Noncanonical Myo9b-RhoGAP Accelerates RhoA GTP Hydrolysis by a Dual-Arginine-Finger Mechanism

JOURNAL OF MOLECULAR BIOLOGY

卷:428

Article

Yi, Fengshuang^1,5  Kong, Ruirui²  Ren, Jinqi¹  Zhu, Li²  Lou, Jizhong³  Wu, Jane Y.^2,4  Feng, Wei¹ 

[1] Chinese Acad Sci, Inst Biophys, CAS Ctr Excellence Biomacromol, Natl Lab Biomacromol, 15 Datun Rd, Beijing 100101, Peoples R China

[2] Chinese Acad Sci, Inst Biophys, State Key Lab Brain & Cognit Sci, 15 Datun Rd, Beijing 100101, Peoples R China

[3] Chinese Acad Sci, Inst Biophys, Key Lab RNA Biol, 15 Datun Rd, Beijing 100101, Peoples R China

[4] Northwestern Univ, Feinberg Sch Med, Lurie Canc Ctr, Dept Neurol,Ctr Genet Med, 303 E Super, Chicago, IL 60611 USA

[5] Univ Chinese Acad Sci, Beijing 100049, Peoples R China

关键词: Rho GTPases;    GTPase-activating proteins;    RhoGAP domain;    Myo9b;    RhoA;   

DOI  :  10.1016/j.jmb.2016.06.014

来源: Elsevier

【 摘 要 】

The GTP hydrolysis activities of Rho GTPases are stimulated by GTPase-activating proteins (GAPs), which contain a RhoGAP domain equipped with a characteristic arginine finger and an auxiliary asparagine for catalysis. However, the auxiliary asparagine is missing in the RhoGAP domain of Myo9b (Myo9b-RhoGAP), a unique motorized RhoGAP that specifically targets RhoA for controlling cell motility. Here, we determined the structure of Myo9b-RhoGAP in complex with GDP-bound RhoA and magnesium fluoride. Unexpectedly, Myo9b-RhoGAP contains two arginine fingers at its catalytic site. The first arginine finger resembles the one within the canonical RhoGAP domains and inserts into the nucleotide-binding pocket of RhoA, whereas the second arginine finger anchors the Switch I loop of RhoA and interacts with the nucleotide, stabilizing the transition state of GTP hydrolysis and compensating for the lack of the asparagine. Mutating either of the two arginine fingers impaired the catalytic activity of Myo9b-RhoGAP and affected the Myo9b-mediated cell migration. Our data indicate that Myo9b-RhoGAP accelerates RhoA GTP hydrolysis by a previously unknown dual-arginine-finger mechanism, which may be shared by other noncanonical RhoGAP domains lacking the auxiliary asparagine. (C) 2016 Elsevier Ltd. All rights reserved.

【 授权许可】

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