CdGAP, a novel proline-rich GTPase-activating protein for Cdc42 and Rac
CdGAP, a novel proline-rich GTPase-activating protein for Cdc42 and Rac
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DOI：
10.1074/jbc.273.44.29172
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发表时间：
1998-10-30
影响因子：
4.8
通讯作者：
Hall, A
中科院分区：
文献类型：
--
作者：
Lamarche-Vane, N;Hall, A
Cdc42 介导多种信号通路，导致肌动蛋白重组、转录激活和细胞周期控制。 Cdc42 的突变分析表明，肌动蛋白重组和转录激活是通过独立的信号通路诱导的。 Cdc42 的 Y40C 效应突变体不再与其许多已知的靶蛋白相互作用，例如 p65(PAK) 和 WASP，但该突变体仍然可以诱导丝状伪足形成。为了鉴定参与肌动蛋白重排的Cdc42靶标，我们使用Cdc42的Y40C突变体作为诱饵筛选了酵母双杂交cDNA文库。我们在这里报告了一种新型富含丝氨酸和脯氨酸的 GTP 酶激活蛋白 CdGAP 的鉴定，它在体外对 Cdc42 和 Pac 都有活性，将 CdGAP 显微注射到血清饥饿的成纤维细胞中，分别抑制由 Pac 和 Cdc42 介导的血小板衍生生长因子诱导的板状伪足和缓激肽诱导的丝状伪足。 CdGAP 对 Rho 没有体外活性，并且当显微注射到成纤维细胞中时，它对溶血磷脂酸诱导的应力纤维形成没有影响。 CdGAP 的羧基末端揭示了潜在的蛋白激酶 C 磷酸化位点和五个 SH3 结合基序。因此，CdGAP 是一种新型 GAP，可能参与 Cdc42 和 Pac 诱导的信号通路，从而导致肌动蛋白重组。
Cdc42 mediates several signaling pathways leading to actin reorganization, transcriptional activation, and cell cycle control. Mutational analysis of Cdc42 has revealed that actin reorganization and transcriptional activation are induced through independent signaling pathways. The Y40C effector mutant of Cdc42 no longer interacts with many of its known target proteins, such as p65(PAK) and WASP, yet this mutant can still induce filopodia formation. To identify Cdc42 targets involved in actin rearrangements, we have screened a yeast two-hybrid cDNA library using the Y40C mutant of Cdc42 as a bait. We report here the identification of a novel serine- and proline-rich GTPase-activating protein, CdGAP, which is active in vitro on both Cdc42 and Pac, Microinjection of CdGAP into serum starved fibroblasts inhibits both platelet-derived growth factor-induced lamellipodia and bradykinin-induced filopodia mediated by Pac and Cdc42, respectively. CdGAP does not show in vitro activity toward Rho, and it has no effect on lysophosphatidic acid-induced stress fiber formation when microinjected into fibroblasts. The carboxyl terminus of CdGAP reveals potential protein kinase C phosphorylation sites and five SH3 binding motifs. Thus, CdGAP is a novel GAP that is likely to participate in Cdc42- and Pac-induced signaling pathways leading to actin reorganization.