Type II myosin heavy chain encoded by the myo2 gene composes the contractile ring during cytokinesis in Schizosaccharomyces pombe.
Type II myosin heavy chain encoded by the myo2 gene composes the contractile ring during cytokinesis in Schizosaccharomyces pombe.
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由 myo2 基因编码的 II 型肌球蛋白重链在粟酒裂殖酵母胞质分裂过程中组成收缩环。
DOI：
10.1083/jcb.137.6.1309
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发表时间：
1997-06-16
期刊：
影响因子：
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通讯作者：
Yamamoto M
中科院分区：
文献类型：
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作者：
Kitayama C;Sugimoto A;Yamamoto M
我们克隆了裂殖酵母myo 2基因，该基因编码II型肌球蛋白重链，凭借其促进裂殖酵母细胞二倍化的能力。myo 2基因在单个开放阅读框中编码1，526个氨基酸。Myo 2 p与常规II型肌球蛋白重链的头部结构域和卷曲螺旋尾部具有同源性，并携带ATP和肌动蛋白的推定结合位点。它还携带IQ基序，这是肌球蛋白轻链的假定结合位点。然而，Myo 2 p显然只携带一个IQ基序，而其他物种的对应物则有两个。在Myo 2 p的羧基端卷曲螺旋区有9个脯氨酸残基，它们应该破坏α-螺旋。因此，Myo 2 p作为II型肌球蛋白重链是相当不寻常的。myo 2的破坏抑制细胞增殖。myo 2 Δ细胞的间期肌动蛋白呈正常点状分布，但产生不规则的肌动蛋白环和间隔，细胞分离能力受损。Myo 2 p的过度生产也是致命的，显然阻止肌动蛋白的重新定位。在过表达Myo 2 p的细胞中，核分裂进行而没有肌动蛋白环形成和胞质分裂，从而产生具有哑铃形态的多核细胞。使用标记的Myo 2 p的分析显示，Myo 2 p与肌动蛋白共定位在收缩环中，表明Myo 2 p是环的组成部分，并负责其收缩。此外，遗传学证据表明，肌动蛋白-肌球蛋白系统可能与Ras途径相互作用，该途径调节S.粟酒
We cloned the myo2 gene of Schizosaccharomyces pombe, which encodes a type II myosin heavy chain, by virtue of its ability to promote diploidization in fission yeast cells. The myo2 gene encodes 1,526 amino acids in a single open reading frame. Myo2p shows homology to the head domains and the coiledcoil tail of the conventional type II myosin heavy chain and carries putative binding sites for ATP and actin. It also carries the IQ motif, which is a presumed binding site for the myosin light chain. However, Myo2p apparently carries only one IQ motif, while its counterparts in other species have two. There are nine proline residues, which should break α-helix, in the COOH-terminal coiled-coil region of Myo2p. Thus, Myo2p is rather unusual as a type II myosin heavy chain. Disruption of myo2 inhibited cell proliferation. myo2Δ cells showed normal punctate distribution of interphase actin, but they produced irregular actin rings and septa and were impaired in cell separation. Overproduction of Myo2p was also lethal, apparently blocking actin relocation. Nuclear division proceeded without actin ring formation and cytokinesis in cells overexpressing Myo2p, giving rise to multinucleated cells with dumbbell morphology. Analysis using tagged Myo2p revealed that Myo2p colocalizes with actin in the contractile ring, suggesting that Myo2p is a component of the ring and responsible for its contraction. Furthermore, genetic evidence suggested that the acto–myosin system may interact with the Ras pathway, which regulates mating and the maintenance of cell morphology in S. pombe.