mbc.01-05-0275] [Citation(s) in RCA: 188] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Here we demonstrate that multiple tetraspanin (transmembrane 4 superfamily) proteins are palmitoylated, in either the Golgi or a post-Golgi compartment. Using CD151 as a model tetraspanin, we identified and mutated intracellular N-terminal and C-terminal cysteine palmitoylation sites. Simultaneous mutations of C11, C15, C242, and C243 (each to serine) eliminated >90% of CD151 palmitoylation. Notably, palmitoylation had minimal influence on the density of tetraspanin protein complexes, did not promote tetraspanin localization into detergent-resistant microdomains, and was not required for CD151-alpha 3 beta 1 integrin association. However, the CD151 tetra mutant showed markedly diminished associations with other cell surface proteins, including other transmembrane 4 superfamily proteins (CD9, CD63). Thus, palmitoylation may be critical for assembly of the large network of cell surface tetraspanin-protein interactions, sometimes called the "tetraspanin web." Also, compared with wild-type CD151, the tetra mutant was much more diffusely distributed and showed markedly diminished stability during biosynthesis. Finally, expression of the tetra-CD151 mutant profoundly altered alpha 3 integrin-deficient kidney epithelial cells, such that they converted from a dispersed, elongated morphology to an epithelium-like cobblestone clustering. These results point to novel biochemical and biological functions for tetraspanin palmitoylation.
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Affiliation(s)
- Xiuwei Yang
- Dana-Farber Cancer Institute and Department of Pathology, Harvard Medical School, Boston, Massachusetts 02115, USA
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42
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Arihiro K, Inai K. Loss of KAI1/CD82 expression in bone and soft tissue tumors is not associated with lung metastasis. Pathol Res Pract 2002; 197:627-33. [PMID: 11569927 DOI: 10.1078/0344-0338-00137] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The KAI1 gene has been identified as a metastasis suppressor gene in human prostate cancer. Decrease or loss of KAI1/CD82 expression has been shown to be associated with poorer prognosis and metastasis in carcinomas of various organs. The purpose of this study was to examine whether KAI1/CD82 is expressed in bone and soft tissue tumors, and whether it is associated with metastasis to the lungs. Immunohistochemically, KAI1/CD82 expression in benign and malignant soft tissue tumors was noted in 83% and 37% of cases, respectively. KAI1/CD82 was- also expressed in benign bone tumors and osteosarcomas in 67% and 36% of the cases, respectively. Four (40%) of 10 osteosarcoma cases with no lung metastasis and one (25%) of four osteosarcoma cases with lung metastasis were positive for KAI1/CD82, respectively. Metastasis of osteosarcoma cells to the lungs was not correlated with the loss of KAI1/CD82 in osteosarcoma cells.
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Affiliation(s)
- K Arihiro
- Second Department of Pathology, Hiroshima University School of Medicine, Japan
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43
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Kropshofer H, Spindeldreher S, Röhn TA, Platania N, Grygar C, Daniel N, Wölpl A, Langen H, Horejsi V, Vogt AB. Tetraspan microdomains distinct from lipid rafts enrich select peptide-MHC class II complexes. Nat Immunol 2002; 3:61-8. [PMID: 11743588 DOI: 10.1038/ni750] [Citation(s) in RCA: 181] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Complexes of peptide and major histocompatibility complex (MHC) class II are expressed on the surface of antigen-presenting cells but their molecular organization is unknown. Here we show that subsets of MHC class II molecules localize to membrane microdomains together with tetraspan proteins, the peptide editor HLA-DM and the costimulator CD86. Tetraspan microdomains differ from other membrane areas such as lipid rafts, as they enrich MHC class II molecules carrying a selected set of peptide antigens. Antigen-presenting cells deficient in tetraspan microdomains have a reduced capacity to activate CD4+ T cells. Thus, the organization of uniformly loaded peptide-MHC class II complexes in tetraspan domains may be a very early event that determines both the composition of the immunological synapse and the quality of the subsequent T helper cell response.
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MESH Headings
- Amino Acid Sequence
- Antibodies, Monoclonal/immunology
- Antigen Presentation
- Antigens/immunology
- Antigens, CD/immunology
- Antigens, Differentiation, B-Lymphocyte/immunology
- B-Lymphocytes/drug effects
- B-Lymphocytes/immunology
- B7-2 Antigen
- CD4-Positive T-Lymphocytes/immunology
- Cell Communication
- Cell Compartmentation
- Cell Line, Transformed
- Cyclodextrins/pharmacology
- Endosomes/metabolism
- HLA-D Antigens/immunology
- HLA-DP Antigens/immunology
- HLA-DR Antigens/immunology
- Histocompatibility Antigens Class II/immunology
- Humans
- Hybridomas/immunology
- Lipopolysaccharides/pharmacology
- Lymphocyte Activation
- Lysosomes/metabolism
- Macromolecular Substances
- Membrane Glycoproteins/immunology
- Membrane Microdomains/drug effects
- Membrane Microdomains/immunology
- Membrane Proteins/analysis
- Microscopy, Confocal
- Molecular Sequence Data
- Peptide Fragments/immunology
- Receptors, Antigen, T-Cell/immunology
- Saponins/pharmacology
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
- beta-Cyclodextrins
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Affiliation(s)
- H Kropshofer
- Basel Institute for Immunology, 4005 Basel, Switzerland.
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44
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Abstract
The transmembrane proteins of the tetraspanin superfamily are implicated in a diverse range of biological phenomena, including cell motility, metastasis, cell proliferation and differentiation. The tetraspanins are associated with adhesion receptors of the integrin family and regulate integrin-dependent cell migration. In cells attached to the extracellular matrix, the integrin-tetraspanin adhesion complexes are clustered into a distinct type of adhesion structure at the cell periphery. Various tetraspanins are associated with phosphatidylinositol 4-kinase and protein kinase C isoforms, and they may facilitate assembly of signalling complexes by tethering these enzymes to integrin heterodimers. At the plasma membrane, integrin-tetraspanin signalling complexes are partitioned into specific microdomains proximal to cholesterol-rich lipid rafts. A substantial fraction of tetraspanins colocalise with integrins in various intracellular vesicular compartments. It is proposed that tetraspanins can influence cell migration by one of the following mechanisms: (1) modulation of integrin signalling; (2) compartmentalisation of integrins on the cell surface; or (3) direction of intracellular trafficking and recycling of integrins.
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Affiliation(s)
- F Berditchevski
- CRC Institute for Cancer Studies, The University of Birmingham, Edgbaston, Birmingham, B15 2TA, UK.
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45
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Stipp CS, Kolesnikova TV, Hemler ME. EWI-2 is a major CD9 and CD81 partner and member of a novel Ig protein subfamily. J Biol Chem 2001; 276:40545-54. [PMID: 11504738 DOI: 10.1074/jbc.m107338200] [Citation(s) in RCA: 171] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
A novel Ig superfamily protein, EWI-2, was co-purified with tetraspanin protein CD81 under relatively stringent Brij 96 detergent conditions and identified by mass spectrometric protein sequencing. EWI-2 associated specifically with CD9 and CD81 but not with other tetraspanins or with integrins. Immunodepletion experiments indicated that EWI-2-CD9/CD81 interactions are highly stoichiometric, with approximately 70% of CD9 and CD81 associated with EWI-2 in an embryonic kidney cell line. The EWI-2 molecule was covalently cross-linked (in separate complexes) to both CD81 and CD9, suggesting that association is direct. EWI-2 is part of a novel Ig subfamily that includes EWI-F (F2alpha receptor regulatory protein (FPRP), CD9P-1), EWI-3 (IgSF3), and EWI-101 (CD101). All four members of this Ig subfamily contain a Glu-Trp-Ile (EWI) motif not seen in other Ig proteins. As shown previously, the EWI-F molecule likewise forms highly proximal, specific, and stoichiometric complexes with CD9 and CD81. Human and murine EWI-2 protein sequences are 91% identical, and transcripts in the two species are expressed in virtually every tissue tested. Thus, EWI-2 potentially contributes to a variety of CD9 and CD81 functions seen in different cell and tissue types.
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Affiliation(s)
- C S Stipp
- Dana-Farber Cancer Institute and the Department of Pathology, Harvard Medical School, Boston, Mssachusetts 02115, USA
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Schindl M, Birner P, Breitenecker G, Oberhuber G. Downregulation of KAI1 metastasis suppressor protein is associated with a dismal prognosis in epithelial ovarian cancer. Gynecol Oncol 2001; 83:244-8. [PMID: 11606078 DOI: 10.1006/gyno.2001.6366] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJECTIVES The aim of this study was to investigate the impact of downregulation of KAI1 metastasis suppressor protein in epithelial ovarian cancer. In addition, correlation of KAI1 and p53 immunostaining was investigated. METHODS Expression of KAI1 and p53 was immunohistochemically determined in 107 specimens of epithelial ovarian cancer stages I-IV. Survival of patients was investigated using uni- and multivariate analysis. RESULTS Strong KAI1 expression was observed in 17.8% of cases, moderate in 27.1%, weak in 21.5%, and complete loss of KAI1 expression in 33.6%. Overexpression of p53 protein was observed in 45.8%. There was correlation of KAI1 expression neither with p53 expression nor with various clinical and histopathological parameters. Serous ovarian cancers showed significantly decreased staining intensity of KAI when compared to other histological types (P = 0.007). Univariate and multivariate analysis revealed that patients with strong or moderate expression of KAI1 had a significantly longer overall (P = 0.0013) and disease-free survival (P = 0.0048) when compared to those with low or absent expression. CONCLUSION KAI1 downregulation is an independent prognostic factor in epithelial ovarian cancer, indicating dismal prognosis. Our study did not reveal a correlation between p53 status and KAI1 expression, suggesting that p53-independent mechanisms might be involved in the downregulation of KAI1.
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Affiliation(s)
- M Schindl
- Institute of Clinical Pathology, University of Vienna, Vienna, A-1090, Austria
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Seraj MJ, Harding MA, Gildea JJ, Welch DR, Theodorescu D. The relationship of BRMS1 and RhoGDI2 gene expression to metastatic potential in lineage related human bladder cancer cell lines. Clin Exp Metastasis 2001; 18:519-25. [PMID: 11592309 DOI: 10.1023/a:1011819621859] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We have recently characterized a human bladder cancer cell line T24 and a more aggressive lineage related variant of it, T24T. To gain further insights, we have studied their metastatic ability in an in vivo model system. Results show that T24 forms significantly fewer [4/12 (1/11) mice had metastases with 1-2 lesions/mouse] metastasis in SCID/bg mice than T24T [14/14 (6/6) mice had metastases with a mean of 24-28 lesions/mouse]. To begin exploring the mechanisms underlying this difference, we evaluated the mRNA and protein expression levels of metastasis-suppressor genes, known to be important in the progression of other cancers, in our model of bladder cancer progression. A higher mRNA expression of BRMS1, a metastasis suppressor in breast cancer, was observed in T24 cells. In addition, RhoGDI2 mRNA expression was only observed in T24 when compared to T24T, suggesting that Rho activation might play a significant role in the metastatic cascade. However, a basal level mRNA expression of KISS1, described as metastasis suppressor in melanoma and breast, was observed in both the lines and had slightly higher expression in T24T. No difference of Nm23-H1, KAI1, MKK4/SEK1 and E-Cadherin protein levels were noted between these two lines. In summary, it appears that the T24/T24T paired cell lines constitute a useful model for the study of human bladder cancer metastasis that will allow both the discovery and mechanistic evaluation of genes potentially involved in this process.
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Affiliation(s)
- M J Seraj
- Department of Molecular Physiology, University of Virginia, Charlottesville, USA
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Niyogi K, Hildreth JE. Characterization of new syncytium-inhibiting monoclonal antibodies implicates lipid rafts in human T-cell leukemia virus type 1 syncytium formation. J Virol 2001; 75:7351-61. [PMID: 11462007 PMCID: PMC114970 DOI: 10.1128/jvi.75.16.7351-7361.2001] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
We have previously shown that erythroleukemia cells (K562) transfected with vascular adhesion molecule 1 (VCAM-1) are susceptible to human T-cell leukemia virus type 1 (HTLV-1)-induced syncytium formation. Since expression of VCAM-1 alone is not sufficient to render cells susceptible to HTLV-1 fusion, K562 cells appear to express a second molecule critical for HTLV-induced syncytium formation. By immunizing mice with K562 cells, we have isolated four monoclonal antibodies (MAbs), K5.M1, K5.M2, K5.M3, and K5.M4, that inhibit HTLV-induced syncytium formation between infected MT2 cells and susceptible K562/VCAM1 cells. These MAbs recognize distinct proteins on the surface of cells as determined by cell phenotyping, immunoprecipitation, and Western blot analysis. Since three of the proteins recognized by the MAbs appear to be GPI linked, we isolated lipid rafts and determined by immunoblot analysis that all four MAbs recognize proteins that sort entirely or in large part to lipid rafts. Dispersion of lipid rafts on the cells by cholesterol depletion with beta-cyclodextrin resulted in inhibition of syncytium formation, and this effect was not seen when the beta-cyclodextrin was preloaded with cholesterol before treating the cells. The results of these studies suggest that lipid rafts may play an important role in HTLV-1 syncytium formation.
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Affiliation(s)
- K Niyogi
- The Leukocyte Immunochemistry Laboratory, Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 212056, USA
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Zhang XA, Bontrager AL, Hemler ME. Transmembrane-4 superfamily proteins associate with activated protein kinase C (PKC) and link PKC to specific beta(1) integrins. J Biol Chem 2001; 276:25005-13. [PMID: 11325968 DOI: 10.1074/jbc.m102156200] [Citation(s) in RCA: 262] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Translocation of conventional protein kinases C (PKCs) to the plasma membrane leads to their specific association with transmembrane-4 superfamily (TM4SF; tetraspanin) proteins (CD9, CD53, CD81, CD82, and CD151), as demonstrated by reciprocal co-immunoprecipitation and covalent cross-linking experiments. Although formation and maintenance of TM4SF-PKC complexes are not dependent on integrins, TM4SF proteins can act as linker molecules, recruiting PKC into proximity with specific integrins. Previous studies showed that the extracellular large loop of TM4SF proteins determines integrin associations. In contrast, specificity for PKC association probably resides within cytoplasmic tails or the first two transmembrane domains of TM4SF proteins, as seen from studies with chimeric CD9 molecules. Consistent with a TM4SF linker function, only those integrins (alpha(3)beta(1), alpha(6)beta(1), and a chimeric "X3TC5" alpha(3) mutant) that associated strongly with tetraspanins were found in association with PKC. We propose that PKC-TM4SF-integrin structures represent a novel type of signaling complex. The simultaneous binding of TM4SF proteins to the extracellular domains of the integrin alpha(3) subunit and to intracellular PKC helps to explain why the integrin alpha3 extracellular domain is needed for both intracellular PKC recruitment and PKC-dependent phosphorylation of the alpha(3) integrin cytoplasmic tail.
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Affiliation(s)
- X A Zhang
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Harvard Medical School, 44 Binney Street, Boston, MA 02115, USA
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YÁÑEZ-MÓ MARÍA, MITTELBRUNN MARÍA, SÁNCHEZ-MADRID FRANCISCO. Tetraspanins and Intercellular Interactions. Microcirculation 2001. [DOI: 10.1111/j.1549-8719.2001.tb00166.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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