Augmin shapes the anaphase spindle for efficient cytokinetic furrow ingression and abscission.
Augmin shapes the anaphase spindle for efficient cytokinetic furrow ingression and abscission.
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DOI：
10.1091/mbc.e15-02-0101
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发表时间：
2016-03-01
影响因子：
3.3
通讯作者：
Goshima G
中科院分区：
文献类型：
--
作者：
Uehara R;Kamasaki T;Hiruma S;Poser I;Yoda K;Yajima J;Gerlich DW;Goshima G
微管成核调节剂Augmin的耗尽对纺锤体的扰动揭示了它对控制卵裂沟侵入以及胞质分裂完成的意想不到的贡献。这些是通过胞质分裂调节剂的非冗余靶向机制实现的。在分裂后期，微管（MT）的不同群体的形式，无论是中心体依赖或Augmin依赖的成核。这些不同的MT群体是否对胞质分裂有不同的功能，这在很大程度上仍然是未知的。在这里，我们表明，augmin依赖的MT的发展所需的两个沟侵入和脱落。Augmin耗竭减少了细胞赤道处的收缩环调节剂苯胺林的积累，但中心体MT足以介导沟槽处的RhoA激活。这种缺陷在收缩环组织，结合不完整的纺锤体极分离后期，导致受损的沟内移。在胞质分裂的后期阶段，星形MT在细胞间桥中形成束，但这些未能组装成一个集中的中间体结构，也没有建立与质膜的紧密联系，导致沟退化。因此，augmin依赖的acentrosomal MT和中心体MT有助于不同的胞质分裂因子的非冗余靶向机制，这是形成功能性收缩环和中间体所必需的。
Perturbations of the central spindle by depletion of a microtubule nucleation regulator, augmin, revealed its unexpected contributions to the control of cleavage furrow ingression, as well as to cytokinesis completion. These are achieved through nonredundant targeting mechanisms of cytokinesis regulators. During anaphase, distinct populations of microtubules (MTs) form by either centrosome-dependent or augmin-dependent nucleation. It remains largely unknown whether these different MT populations contribute distinct functions to cytokinesis. Here we show that augmin-dependent MTs are required for the progression of both furrow ingression and abscission. Augmin depletion reduced the accumulation of anillin, a contractile ring regulator at the cell equator, yet centrosomal MTs were sufficient to mediate RhoA activation at the furrow. This defect in contractile ring organization, combined with incomplete spindle pole separation during anaphase, led to impaired furrow ingression. During the late stages of cytokinesis, astral MTs formed bundles in the intercellular bridge, but these failed to assemble a focused midbody structure and did not establish tight linkage to the plasma membrane, resulting in furrow regression. Thus augmin-dependent acentrosomal MTs and centrosomal MTs contribute to nonredundant targeting mechanisms of different cytokinesis factors, which are required for the formation of a functional contractile ring and midbody.