title: Roles of IQGAP1 in cell polarization and migration.
abstract: Cell polarization and migration are fundamental processes in all organisms and are stringently regulated during tissue development, chemotaxis and wound healing. Migrating cells have a polarized morphology with an asymmetric distribution of signalling molecules and the cytoskeleton. Linkage of microtubule plus ends to the cortical region is essential for polarized migration. +TIPs, including CLIP-170 and APC (adenomatous polyposis coli) are thought to function as capturing devices at specialized cortical regions. Rho family GTPases, particularly Rac1 and Cdc42, play pivotal roles in cell polarization and migration acting through their effectors. We found that IQGAP1, an effector of Rac1 and Cdc42, interacts with CLIP-170. Activated Rac1 and Cdc42 enhance the binding of IQGAP1 to CLIP-170, and capture GFP-CLIP-170 at the base of leading edges and filopodia, respectively. Recently, we found that IQGAP1 directly binds to APC in addition to CLIP-170. IQGAP1 and APC interdependently localize to leading edges in migrating cells. IQGAP1 can link APC to actin filaments in vitro. Thus, activation of Rac1 and Cdc42 in response to migration signals leads to recruitment of IQGAP1 and APC which, together with CLIP-170, form a complex that links the actin cytoskeleton and microtubule dynamics during cell polarization and migration.
authors.affiliation: Department of Cell Pharmacology, Nagoya University, Graduate School of Medicine, Showa, Aichi, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Watanabe
authors.forename: Jun
authors.initials: J
authors.lastname: Noritake
authors.forename: Kozo
authors.initials: K
authors.lastname: Kaibuchi
mesh_terms: D000199:Actins / Q000378:metabolism; D011125:Adenomatous Polyposis Coli; D000818:Animals; D002465:Cell Movement / Q000502:physiology*; D016764:Cell Polarity / Q000502:physiology*; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism; D009363:Neoplasm Proteins / Q000378:metabolism; D020764:cdc42 GTP-Binding Protein / Q000378:metabolism; D020830:rac1 GTP-Binding Protein / Q000378:metabolism; D020703:ras GTPase-Activating Proteins / Q000378:metabolism*; D020741:rho GTP-Binding Proteins / Q000378:metabolism
chemical_list: D000199:Actins; C101203:IQ motif containing GTPase activating protein 1; D008869:Microtubule-Associated Proteins; D009363:Neoplasm Proteins; D020703:ras GTPase-Activating Proteins; C076744:cytoplasmic linker protein 170; D020764:cdc42 GTP-Binding Protein; D020830:rac1 GTP-Binding Protein; D020741:rho GTP-Binding Proteins