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Specificity of the anaphase-promoting complex: a single-molecule study.

ABSTRACT: Biological processes require specific enzymatic reactions, paradoxically involving short recognition sequences. As an example, cell-cycle timing depends on a sequence of ubiquitylation events mediated by the anaphase-promoting complex (APC) based on short redundant motifs. To understand the origin of specificity, we designed single-molecule fluorescence assays that capture transient ubiquitylation reactions. We find that the APC-mediated ubiquitylation involves a highly processive initial reaction on the substrate, followed by multiple encounters and reactions at a slower rate. The initial ubiquitylation greatly enhances the substrate's binding affinity in subsequent reactions, by both increasing the on-rate and decreasing the off-rate. We postulate that these cycles of positive feedback enable high specificity for substrates with short recognition motifs in a complex cellular environment.

SUBMITTER: Lu Y

PROVIDER: S-EPMC4449139 | biostudies-literature | 2015 Apr

REPOSITORIES: biostudies-literature

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Specificity of the anaphase-promoting complex: a single-molecule study.

Lu Ying Y Wang Weiping W Kirschner Marc W MW

Science (New York, N.Y.) 20150409 6231

Biological processes require specific enzymatic reactions, paradoxically involving short recognition sequences. As an example, cell-cycle timing depends on a sequence of ubiquitylation events mediated by the anaphase-promoting complex (APC) based on short redundant motifs. To understand the origin of specificity, we designed single-molecule fluorescence assays that capture transient ubiquitylation reactions. We find that the APC-mediated ubiquitylation involves a highly processive initial reacti ...[more]

PMID: 25859049

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