Pragmin, a novel effector of Rnd2 GTPase, stimulates RhoA activity
Pragmin, a novel effector of Rnd2 GTPase, stimulates RhoA activity
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DOI：
10.1074/jbc.m511314200
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发表时间：
2006-04-14
影响因子：
4.8
通讯作者：
Negishi, M
中科院分区：
文献类型：
--
作者：
Tanaka, H;Katoh, H;Negishi, M
小 GTP 酶的 Rho 家族参与肌动蛋白细胞骨架的重组以及随后各种细胞的形态变化。 Rnd2 是 Rnd 亚家族的成员，由 Rnd1、Rnd2 和 Rnd3 组成。与 Rnd1 和 Rnd3 相比，Rnd2 对 RhoA 信号传导具有拮抗作用，但 Rnd2 的信号传导途径尚不清楚。在这里，我们使用 Rnd2 作为诱饵进行了酵母双杂交筛选，并鉴定了一种新型 Rnd2 效应蛋白，主要在神经元中表达，包括皮质和海马神经元。我们将其命名为 Pragmin（Rnd2 的 pragma）。在体内和体外结合测定中，Pragmin 以 GTP 依赖性方式与 Rho 家族 GTPase 中的 Rnd2 特异性结合。 Rnd2 结合的 Pragmin 显着刺激 RhoA 活性，并通过 HeLa 细胞中的 RhoA 和 Rho 激酶途径诱导细胞收缩。在 PC12 细胞中，表达 Pragmin 会抑制神经生长因子诱导的神经突生长，以响应 Rnd2，并且 Pragmin 特异性小干扰 RNA 敲低 Pragmin 会增强神经突伸长。因此，Rnd2 通过 Pragmin 作为 RhoA 激活剂来调节神经突生长，这与 Rnd1 和 Rnd3 抑制 RhoA 信号传导相反。
The Rho family of small GTPases has been implicated in the reorganization of actin cytoskeleton and subsequent morphological changes in various cells. Rnd2 is a member of the Rnd subfamily, comprising Rnd1, Rnd2, and Rnd3. In contrast to Rnd1 and Rnd3, displaying an antagonistic action for RhoA signaling, signaling pathways of Rnd2 are not well known. Here we have performed a yeast two-hybrid screen using Rnd2 as bait and identified a novel Rnd2 effector protein, predominantly expressed in neurons, including cortical and hippocampal neurons. We named it Pragmin (pragma of Rnd2). In in vivo and in vitro binding assays, Pragmin specifically binds to Rnd2 among the Rho family GTPases in a GTP-dependent manner. Rnd2-bound Pragmin significantly stimulates RhoA activity and induces cell contraction through RhoA and the Rho-kinase pathway in HeLa cells. In PC12 cells, expressing Pragmin inhibits nerve growth factor-induced neurite outgrowth in response to Rnd2, and knock-down of Pragmin by Pragmin-specific small interfering RNA enhances neurite elongation. Therefore, Rnd2 regulates neurite outgrowth by functioning as the RhoA activator through Pragmin, in contrast to Rnd1 and Rnd3 inhibiting RhoA signaling.