Spatio-temporal analysis of DOCK180 during dorsal ruffle formation

受体酪氨酸激酶的激活导致两种不同类型的质膜结构的形成：外周褶皱和背褶皱。虽然这两种褶皱的形成都需要激活小GTP酶Rac，但动力学上的差异表明，它们的褶皱形成有不同的调节机制。DOCK1(DOCK180)和DOCK5是非典型的RAC激活剂，均在小鼠胚胎成纤维细胞(MEF)中表达。我们发现DOCK1缺乏单独损害了MEF的背部褶皱的形成。DOCK1通过C端多元氨基酸簇与磷脂酸(PA)结合，并定位于背褶皱。此外，我们发现，磷脂酶D，一种催化PA合成的酶，是PDGF诱导的背部而不是外围褶皱形成所必需的。这些结果表明，磷脂酶D-PA轴通过调节DOCK1的定位选择性地控制背部褶皱的形成。

Activation of receptor tyrosine kinases leads to the formation of two different types of plasma membrane structures: peripheral ruffles and dorsal ruffles. Although the formation of both ruffle types requires activation of the small GTPase Rac, the difference in kinetics suggests that a distinct regulatory mechanism operates for their ruffle formation. DOCK1(DOCK180) and DOCK5 are atypical Rac activators and are both expressed in mouse embryonic fibroblasts (MEFs). We found that DOCK1 deficiency alone impaired dorsal ruffle formation in MEFs. DOCK1 bound to phosphatidic acid (PA) through the C-terminal polybasic amino acid cluster and was localized to dorsal ruffles. In addition, we show that phospholipase D, an enzyme that catalyzes PA synthesis, is required for PDGF-induced dorsal, but not peripheral, ruffle formation. These results indicate that the phospholipase D-PA axis selectively controls dorsal ruffle formation by regulating DOCK1 localization.