Mechanisms of pseudosubstrate inhibition of the anaphase promoting complex by Acm1
Mechanisms of pseudosubstrate inhibition of the anaphase promoting complex by Acm1
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DOI：
10.1038/emboj.2011.90
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发表时间：
2011-05-04
期刊：
影响因子：
11.4
通讯作者：
Solomon, Mark J.
中科院分区：
文献类型：
--
作者：
Burton, Janet L.;Xiong, Yong;Solomon, Mark J.
后期促进复合物（APC）是一种泛素连接酶，可促进26 S蛋白酶体降解细胞周期调节因子。Cdc 20和Cdh 1是含有WD 40的APC共激活剂，其结合底物内的破坏盒（DB）和KEN盒以将它们募集到APC用于泛素化。Acm 1是一种APC（Cdh 1）抑制剂，它利用DB和KEN盒结合Cdh 1并阻止底物结合，尽管Acm 1本身不是底物。我们研究了APC底物与抑制剂的区别。我们鉴定了与Cdh 1相互作用的Acm 1 A-基序，并且与DB和KEN盒一起是APC（Cdh 1）抑制所需的。遗传筛选鉴定了对Acm 1 A-基序相互作用和抑制重要的Cdh 1 WD 40结构域残基，其似乎位于对DB识别重要的Cdh 1残基附近。Acm 1内的特异性赖氨酸插入突变促进了APC（Cdh 1）对Acm 1的泛素化，而从APC底物Hsl 1去除赖氨酸将其转化为有效的APC（Cdh 1）抑制剂。这些发现表明，Cdh 1的紧密结合加上可遍在化赖氨酸的不可及性有助于APC（Cdh 1）的假底物抑制。The EMBO Journal（2011）30，1818-1829. doi：10.1038/daj.2011.90; 2011年4月1日在线发布
The anaphase promoting complex (APC) is a ubiquitin ligase that promotes the degradation of cell-cycle regulators by the 26S proteasome. Cdc20 and Cdh1 are WD40-containing APC co-activators that bind destruction boxes (DB) and KEN boxes within substrates to recruit them to the APC for ubiquitination. Acm1 is an APC(Cdh1) inhibitor that utilizes a DB and a KEN box to bind Cdh1 and prevent substrate binding, although Acm1 itself is not a substrate. We investigated what differentiates an APC substrate from an inhibitor. We identified the Acm1 A-motif that interacts with Cdh1 and together with the DB and KEN box is required for APC(Cdh1) inhibition. A genetic screen identified Cdh1 WD40 domain residues important for Acm1 A-motif interaction and inhibition that appears to reside near Cdh1 residues important for DB recognition. Specific lysine insertion mutations within Acm1 promoted its ubiquitination by APC(Cdh1) whereas lysine removal from the APC substrate Hsl1 converted it into a potent APC(Cdh1) inhibitor. These findings suggest that tight Cdh1 binding combined with the inaccessibility of ubiquitinatable lysines contributes to pseudosubstrate inhibition of APC(Cdh1). The EMBO Journal (2011) 30, 1818-1829. doi:10.1038/emboj.2011.90; Published online 1 April 2011