Clathrin’s adaptor interaction sites are repurposed to stabilize microtubules during mitosis
Clathrin’s adaptor interaction sites are repurposed to stabilize microtubules during mitosis
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DOI：
10.1083/jcb.201907083
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发表时间：
2019-08
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通讯作者：
Arnaud Rondelet;Yu-Chih Lin;Divya Singh;A. T. Porfetye;H. C. Thakur;Andreas Hecker;Pia Brinkert;Nadine Schmidt;Shweta Bendre;Franziska Müller;Per O. Widlund;Tanja Bange;M. Hiller;I. Vetter;A. Bird
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作者：
Arnaud Rondelet;Yu-Chih Lin;Divya Singh;A. T. Porfetye;H. C. Thakur;Andreas Hecker;Pia Brinkert;Nadine Schmidt;Shweta Bendre;Franziska Müller;Per O. Widlund;Tanja Bange;M. Hiller;I. Vetter;A. Bird
网格蛋白在确保有丝分裂纺锤体稳定性和有效的染色体排列中起着重要作用，独立于其在囊泡运输中的功能。虽然网格蛋白明确定位于有丝分裂纺锤体和着丝纤维微管束，但其稳定微管的机制仍然是难以捉摸的。本研究表明，在有丝分裂过程中，网格蛋白重链（CHC）上的网格蛋白接头相互作用位点被重新利用，直接将微管稳定蛋白GTSE1招募到有丝分裂纺锤体中。结构分析表明，GTSE1上的多个网格蛋白盒基序与CHC上不同的网格蛋白接头相互作用位点直接相互作用，其结构类似于膜附近的衔接蛋白与CHC之间的相互作用。细胞中这种相互作用的特异性破坏将GTSE1从纺锤体中释放出来，并导致染色体排列缺陷。令人惊讶的是，这种破坏会导致星状微管的不稳定，但不会导致着丝点-微管的附着，由此产生的染色体排列缺陷是由于染色体连接失败而独立于着丝点-微管的附着稳定性。最后，我们发现GTSE1通过网格蛋白募集到纺锤体中，通过抑制微管解聚合酶MCAK的活性来稳定微管并促进染色体聚集。因此，这项工作揭示了网格蛋白在稳定非着丝点纤维微管以支持染色体聚集方面的新作用。这种作用是通过CHC与GTSE1的网格蛋白接头型相互作用来实现的，首次定义了有丝分裂过程中这种内吞相互作用机制的重要用途。
Clathrin plays an important role to ensure mitotic spindle stability and efficient chromosome alignment, independently of its well-characterized functions in vesicle trafficking. While clathrin clearly localizes to the mitotic spindle and kinetochore-fiber microtubule bundles, the mechanisms by which clathrin stabilizes microtubules have remained elusive. Here we show that clathrin adaptor interaction sites on clathrin heavy chain (CHC) are repurposed during mitosis to directly recruit the microtubule-stabilizing protein GTSE1 to the mitotic spindle. Structural analyses reveal that multiple clathrin-box motifs on GTSE1 interact directly with different clathrin adaptor interaction sites on CHC, in a manner structurally analogous to that which occurs between adaptor proteins and CHC near membranes. Specific disruption of this interaction in cells releases GTSE1 from spindles and causes defects in chromosome alignment. Surprisingly, this disruption causes destabilization of astral microtubules, but not kinetochore-microtubule attachments, and the resulting chromosome alignment defect is due to a failure of chromosome congression independent of kinetochore-microtubule attachment stability. Finally, we show that GTSE1 recruited to the spindle by clathrin stabilizes microtubules and promotes chromosome congression by inhibiting the activity of the microtubule depolymerase MCAK. This work thus uncovers a novel role of clathrin to stabilize non-kinetochore-fiber microtubules to support chromosome congression. This role is carried out via clathrin adaptor-type interactions of CHC with GTSE1, defining for the first time an important repurposing of this endocytic interaction mechanism during mitosis.