Author/Authors :
Masaki Fukata، نويسنده , , Takashi Watanabe، نويسنده , , Jun Noritake، نويسنده , , Masato Nakagawa، نويسنده , , Masaki Yamaga، نويسنده , , Shinya Kuroda، نويسنده , , Yoshiharu Matsuura، نويسنده , , Akihiro Iwamatsu، نويسنده , , Franck Perez، نويسنده , , Kozo Kaibuchi and Toshio Hakoshima، نويسنده ,
Abstract :
Linkage of microtubules to special cortical regions is essential for cell polarization. CLIP-170 binds to the growing ends of microtubules and plays pivotal roles in orientation. We have found that IQGAP1, an effector of Rac1 and Cdc42, interacts with CLIP-170. In Vero fibroblasts, IQGAP1 localizes at the polarized leading edge. Expression of carboxy-terminal fragment of IQGAP1, which includes the CLIP-170 binding region, delocalizes GFP-CLIP-170 from the tips of microtubules and alters the microtubule array. Activated Rac1/Cdc42, IQGAP1, and CLIP-170 form a tripartite complex. Furthermore, expression of an IQGAP1 mutant defective in Rac1/Cdc42 binding induces multiple leading edges. These results indicate that Rac1/Cdc42 marks special cortical spots where the IQGAP1 and CLIP-170 complex is targeted, leading to a polarized microtubule array and cell polarization.
