Myosin-II tails confer unique functions in Schizosaccharomyces pombe:: Characterization of a novel myosin-II tail
Myosin-II tails confer unique functions in Schizosaccharomyces pombe:: Characterization of a novel myosin-II tail
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DOI：
10.1091/mbc.11.1.79
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发表时间：
2000-01-01
影响因子：
3.3
通讯作者：
Pollard, TD
中科院分区：
文献类型：
--
作者：
Bezanilla, M;Pollard, TD
粟酒裂殖酵母具有两种肌球蛋白-II，Myo 2 p和Myp 2 p，它们在胞质分裂期间都集中在卵裂沟中。我们研究了突变型肌球蛋白-II菌株的表型，以检查这些肌球蛋白在细胞中是否具有重叠的功能。myo（2+）是必需的。myp（2+）不能挽救myo（2+）的损失，即使在升高的表达水平下。在特定的营养条件下需要myp（2+）;因此myo（2+）在这些条件下不能拯救。对嵌合体的研究表明，是尾部而不是结构相似的头部决定了myp（2+）和myo（2+）的基因特异性功能。Myo 2 p尾是棒状卷曲螺旋二聚体，与其他肌球蛋白II尾一样在低盐条件下聚集。Myp 2 p尾在高盐中是单体的，并且在低盐中不溶。全长Myp 2 p尾部和较小子域的生物物理性质表明，两个预测的卷曲螺旋区域折叠回自身，形成棒状反平行卷曲螺旋。这表明Myp 2 p是第一个只有一个头部的II型肌球蛋白。Myp 2 p尾的C-末端三分之二对于体内功能是必需的，并且可以与盐响应途径的组分相互作用。
Schizosaccharomyces pombe has two myosin-IIs, Myo2p and Myp2p, which both concentrate in the cleavage furrow during cytokinesis. We studied the phenotype of mutant myosin-II strains to examine whether these myosins have overlapping functions in the cell. myo(2+) is essential. myp(2+) cannot rescue loss of myo(2+) even at elevated levels of expression. myp(2+) is required under specific nutritional conditions; thus myo(2+) cannot rescue under these conditions. Studies with chimeras show that the tails rather than the structurally similar heads determine the gene-specific functions of myp(2+) and myo(2+). The Myo2p tail is a rod-shaped coiled-coil dimer that aggregates in low salt like other myosin-II tails. The Myp2p tail is monomeric in high salt and is insoluble in low salt. Biophysical properties of the full-length Myp2p tail and smaller subdomains indicate that two predicted coiled-coil regions fold back on themselves to form a rod-shaped antiparallel coiled coil. This suggests that Myp2p is the first type II myosin with only one head. The C-terminal two-thirds of Myp2p tail are essential for function in vivo and may interact with components of the salt response pathway.