肌球蛋白-1c将正在组装的肌动蛋白与细胞膜相连，以驱动代偿性内吞作用。
Myosin-1c couples assembling actin to membranes to drive compensatory endocytosis.
作者信息
Sokac Anna M, Schietroma Cataldo, Gundersen Cameron B, Bement William M
机构信息
Program in Cellular and Molecular Biology, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
出版信息
Dev Cell. 2006 Nov;11(5):629-40. doi: 10.1016/j.devcel.2006.09.002.
Compensatory endocytosis follows regulated exocytosis in cells ranging from eggs to neurons, but the means by which it is accomplished are unclear. In Xenopus eggs, compensatory endocytosis is driven by dynamic coats of assembling actin that surround and compress exocytosing cortical granules (CGs). We have identified Xenopus laevis myosin-1c (XlMyo1c) as a myosin that is upregulated by polyadenylation during meiotic maturation, the developmental interval that prepares eggs for fertilization and regulated CG exocytosis. Upon calcium-induced exocytosis, XlMyo1c is recruited to exocytosing CG membranes where actin coats then assemble. When XlMyo1c function is disrupted, actin coats assemble, but dynamic actin filaments are uncoupled from the exocytosing CG membranes such that coats do not compress, and compensatory endocytosis fails. Remarkably, there is also an increase in polymerized actin at membranes throughout the cell. We conclude that XlMyo1c couples polymerizing actin to membranes and so mediates force production during compensatory endocytosis.
从卵细胞到神经元的各类细胞中，补偿性内吞作用在调节性胞吐作用之后发生，但其实现方式尚不清楚。在非洲爪蟾卵中，补偿性内吞作用由动态的肌动蛋白组装衣被驱动，这些衣被围绕并压缩正在胞吐的皮质颗粒（CGs）。我们已鉴定出非洲爪蟾肌球蛋白-1c（XlMyo1c）是一种在减数分裂成熟过程中通过多聚腺苷酸化上调的肌球蛋白，减数分裂成熟是使卵子为受精和调节性CG胞吐作用做好准备的发育阶段。在钙诱导的胞吐作用发生时，XlMyo1c被招募到正在胞吐的CG膜上，随后肌动蛋白衣被在那里组装。当XlMyo1c的功能被破坏时，肌动蛋白衣被会组装，但动态的肌动蛋白丝与正在胞吐的CG膜解偶联，导致衣被无法压缩，补偿性内吞作用失败。值得注意的是，整个细胞的膜上聚合肌动蛋白也会增加。我们得出结论，XlMyo1c将聚合的肌动蛋白与膜偶联，从而在补偿性内吞作用期间介导力的产生。
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