Henn Arnon, Sadot Einat
Faculty of Biology, Technion-Israel Institute of Technology, Haifa 3200003, Israel.
The Institute of Plant Sciences, Volcani Center, PO Box 6, Bet-Dagan 5025000, Israel.
Curr Opin Plant Biol. 2014 Dec;22:65-70. doi: 10.1016/j.pbi.2014.09.006. Epub 2014 Oct 2.
Myosins are molecular motors that move along actin-filament tracks. Plants express two main classes of myosins, myosin VIII and myosin XI. Along with their relatively conserved sequence and functions, plant myosins have acquired some unique features. Myosin VIII has the enzymatic characteristics of a tension sensor and/or a tension generator, similar to functions found in other eukaryotes. Interestingly, class XI plant myosins have gained a novel function that consists of propelling the exceptionally rapid cytoplasmic streaming. This specific class includes the fastest known translocating molecular motors, which can reach an extremely high velocity of about 60μms(-1). However, the enzymatic properties and mechanistic basis for these remarkable manifestations are not yet fully understood. Here we review recent progress in understanding the uniqueness of plant myosins, while emphasizing the unanswered questions.
肌球蛋白是沿着肌动蛋白丝轨道移动的分子马达。植物表达两类主要的肌球蛋白，即肌球蛋白VIII和肌球蛋白XI。除了具有相对保守的序列和功能外，植物肌球蛋白还具有一些独特的特征。肌球蛋白VIII具有张力传感器和/或张力发生器的酶学特性，类似于在其他真核生物中发现的功能。有趣的是，XI类植物肌球蛋白获得了一种新功能，即推动异常快速的细胞质流动。这一特定类别包括已知移动速度最快的分子马达，其速度可达到约60μm s-1的极高速度。然而，这些显著表现的酶学性质和机制基础尚未完全了解。在此，我们回顾了在理解植物肌球蛋白独特性方面的最新进展，同时强调了尚未解答的问题。
