A complex of Cdc4p, Skp1p, and Cdc53p/cullin catalyzes ubiquitination of the phosphorylated CDK inhibitor Sic1p
A complex of Cdc4p, Skp1p, and Cdc53p/cullin catalyzes ubiquitination of the phosphorylated CDK inhibitor Sic1p
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DOI：
10.1016/s0092-8674(00)80404-3
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发表时间：
1997-10-17
期刊：
影响因子：
64.5
通讯作者：
Deshaies, RJ
中科院分区：
文献类型：
--
作者：
Feldman, RMR;Correll, CC;Deshaies, RJ
在酿酒酵母中，G1/S转变需要CDC4P，CDC34P，CDC53P，SKP1P和CLN/CDC28P Cyclin依赖性激酶（CDK）。这些蛋白被认为可以促进S期CDK抑制剂SIC1P的蛋白水解灭活。我们在这里表明CDC4P，CDC53P和SKP1P组装成名为SCFCDC4P的泛素连接酶配合物。混合在一起时，SCFCDC4P子单元，E1酶，E2酶CDC34P和泛素足以重新建立CDK磷酸化的SIC1P的泛素化。磷酸化的SIC1P底物是通过与CDC4P/SKP1P亚复合物结合而专门针对泛素化的。综上所述，这些数据阐明了萌芽酵母中G1/s转变的分子基础，并提出了真核生物中磷酸化靶向泛素化的一般机制。
In S. cerevisiae, the G1/S transition requires Cdc4p, Cdc34p, Cdc53p, Skp1p, and the Cln/Cdc28p cyclin-dependent kinase (Cdk). These proteins are thought to promote the proteolytic inactivation of the S-phase Cdk inhibitor Sic1p. We show here that Cdc4p, Cdc53p, and Skp1p assemble into a ubiquitin ligase complex named SCFCdc4p. When mixed together, SCFCdc4p sub- units, E1 enzyme, the E2 enzyme Cdc34p, and ubiquitin are sufficient to reconstitute ubiquitination of Cdk-phosphorylated Sic1p. Phosphorylated Sic1p substrate is specifically targeted for ubiquitination by binding to a Cdc4p/Skp1p subcomplex. Taken together, these data illuminate the molecular basis for the G1/S transition in budding yeast and suggest a general mechanism for phosphorylation-targeted ubiquitination in eukaryotes.