Specificity of the anaphase-promoting complex: a single-molecule study.
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.
Mesh Terms:
Anaphase-Promoting Complex-Cyclosome, Cell Cycle, Cyclin A, Cyclin B, Feedback, Physiological, Fluorescence, Fluorescent Dyes, HeLa Cells, Humans, Kinetics, Protein Binding, Protein Interaction Domains and Motifs, SMN Complex Proteins, Substrate Specificity, Ubiquitin, Ubiquitination
Anaphase-Promoting Complex-Cyclosome, Cell Cycle, Cyclin A, Cyclin B, Feedback, Physiological, Fluorescence, Fluorescent Dyes, HeLa Cells, Humans, Kinetics, Protein Binding, Protein Interaction Domains and Motifs, SMN Complex Proteins, Substrate Specificity, Ubiquitin, Ubiquitination
Science
Date: Apr. 10, 2015
PubMed ID: 25859049
View in: Pubmed Google Scholar
Download Curated Data For This Publication
242298
Switch View:
- Interactions 12