GEFH1 结合 ASAP1 并调节足突形成。
GEFH1 binds ASAP1 and regulates podosome formation.
机构信息
Laboratory of Cellular and Molecular Biology, National Cancer Institute, National Institutes of Health, Bldg 37 Room 2042, Bethesda, MD 20892, United States.
出版信息
Biochem Biophys Res Commun. 2011 Mar 25;406(4):574-9. doi: 10.1016/j.bbrc.2011.02.093. Epub 2011 Feb 23.
Invadopodia are cellular structures that are thought to mediate tumor invasion. ASAP1, an Arf GTPase-activating protein (GAP) containing a BAR domain, is a substrate of Src. ASAP1 is required for the assembly of invadopodia and podosomes, which are Src-induced structures related to invadopodia in NIH 3T3 fibroblasts. The BAR domain of ASAP1 is required for the assembly of podosomes. Using two-hybrid screening, we have identified GEFH1, a guanine nucleotide exchange factor for RhoA, as a binding partner of the BAR domain of ASAP1. We validated the interaction of endogenous GEFH1 with ASAP1 by immunoprecipitation, and found GEFH1 colocalized with ASAP1 in podosomes. The overexpression of GEFH1 inhibited podosome assembly and ASAP1 catalytic activity as a GAP. A mutant of GEFH1 lacking the domain that binds to the BAR domain of ASAP1 was less effective. Reduced expression of GEFH1, achieved with siRNA treatment, did not affect matrix degradation by podosomes but increased the rate of podosome assembly. Based on these results, we conclude that GEFH1 is a negative regulator of podosomes.
侵袭伪足是一种被认为介导肿瘤侵袭的细胞结构。ASAP1 是一种含有 BAR 结构域的 Arf GTPase 激活蛋白（GAP），是 Src 的底物。ASAP1 是侵袭伪足和 podosomes 组装所必需的，podosomes 是 NIH 3T3 成纤维细胞中与侵袭伪足相关的 Src 诱导结构。ASAP1 的 BAR 结构域是 podosomes 组装所必需的。通过双杂交筛选，我们已经鉴定出 GEFH1，一种 RhoA 的鸟嘌呤核苷酸交换因子，是 ASAP1 的 BAR 结构域的结合伴侣。我们通过免疫沉淀验证了内源性 GEFH1 与 ASAP1 的相互作用，并发现 GEFH1 与 ASAP1 在 podosomes 中共定位。GEFH1 的过表达抑制了 podosomes 的组装和 ASAP1 作为 GAP 的催化活性。缺乏与 ASAP1 的 BAR 结构域结合的结构域的 GEFH1 突变体效果较差。用 siRNA 处理降低 GEFH1 的表达不会影响 podosomes 对基质的降解，但会增加 podosomes 组装的速度。基于这些结果，我们得出结论，GEFH1 是 podosomes 的负调节剂。
Zotero 插件