Stephanie Charrin

Publications (3)16.15 Total impact

• Source

  Available from: Laurence Cocquerel

  Article: The Ig domain protein CD9P-1 down-regulates CD81 ability to support Plasmodium yoelii infection.

  Stéphanie Charrin, Samir Yalaoui, Birke Bartosch, Laurence Cocquerel, Jean-François Franetich, Claude Boucheix, Dominique Mazier, Eric Rubinstein, Olivier Silvie
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  ABSTRACT: Invasion of hepatocytes by Plasmodium sporozoites is a prerequisite for establishment of a malaria natural infection. The molecular mechanisms underlying sporozoite invasion are largely unknown. We have previously reported that CD81 is required on hepatocytes for infection by Plasmodium falciparum and Plasmodium yoelii sporozoites. CD81 belongs to the tetraspanin superfamily of transmembrane proteins. By interacting with each other and with other transmembrane proteins, tetraspanins may play a role in the lateral organization of membrane proteins. In this study, we investigated the role of the two major molecular partners of CD81 in hepatocytic cells, CD9P-1/EWI-F and EWI-2, two transmembrane proteins belonging to a novel subfamily of immunoglobulin proteins. We show that CD9P-1 silencing increases the host cell susceptibility to P. yoelii sporozoite infection, whereas EWI-2 knock-down has no effect. Conversely, overexpression of CD9P-1 but not EWI-2 partially inhibits infection. Using CD81 and CD9P-1 chimeric molecules, we demonstrate the role of transmembrane regions in CD81-CD9P-1 interactions. Importantly, a CD9P-1 chimera that no longer associates with CD81 does not affect infection. Based on these data, we conclude that CD9P-1 acts as a negative regulator of P. yoelii infection by interacting with CD81 and regulating its function.
  Journal of Biological Chemistry 09/2009; 284(46):31572-8. · 4.77 Impact Factor
• Source

  Available from: bioscience.org

  Article: Role of ERM (ezrin-radixin-moesin) proteins in T lymphocyte polarization, immune synapse formation and in T cell receptor-mediated signaling.

  Stephanie Charrin, Andres Alcover
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  ABSTRACT: Following antigen recognition, T lymphocytes undergo strong actin cytoskeletal rearrangements. These play a crucial role in the molecular reorganization at the contact site between the T lymphocyte and the antigen presenting cell, termed the immunological synapse. Moreover, they are necessary for T cell activation that leads to cytokine secretion, T cell proliferation and effector function. Little is known on how membrane and signaling molecules interact with the actin cytoskeleton during these processes. Here we review the function of the ERM family of membrane-microfilament linkers, making emphasis on the role of these proteins in T lymphocyte physiology. We discuss how ERM proteins are involved in membrane reorganization during T lymphocyte polarization and immune synapse formation, and how these proteins may contribute to T cell receptor-mediated intracellular signaling that leads to T cell activation.
  Frontiers in Bioscience 02/2006; 11:1987-97. · 3.52 Impact Factor
• Article: EWI2/PGRL associates with the metastasis suppressor KAI1/CD82 and inhibits the migration of prostate cancer cells.

  Xin A Zhang, William S Lane, Stephanie Charrin, Eric Rubinstein, Lei Liu
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  ABSTRACT: Cancer metastasis suppressor KAI1/CD82 belongs to the tetraspanin superfamily and inversely correlates with the metastatic potential of a variety of cancers. The mechanism of KAI1/CD82-mediated metastasis suppression remains unclear. In this study, we found a M(r) 68,00 cell-surface protein physically associated with KAI1/CD82 and named it KASP: a KAI1/CD82-associated surface protein. Distinctive from known KAI1/CD82 associations that usually occur in the context of "tetraspanin web," the KAI1/CD82-KASP association is likely to be direct because it is: (a) highly stoichiometric; (b) stabilized by chemical cross-linking; and (c) independent of cholesterol-enriched lipid rafts. Therefore, KASP is one of the major transmembrane proteins that associates with KAI1/CD82. Consistent with the wide distribution of KAI1/CD82, KASP is expressed ubiquitously in human tissues. Through peptide sequencing, KASP was identified as an immunoglobulin superfamily member called EWI2 or PGRL. Although EWI2/PGRL has been found to associate with tetraspanins CD9 and CD81, it forms distinct complexes with different tetraspanins, and its association with KAI1/CD82 could be independent of CD81 and CD9. Overexpression of EWI2/PGRL in Du145 metastatic prostate cancer cells inhibits cell migration on both fibronectin- and laminin-coated substratum, indicating that EWI2/PGRL directly regulates cell migration. Furthermore, EWI2/PGRL synergizes KAI1/CD82 in inhibiting cell migration, indicating that EWI2/PGRL is likely required for the function of KAI1/CD82. In summary, we identified a major KAI1/CD82-associated protein, EWI2/PGRL, that is important for KAI1/CD82-mediated suppression of cancer cell migration.
  Cancer Research 06/2003; 63(10):2665-74. · 7.86 Impact Factor