Cohesin cleavage by separase is enhanced by a substrate motif distinct from the cleavage site.
Cohesin cleavage by separase is enhanced by a substrate motif distinct from the cleavage site.
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与切割位点不同的底物基序增强了分离酶对粘连蛋白的切割。
DOI：
10.1038/s41467-019-13209-y
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发表时间：
2019
影响因子：
16.6
通讯作者：
Morgan,DavidO
中科院分区：
文献类型：
--
作者：
Rosen,LauraE;Klebba,JosephE;Asfaha,JonathanB;Ghent,ChloeM;Campbell,MelodyG;Cheng,Yifan;Morgan,DavidO
当半胱氨酸蛋白酶（分离酶）在中期到后期的转变时裂解粘连蛋白的 Scc1 亚基时，染色体分离开始。分离酶在中期之前被紧密结合的 securin 蛋白抑制，该蛋白含有阻断分离酶活性位点的假底物基序。为了研究分离酶底物特异性和调控，我们开发了一种用于生产重组、不含 securin 的人分离酶的系统。使用这种酶，我们在 Scc1 底物上鉴定了一个 LPE 基序，该基序与切割位点不同，并且是快速和特异性底物切割所必需的。 Securin 还包含一个保守的 LPE 基序，我们提供了该序列阻断 Scc1 LPE 基序的分离酶接合的证据。我们的结果表明，分离酶的快速粘连蛋白裂解需要活性位点外的底物对接相互作用。这种相互作用被 securin 阻断，从而提供了 securin 抑制粘连蛋白裂解的第二种机制。
Chromosome segregation begins when the cysteine protease, separase, cleaves the Scc1 subunit of cohesin at the metaphase-to-anaphase transition. Separase is inhibited prior to metaphase by the tightly bound securin protein, which contains a pseudosubstrate motif that blocks the separase active site. To investigate separase substrate specificity and regulation, here we develop a system for producing recombinant, securin-free human separase. Using this enzyme, we identify an LPE motif on the Scc1 substrate that is distinct from the cleavage site and is required for rapid and specific substrate cleavage. Securin also contains a conserved LPE motif, and we provide evidence that this sequence blocks separase engagement of the Scc1 LPE motif. Our results suggest that rapid cohesin cleavage by separase requires a substrate docking interaction outside the active site. This interaction is blocked by securin, providing a second mechanism by which securin inhibits cohesin cleavage.