title: SPIN90-IRSp53 complex participates in Rac-induced membrane ruffling.
abstract: SPIN90 is a key regulator of actin cytoskeletal organization. Using the BioGRID(beta) database (General Repository for Interaction Datasets), we identified IRSp53 as a binding partner of SPIN90, and confirmed the in vivo formation of a SPIN90-IRSp53 complex mediated through direct association of the proline-rich domain (PRD) of SPIN90 with the SH3 domain of IRSp53. SPIN90 and IRSp53 positively cooperated to mediate Rac activation, and co-expression of SPIN90 and IRSp53 in COS-7 cells led to the complex formation of SPIN90-IRSp53 in the leading edge of cells. PDGF treatment induced strong colocalization of SPIN90 and IRSp53 at membrane protrusions. Within such PDGF-induced protrusions, knockdown of SPIN90 protein using siRNA significantly reduced lamellipodia-like protrusions as well as localization of IRSp53 at those sites. Finally, competitive inhibition of SPIN90-IRSp53 binding by SPIN90 PRD dramatically reduced ruffle formation, further suggesting that SPIN90 plays a key role in the formation of the membrane protrusions associated with cell motility.
authors.affiliation: Bio Imaging Research Center, Cell Dynamics Research Center, Department of Life Science, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712, South Korea.
authors.forename: Carmen
authors.initials: C
authors.lastname: Teodorof
authors.forename: Jeom Il
authors.initials: JI
authors.lastname: Bae
authors.forename: Seon-Myung
authors.initials: SM
authors.lastname: Kim
authors.forename: Hye Jin
authors.initials: HJ
authors.lastname: Oh
authors.forename: Yong Seok
authors.initials: YS
authors.lastname: Kang
authors.forename: Jeonghoon
authors.initials: J
authors.lastname: Choi
authors.forename: Jang-Soo
authors.initials: JS
authors.lastname: Chun
authors.forename: Woo Keun
authors.initials: WK
authors.lastname: Song
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D019556:COS Cells; D002462:Cell Membrane / Q000378:metabolism* / Q000648:ultrastructure; D002465:Cell Movement / Q000502:physiology; D022081:Cell Surface Extensions; D002522:Chlorocebus aethiops; D055785:Gene Knockdown Techniques; D005822:Genetic Vectors / Q000378:metabolism; D006801:Humans; D009124:Muscle Proteins / Q000235:genetics / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D034741:RNA, Small Interfering / Q000378:metabolism; D014162:Transfection; D020744:rac GTP-Binding Proteins / Q000378:metabolism*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C119539:BAIAP2 protein, human; D009124:Muscle Proteins; C486062:NCKIPSD protein, human; D009419:Nerve Tissue Proteins; D010982:Platelet-Derived Growth Factor; D034741:RNA, Small Interfering; D020744:rac GTP-Binding Proteins