A Cdc42 mutant specifically activated by intersectin.
A Cdc42 mutant specifically activated by intersectin.
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DOI：
10.1021/bi050591b
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发表时间：
2005-10
期刊：
影响因子：
2.9
通讯作者：
William J Smith;Brant Hamel;M. Yohe;J. Sondek;R. Cerione;J. T. Snyder
中科院分区：
文献类型：
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作者：
William J Smith;Brant Hamel;M. Yohe;J. Sondek;R. Cerione;J. T. Snyder
Rho家族GTPase Cdc42作为分子开关发挥作用，控制许多基本细胞过程，例如细胞骨架调节、细胞极性和囊泡运输。Dbl家族的鸟嘌呤核苷酸交换因子通过催化结合的GDP的去除激活Cdc42和其他Rho GTP酶，允许GTP加载，以及随后的效应物识别最终导致下游信号传导事件。现有的结构数据的分析表明，Dbl交换因子intersectin从事严格保守的GTdR残基Cdc42（酪氨酸32）在一个独特的模式相对于所有其他可视化的交换因子Rho GTdR接口。为了研究这种差异结合结构，我们分析了Cdc42的酪氨酸32在结合中的作用，以及Dbl家族交换因子的刺激。酪氨酸32的羟基侧链的缺失显著增加了Cdc42对intersectin的亲和力，但严重削弱了与Dbs的相互作用，Dbs是Cdc42的通常有效的交换因子。此外，Cdc42（Y32F）是专门激活的交叉蛋白，而几乎不响应其他Cdc42激活交换因子在体外和体内。此外，结构决定因素独特的交叉，允许选择性识别和伴随的刺激Cdc42（Y32F），已被定义。Cdc42和其他单个Rho GTP酶从多种Dbl交换因子接收输入刺激信号，因此，Cdc42（Y32F）可以作为用于理解ITSN对Cdc42介导的信号传导现象的特定影响的有价值的试剂。
The Rho family GTPase Cdc42 functions as a molecular switch and controls many fundamental cellular processes such as cytoskeletal regulation, cell polarity, and vesicular trafficking. Guanine nucleotide exchange factors of the Dbl family activate Cdc42 and other Rho GTPases by catalyzing the removal of bound GDP, allowing for GTP loading, and subsequent effector recognition ultimately leading to downstream signaling events. Analysis of existing structural data reveals that the Dbl exchange factor intersectin engages a strictly conserved GTPase residue of Cdc42 (tyrosine 32) in a unique mode with respect to all other visualized exchange factor-Rho GTPase interfaces. To investigate this differential binding architecture, we analyzed the role of tyrosine 32 of Cdc42 in binding, and stimulation by Dbl family exchange factors. Deletion of the hydroxyl side chain of tyrosine 32 substantially increases the affinity of Cdc42 for intersectin, yet severely cripples interaction with Dbs, a normally potent exchange factor of Cdc42. Moreover, Cdc42(Y32F) is exclusively activated by intersectin, while virtually unresponsive to other Cdc42-activating exchange factors in vitro and in vivo. Further, the structural determinants unique to intersectin, which permit selective recognition and concomitant stimulation of Cdc42(Y32F), have been defined. Cdc42 and other individual Rho GTPases receive input stimulatory signals from a multitude of Dbl exchange factors, and therefore, Cdc42(Y32F) could act as a valuable reagent for understanding the specific influence of ITSN on Cdc42-mediated signaling phenomena.