Two domains of p80 katanin regulate microtubule severing and spindle pole targeting by p60 katanin.
Two domains of p80 katanin regulate microtubule severing and spindle pole targeting by p60 katanin.
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DOI：
10.1242/jcs.113.9.1623
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发表时间：
2000-05
影响因子：
4
通讯作者：
K. McNally;O. A. Bazirgan;F. McNally
中科院分区：
文献类型：
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作者：
K. McNally;O. A. Bazirgan;F. McNally
有丝分裂纺锤体的组装和功能需要许多微管结合蛋白的活性。一些微管结合蛋白在体外结合微管，但不与间期细胞中的微管共定位。相反，这些蛋白质与有丝分裂纺锤体的特定亚区相关。Katanin是一种异源二聚体微管切割ATP酶，定位于有丝分裂纺锤体两极。在本文中，我们证明了人p60 katanin和人p80 katanin的C-末端结构域都结合微管在体外。这两种蛋白质的结合导致体外微管亲和力增加和微管切断活性增加。这些亚基在转染的HeLa细胞中的关联增加微管分解活性并靶向纺锤体极。p80 katanin的N-末端WD 40结构域作为微管分解活性的负调节剂，并且可能通过与另一种纺锤极蛋白的相互作用，也是纺锤极定位所需的。这些结果支持了一个模型，其中katanin通过p60亚基的直接微管结合和WD 40结构域与未知蛋白之间的相互作用的组合靶向纺锤体极。我们认为p80的两个结构域在体内精确调节katanin的活性中是必不可少的。
The assembly and function of the mitotic spindle requires the activity of a number of microtubule-binding proteins. Some microtubule-binding proteins bind microtubules in vitro but do not co-localize with microtubules in interphase cells. Instead these proteins associate with specific subregions of the mitotic spindle. Katanin, a heterodimeric microtubule-severing ATPase, is found localized at mitotic spindle poles. In this paper we demonstrate that human p60 katanin and the C-terminal domain of human p80 katanin both bind microtubules in vitro. Association of these two proteins results in an increased microtubule affinity and increased microtubule-severing activity in vitro. Association of these subunits in transfected HeLa cells increases microtubule disassembly activity and targeting to spindle poles. The N-terminal WD40 domain of p80 katanin acts as a negative regulator of microtubule disassembly activity and is also required for spindle pole localization, possibly through interactions with another spindle-pole protein. These results support a model in which katanin is targeted to spindle poles through a combination of direct microtubule binding by the p60 subunit and through interactions between the WD40 domain and an unknown protein. We propose that both domains of p80 are essential in precisely regulating katanin's activity in vivo.