The polarity-establishment component Bem1p interacts with the exocyst complex through the Sec15p subunit
The polarity-establishment component Bem1p interacts with the exocyst complex through the Sec15p subunit
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DOI：
10.1242/jcs.02849
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发表时间：
2006-03-01
影响因子：
4
通讯作者：
Novick, PJ
中科院分区：
文献类型：
--
作者：
France, YE;Boyd, C;Novick, PJ
绿色荧光蛋白（GFP）标记的Sec15的定位受到影响，特别是在芽生长的早期。此外，Sec15-1p是酿酒酵母（Saccharomyces cerevisiae）分泌机制的空间调控，对新芽的形成至关重要。然而，分泌和细胞极性建立机制之间的串扰机制尚未完全阐明。在这里，我们报道了Sec15p，一个胞囊复合体的亚基，可能提供了一条通信线路。Sec15p不仅是rabb蛋白Sec4p的效应器，Sec4p是后高尔基转运的主要调节因子，而且它还与极性建立机制的组成部分相互作用。我们已经证明了Sec15p和Bem1p之间的直接物理相互作用，Bem1p是一种参与cdc42p介导的极性建立途径的蛋白质，证实了之前的双杂交研究。当这种相互作用受损时，如缺乏Bem1p n端138个残基的细胞，包括第一个src同源3 （SH3）结构域，绿色荧光蛋白（GFP）标记的Sec15的定位受到影响，特别是在芽生长的早期阶段。此外，在Bem1p结合中存在缺陷的Sec15-1p与另一个囊胞亚基Sec8p一起错位。总的来说，我们的证据表明，Sec15p与Bem1p的相互作用对于芽生长早期Sec15p的定位很重要，并且通过这种相互作用，Sec15p可能在整合Sec4p与早期极性建立机制组成部分之间的信号中发挥关键作用。这反过来又有助于协调分泌途径和分化芽生长。
localization of green fluorescent protein (GFP)-tagged Sec15 is affected, especially in the early stage of bud growth. In addition, Sec15-1p, which is Spatial regulation of the secretory machinery is essential for the formation of a new bud in Saccharomyces cerevisiae. Yet, the mechanisms underlying cross-talk between the secretory and the cell-polarity-establishment machineries have not been fully elucidated. Here, we report that Sec15p, a subunit of the exocyst complex, might provide one line of communication. Not only is Sec15p an effector of the rab protein Sec4p, the master regulator of post-Golgi trafficking, but it also interacts with components of the polarity-establishment machinery. We have demonstrated a direct physical interaction between Sec15p and Bem1p, a protein involved in the Cdc42p-mediated polarity-establishment pathway, confirming a prior two-hybrid study. When this interaction is compromised, as in the case of cells lacking the N-terminal 138 residues of Bem1p, including the first Src-homology 3 (SH3) domain, the localization of green fluorescent protein (GFP)-tagged Sec15 is affected, especially in the early stage of bud growth. In addition, Sec15-1p, which is defective in Bem1p binding, mislocalizes along with Sec8p, another exocyst subunit. Overall, our evidence suggests that the interaction of Sec15p with Bem1p is important for Sec15p localization at the early stage of bud growth and, through this interaction, Sec15p might play a crucial role in integrating the signals between Sec4p and the components of the early-polarity-establishment machinery. This, in turn, helps to coordinate the secretory pathway and polarized bud growth.