Kiyokawa Etsuko, Matsuda Michiyuki
Department of Pathology and Biology of Diseases, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto, Japan.
Cell Adh Migr. 2009 Jul-Sep;3(3):281-4. doi: 10.4161/cam.3.3.8857. Epub 2009 Jul 27.
DOCK180 is an atypical guanine nucleotide exchange factor of Rac1 identified originally as one of the two major proteins bound to the SH3 domain of the Crk adaptor protein. DOCK180 induces tyrosine phosphorylation of p130(Cas), and recruits the Crk-p130(Cas) complex to focal adhesions. Recently, we searched for DOCK180-binding proteins with a nano-LC/MS/MS system, and found that ANKRD28, a protein with twenty-six ankyrin domain-repeats, interacts with the SH3 domain of DOCK180. Knockdown of ANKRD28 reduced the migration velocity and altered the distribution of focal adhesion proteins such as Crk, paxillin and p130(Cas). On the other hand, the expression of ANKRD28, p130(Cas), Crk and DOCK180 induced hyper-phosphorylation of p130(Cas), which paralleled the induction of multiple long cellular processes. Depletion of ELMO, another protein bound to the SH3 domain of DOCK180, also retarded cell migration, but its expression together with p130(Cas), Crk and DOCK180 induced extensive lamellipodial protrusion around the entire circumference without 130(Cas) hyperphosphorylation. These data suggest the dual modes of DOCK180-Rac regulation for cell migration.
DOCK180是Rac1的一种非典型鸟嘌呤核苷酸交换因子，最初被鉴定为与Crk衔接蛋白的SH3结构域结合的两种主要蛋白质之一。DOCK180诱导p130(Cas)的酪氨酸磷酸化，并将Crk-p130(Cas)复合物募集到粘着斑。最近，我们用纳升级液相色谱-串联质谱系统寻找与DOCK180结合的蛋白质，发现ANKRD28，一种具有26个锚蛋白结构域重复序列的蛋白质，与DOCK180的SH3结构域相互作用。敲低ANKRD28会降低迁移速度，并改变粘着斑蛋白如Crk、桩蛋白和p130(Cas)的分布。另一方面，ANKRD28、p130(Cas)、Crk和DOCK180的表达诱导p130(Cas)的过度磷酸化，这与多个长细胞突起的诱导平行。耗尽ELMO，另一种与DOCK180的SH3结构域结合的蛋白质，也会阻碍细胞迁移，但其与p130(Cas)、Crk和DOCK180一起表达会在整个圆周周围诱导广泛的片状伪足突出，而不会导致130(Cas)过度磷酸化。这些数据表明DOCK180-Rac对细胞迁移的调控有两种模式。
