Roles of the PH, coiled-coil and SAM domains of the yeast polarity protein Boi2 in polarity-site localization and function in polarized growth
Roles of the PH, coiled-coil and SAM domains of the yeast polarity protein Boi2 in polarity-site localization and function in polarized growth
复制标题
酵母极性蛋白 Boi2 的 PH、卷曲螺旋和 SAM 结构域在极性位点定位中的作用以及极化生长中的功能。
DOI：
10.1007/s00294-020-01093-9
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发表时间：
2020-07-12
期刊：
影响因子：
2.5
通讯作者：
Gao, Xiang-Dong
中科院分区：
文献类型：
--
作者：
Jia, Zhi-Wen;Lv, Si-Xu;Gao, Xiang-Dong
Boi1 和 Boi2 是芽殖酵母芽形成所必需的旁系同源蛋白。到目前为止，将 Boi1/Boi2 定位到极性位点的结构域以及在芽形成中的功能尚不清楚。在这里，我们报道了 Boi2 的卷曲螺旋结构域与相邻的 PH 结构域配合，赋予 Boi2 的芽皮层定位和细胞生长的主要功能。 PH-CC 双结构域的 PH 结构域部分与 Rho GTPases Cdc42 和 Rho3 相互作用，并且两种相互作用均独立于每个 GTPase 的 GTP/GDP 结合状态。有趣的是，高拷贝RHO3和BOI2而非CDC42抑制了RGA1-C538过表达和sec15-1突变体的生长缺陷，并且BOI2的功能依赖于RHO3，表明Boi2可能在Rho3途径中发挥作用。 Boi2 的 SAM 结构域在两个突变体的高拷贝抑制以及 Boi2 的早期芽颈定位中发挥着重要作用。 SAM 结构域和 CC 结构域也具有同型相互作用。它们可能参与含有 Boi2 的蛋白质复合物的形成。我们的结果为 Boi2 的定位和功能提供了新的见解，并强调了 PH-CC 双结构域和 SAM 结构域在 Boi2 定位和功能中的重要性。
Boi1 and Boi2 are paralogous proteins essential for bud formation in budding yeast. So far, the domains that target Boi1/Boi2 to the polarity sites and function in bud formation are not well understood. Here, we report that a coiled-coil domain of Boi2 cooperates with the adjacent PH domain to confer Boi2's bud-cortex localization and major function in cell growth. The PH domain portion of the PH-CC bi-domain interacts with the Rho GTPases Cdc42 and Rho3 and both interactions are independent of the GTP/GDP-bound state of each GTPase. Interestingly, high-copyRHO3andBOI2but notCDC42suppressed the growth defect ofRGA1-C538overexpression and thesec15-1mutant and thisBOI2function depends onRHO3, suggesting that Boi2 may function in the Rho3 pathway. The SAM domain of Boi2 plays an essential role in high-copy suppression of the two mutants as well as in the early bud-neck localization of Boi2. The SAM domain and the CC domain also interact homotypically. They are likely involved in the formation of Boi2-containing protein complex. Our results provide new insights in the localization and function of Boi2 and highlight the importance of the PH-CC bi-domain and the SAM domain in Boi2's localization and function.