Mutational analysis of capping protein function in Saccharomyces cerevisiae.
Mutational analysis of capping protein function in Saccharomyces cerevisiae.
复制标题
酿酒酵母加帽蛋白功能的突变分析。
DOI：
10.1091/mbc.7.1.1
复制
发表时间：
1996
影响因子：
3.3
通讯作者：
Cooper,JA
中科院分区：
文献类型：
--
作者：
Sizonenko,GI;Karpova,TS;Gattermeir,DJ;Cooper,JA
为了研究肌动蛋白加帽蛋白 (CP) 的生理功能和结构相关性，我们分析了 CAP1 和 CAP2 的定点突变，CAP1 和 CAP2 编码酿酒酵母中 CP 的 α 和 β 亚基。尽管细胞中存在突变蛋白，但四个不同区域的突变导致体内 CP 功能丧失。三个区域的突变导致所有方面的功能完全丧失，包括肌动蛋白分布、sac6 的活力以及 CP 到肌动蛋白皮质斑块的定位。第四个区域的突变仅导致肌动蛋白线的一种功能部分丧失。一些突变保留了功能并表现出完整的野生型表型，而一些突变导致蛋白质完全丧失，从而丧失功能。可以解释这些结果的最简单的假设是，所有体内功能都需要单一的生化特性。这种生化特性很可能与肌动蛋白丝结合，因为非功能性突变 CP 不再与体内肌动蛋白丝共定位，并且通过体外纯化蛋白的研究已经充分确定了 CP 与肌动蛋白丝的直接结合。该分析不能排除更复杂的假设，包括对功能重要的其他生化特性的存在。
To investigate physiologic functions and structural correlates for actin capping protein (CP), we analyzed site-directed mutations in CAP1 and CAP2, which encode the alpha and beta subunits of CP in Saccharomyces cerevisiae. Mutations in four different regions caused a loss of CP function in vivo despite the presence of mutant protein in the cells. Mutations in three regions caused a complete loss of all aspects of function, including the actin distribution, viability with sac6, and localization of CP to actin cortical patches. Mutation of the fourth region led to partial loss of only one function-formation of actin cables. Some mutations retained function and exhibited the complete wild-type phenotype, and some mutations led to a complete loss of protein and therefore loss of function. The simplest hypothesis that can explain these results is that a single biochemical property is necessary for all in vivo functions. This biochemical property is most likely binding to actin filaments, because the nonfunctional mutant CPs no longer co-localize with actin filaments in vivo and because direct binding of CP to actin filaments has been well established by studies with purified proteins in vitro. More complex hypotheses, involving the existence of additional biochemical properties important for function, cannot be excluded by this analysis.