title: CD81 regulates cell migration through its association with Rac GTPase.
abstract: CD81 is a member of the tetraspanin family that has been described to have a key role in cell migration of tumor and immune cells. To unravel the mechanisms of CD81-regulated cell migration, we performed proteomic analyses that revealed an interaction of the tetraspanin C-terminal domain with the small GTPase Rac. Direct interaction was confirmed biochemically. Moreover, microscopy cross-correlation analysis demonstrated the in situ integration of both molecules into the same molecular complex. Pull-down experiments revealed that CD81-Rac interaction was direct and independent of Rac activation status. Knockdown of CD81 resulted in enhanced protrusion rate, altered focal adhesion formation, and decreased cell migration, correlating with increased active Rac. Reexpression of wild-type CD81, but not its truncated form lacking the C-terminal cytoplasmic domain, rescued these effects. The phenotype of CD81 knockdown cells was mimicked by treatment with a soluble peptide with the C-terminal sequence of the tetraspanin. Our data show that the interaction of Rac with the C-terminal cytoplasmic domain of CD81 is a novel regulatory mechanism of the GTPase activity turnover. Furthermore, they provide a novel mechanism for tetraspanin-dependent regulation of cell motility and open new avenues for tetraspanin-targeted reagents by the use of cell-permeable peptides.
authors.affiliation: Unidad de Investigación, Hospital Santa Cristina, Instituto de Investigación Sanitaria La Princesa, 2006 Madrid, Spain.
authors.forename: Emilio
authors.initials: E
authors.lastname: Tejera
authors.forename: Vera
authors.initials: V
authors.lastname: Rocha-Perugini
authors.forename: Soraya
authors.initials: S
authors.lastname: López-Martín
authors.forename: Daniel
authors.initials: D
authors.lastname: Pérez-Hernández
authors.forename: Alexia I
authors.initials: AI
authors.lastname: Bachir
authors.forename: Alan Rick
authors.initials: AR
authors.lastname: Horwitz
authors.forename: Jesús
authors.initials: J
authors.lastname: Vázquez
authors.forename: Francisco
authors.initials: F
authors.lastname: Sánchez-Madrid
authors.forename: María
authors.initials: M
authors.lastname: Yáñez-Mo
mesh_terms: D000595:Amino Acid Sequence; D018957:CD59 Antigens / Q000378:metabolism; D002448:Cell Adhesion; D002465:Cell Movement; D004789:Enzyme Activation; D015870:Gene Expression; D057809:HEK293 Cells; D061307:Human Umbilical Vein Endothelial Cells / Q000502:physiology; D006801:Humans; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D021381:Protein Transport; D060185:Tetraspanin 24 / Q000378:metabolism; D060225:Tetraspanin 28 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D059008:Time-Lapse Imaging; D020830:rac1 GTP-Binding Protein / Q000378:metabolism*
chemical_list: C554715:CD151 protein, human; D018957:CD59 Antigens; C554798:CD81 protein, human; C107953:RAC1 protein, human; D060185:Tetraspanin 24; D060225:Tetraspanin 28; C051590:CD59 protein, human; D020830:rac1 GTP-Binding Protein