Kashina A S, Baskin R J, Cole D G, Wedaman K P, Saxton W M, Scholey J M
Section of Molecular and Cellular Biology, University of California, Davis 95616, USA.
Nature. 1996 Jan 18;379(6562):270-2. doi: 10.1038/379270a0.
Chromosome segregation during mitosis depends on the action of the mitotic spindle, a self-organizing, bipolar protein machine which uses microtubules (MTs) and their associated motors. Members of the BimC subfamily of kinesin-related MT-motor proteins are believed to be essential for the formation and functioning of a normal bipolar spindle. Here we report that KRP130, a homotetrameric BimC-related kinesin purified from Drosophila melanogaster embryos, has an unusual ultrastructure. It consists of four kinesin-related polypeptides assembled into a bipolar aggregate with motor domains at opposite ends, analogous to a miniature myosin filament. Such a bipolar 'minifilament' could crosslink spindle MTs and slide them relative to one another. We do not know of any other MT motors that have a bipolar structure.
有丝分裂过程中的染色体分离依赖于有丝分裂纺锤体的作用,有丝分裂纺锤体是一种自组织的双极蛋白质机器,它利用微管(MTs)及其相关的马达蛋白。驱动蛋白相关的微管马达蛋白的BimC亚家族成员被认为对于正常双极纺锤体的形成和功能至关重要。在此我们报告,KRP130是一种从黑腹果蝇胚胎中纯化出来的同四聚体BimC相关驱动蛋白,它具有不同寻常的超微结构。它由四条驱动蛋白相关多肽组装成一个双极聚集体,其马达结构域位于相对的两端,类似于一条微型肌球蛋白丝。这样一个双极“微丝”可以交联纺锤体微管并使它们相互滑动。我们不知道还有任何其他具有双极结构的微管马达蛋白。