Cyert M S
Department of Biological Sciences, Stanford University, Stanford, California 94305-5020, USA.
Annu Rev Genet. 2001;35:647-72. doi: 10.1146/annurev.genet.35.102401.091302.
Calmodulin, a small, ubiquitous Ca2+-binding protein, regulates a wide variety of proteins and processes in all eukaryotes. CMD1, the single gene encoding calmodulin in S. cerevisiae, is essential, and this review discusses studies that identified many of calmodulin's physiological targets and their functions in yeast cells. Calmodulin performs essential roles in mitosis, through its regulation of Nuf1p/Spc110p, a component of the spindle pole body, and in bud growth, by binding Myo2p, an unconventional class V myosin required for polarized secretion. Surprisingly, mutant calmodulins that fail to bind Ca2+ can perform these essential functions. Calmodulin is also required for endocytosis in yeast and participates in Ca2+-dependent, stress-activated signaling pathways through its regulation of a protein phosphatase, calcineurin, and the protein kinases, Cmk1p and Cmk2p. Thus, calmodulin performs important physiological functions in yeast cells in both its Ca2+-bound and Ca2+-free form.
钙调蛋白是一种小的、普遍存在的钙离子结合蛋白，在所有真核生物中调节多种蛋白质和过程。CMD1是酿酒酵母中编码钙调蛋白的唯一基因，是必需的，本综述讨论了确定钙调蛋白许多生理靶点及其在酵母细胞中功能的研究。钙调蛋白在有丝分裂中发挥重要作用，通过调节纺锤极体的一个组成部分Nuf1p/Spc110p，以及在芽生长中，通过结合Myo2p，一种极化分泌所需的非常规V类肌球蛋白。令人惊讶的是，未能结合钙离子的突变钙调蛋白可以执行这些基本功能。钙调蛋白在酵母的内吞作用中也是必需的，并通过调节蛋白磷酸酶钙调神经磷酸酶以及蛋白激酶Cmk1p和Cmk2p参与钙离子依赖性、应激激活的信号通路。因此，钙调蛋白以其结合钙离子和未结合钙离子的形式在酵母细胞中发挥重要的生理功能。
