p130Cas regulates the activity of AND-34, a novel Ra1, Rap1, and R-Ras guanine nucleotide exchange factor
p130Cas regulates the activity of AND-34, a novel Ra1, Rap1, and R-Ras guanine nucleotide exchange factor
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DOI：
10.1074/jbc.m003074200
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发表时间：
2000-09-29
影响因子：
4.8
通讯作者：
Lerner, A
中科院分区：
文献类型：
--
作者：
Gotoh, T;Cai, DP;Lerner, A
我们以前发现了一个新的小鼠蛋白And-34，它的羧基末端结构域与RAS家族的鸟嘌呤核苷酸交换因子(GEF)同源，它与焦点黏附对接蛋白p130(Cas)结合。其他人的工作表明，And-34的人类同源物BCAR3和人类p130(Cas)BCAR1都与乳腺癌细胞对抗雌激素他莫昔芬的耐药性有关。在这里，我们报告了And-34在细胞中显示Ra1A、Rap1A和R-RAS上的全球环境基金活性，但不显示Ha-RAS GTP酶。与其他几个RA1-GEF不同的是，RA1-34的全环活性不会被组成活性的Ha-RAS(Val-12)增强，这与缺乏可检测到的RAS结合结构域是一致的。与和-34的有效结合需要p130(Cas)的Src结合域和侧翼羧基末端区域。P130(Cas)结合位点被映射到和-34Gf结构域内的羧基末端序列。P130(Cas)的过表达，但不是p130(Cas)的And-34结合突变体，抑制了共转染And-34的Ra1蛋白的活性。这项工作确定了p130(Cas)的一个新的潜在功能和一个新的调控通路，该通路参与控制Ra1、Rap和R-Ras GTP酶，可能参与乳腺癌细胞对他莫昔芬耐药的进展。
We previously identified a novel murine protein, AND-34, with a carboxyl-terminal domain homologous to Ras family guanine nucleotide exchange factors (GEFs), which bound to the focal adhesion docking protein p130(Cas). Work by others has implicated both the human homologue of AND-34, BCAR3, and human p130(Cas) BCAR1, in the resistance of breast cancer cells to the anti-estrogen tamoxifen. Here we report that AND-34 displays GEF activity on Ra1A, Rap1A, and R-Ras but not Ha-Ras GTPases in cells. In contrast to several other Ra1-GEFs, the Ra1 GEF activity of AND-34 is not augmented by constitutively active Ha-Ras(Val-12), consistent with the absence of a detectable Ras-binding domain. Efficient binding to AND-34 required both the Src-binding domain and a flanking carboxyl-terminal region of p130(Cas). The p130(Cas)-binding site mapped to a carboxyl-terminal sequence within the AND-34 GEF domain. Overexpression of p130(Cas), but not an AND-34-binding mutant of p130(Cas), inhibited the Ra1 GEF activity of co-transfected AND-34. This work identifies a new potential function for p130(Cas) and a new regulatory pathway involved in the control of Ra1, Rap, and R-Ras GTPases that may participate in the progression of breast cancer cells to tamoxifen resistance.