Roles of an N-terminal coiled-coil-containing domain in the localization and function of Bem3, a Rho GTPase-activating protein in budding yeast
Roles of an N-terminal coiled-coil-containing domain in the localization and function of Bem3, a Rho GTPase-activating protein in budding yeast
复制标题
N 末端卷曲螺旋结构域在 Bem3（芽殖酵母中 Rho GTP 酶激活蛋白）的定位和功能中的作用
DOI：
10.1016/j.fgb.2016.12.010
复制
发表时间：
2017-02-01
影响因子：
3
通讯作者：
Gao, Xiang-Dong
中科院分区：
文献类型：
--
作者：
Nie, Wen-Chao;He, Fei;Gao, Xiang-Dong
GTPase-activating proteins (GAPs) play critical roles in the spatial and temporal control of small GTPases. The budding yeast Bem3 is a GAP for Cdc42, a Rho GTPase crucial for actin and septin organization. Bem3 localizes to the sites of polarized growth. However, the amino acid sequence determinants mediating recruitment of Bem3 to its physiological sites of action and those important for Bem3 function are not clear. Here, we show that Bem3's localization is guided by two distinct targeting regions the PX-PH-domain-containing TD1 and the coiled-coil-containing TD2. TD2 localization is largely mediated by its interaction with the polarisome component Epo1 via heterotypic coiled-coil interaction. This finding reveals a novel role for the polarisome in linking Bem3 to its functional target, Cdc42. We also show that the coiled-coil domain of Bem3 interacts homotypically and this interaction is important for the regulation of Cdc42 by Bem3. Moreover, we show that overexpression of a longer version of the TD2 domain disrupts septin-ring assembly in a RhoGAP-independent manner, suggesting that TD2 may be capable of interacting with proteins implicated in septin-ring assembly. Furthermore, we show that the longer version of TD2 interacts with Kss1, a MAPK involved in filamentous growth. Kss1 is reported to localize mainly in the nucleus. We find that Kss1 also localizes to the sites of polarized growth and Bem3 interacts with Kss1 at the septin-ring assembly site. Our study provides new insights in Bem3's localization and function. (C) 2017 Elsevier Inc. All rights reserved.
