Regulated membrane localization of Tiam1, mediated by the NH2-terminal pleckstrin homology domain, is required for Rac-dependent membrane ruffling and C-Jun NH2-terminal kinase activation.
Regulated membrane localization of Tiam1, mediated by the NH2-terminal pleckstrin homology domain, is required for Rac-dependent membrane ruffling and C-Jun NH2-terminal kinase activation.
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DOI：
10.1083/jcb.137.2.387
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发表时间：
1997-04-21
影响因子：
7.8
通讯作者：
Collard, JG
中科院分区：
文献类型：
--
作者：
Michiels, F;Stam, JC;Hordijk, PL;vanderKammen, RA;RuulsVanStalle, L;Feltkamp, CA;Collard, JG
Rho样gtpase，包括Cdc42， Rac和Rho，调节控制肌动蛋白细胞骨架结构和转录激活的信号通路。Tiam1基因编码Rac1的激活因子，与组成型激活（V12）Rac1类似，Tiam1在成纤维细胞中的过表达诱导膜褶的形成。Tiam1含有一个Dbl同源（DH）结构域和邻近的pleckstrin同源（PH）结构域，这是rho样gtpase激活剂的标志。Tiam1的独特之处在于它在nh2末端有一个额外的PH结构域和一个圆盘大小的同源区域。本研究表明，在成纤维细胞和COS细胞中，Tiam1的膜定位是诱导膜褶皱的必要条件。详细的突变分析，结合共聚焦激光扫描显微镜和免疫电镜，表明Tiam1的nh2末端PH结构域，而不是dh邻近的PH结构域，是膜结合所必需的。Tiam1的nh2末端PH结构域可以被c-Src的肉豆蔻酰基化膜定位结构域在功能上取代，这表明该PH结构域的主要功能是在膜上定位蛋白质。血清饥饿后，血清可诱导Tiam1的膜结合和褶皱，提示受体刺激可诱导Tiam1的膜易位。与V12Rac1类似，Tiam1刺激c-Jun nh2末端激酶（JNK）的活性。这种依赖rac的JNK刺激也需要Tiam1的膜结合。我们得出结论，Tiam1通过其nh2末端PH结构域的膜定位调控决定了不同rac介导的信号通路的激活。
Rho-like GTPases, including Cdc42, Rac, and Rho, regulate signaling pathways that control actin cytoskeletal structures and transcriptional activation. The Tiam1 gene encodes an activator of Rac1, and similarly to constitutively activated (V12)Rac1, overexpression of Tiam1 in fibroblasts induces the formation of membrane ruffles. Tiam1 contains a Dbl homology (DH) domain and adjacent pleckstrin homology (PH) domain, hallmarks for activators of Rho-like GTPases. Unique for Tiam1 are an additional PH domain and a Discs-large homology region in the NH2-terminal part of the protein. Here we show that both in fibroblasts and COS cells, membrane localization of Tiam1 is required for the induction of membrane ruffling. A detailed mutational analysis, in combination with confocal laser scanning microscopy and immunoelectron microscopy, demonstrates that the NH2-terminal PH domain of Tiam1, but not the DH-adjacent PH domain, is essential for membrane association. This NH2-terminal PH domain of Tiam1 can be functionally replaced by the myristoylated membrane localization domain of c-Src, indicating that the primary function of this PH domain is to localize the protein at the membrane. After serum starvation, both membrane association of Tiam1 and ruffling can be induced by serum, suggesting that receptor stimulation induces membrane translocation of Tiam1. Similar to V12Rac1, Tiam1 stimulates the activity of the c-Jun NH2-terminal kinase (JNK). This Rac-dependent stimulation of JNK also requires membrane association of Tiam1. We conclude that the regulated membrane localization of Tiam1 through its NH2-terminal PH domain determines the activation of distinct Rac-mediated signaling pathways.
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影响因子：
64.5
作者：
Kolanus, W;Nagel, W;Seed, B
通讯作者：
Seed, B
影响因子：
64.5
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MINDEN, A;LIN, AN;KARIN, M
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KARIN, M
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64.5
作者：
HABETS, GGM;SCHOLTES, EHM;COLLARD, JG
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COLLARD, JG
影响因子：
3.9
作者：
NOBES, CD;HALL, A
通讯作者：
HALL, A
影响因子：
64.5
作者：
NOBES, CD;HALL, A
通讯作者：
HALL, A