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Proteomic screen finds pSer/pThr-binding domain localizing Plk1 to mitotic substrates
Andrew E H Elia1, Lewis C Cantley, Michael B Yaffe
1Center for Cancer Research, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Science (New York, N.Y.)
|February 22, 2003
Summary
Researchers identified a specific binding motif for the polo-box domain (PBD) of polo-like kinase 1 (Plk1). This discovery explains how Plk1 kinase localizes to cellular sites via Cdk phosphorylation, targeting its substrates.
Area of Science:
- Molecular Biology
- Cell Signaling
- Proteomics
Background:
- Kinase-dependent signaling pathways are crucial for cellular functions.
- Phosphorylation plays a key role in regulating these pathways.
- Identifying specific protein-protein interactions mediated by phosphorylation is essential for understanding cellular regulation.
Purpose of the Study:
- To develop a proteomic method for identifying phosphopeptide binding domains.
- To investigate the binding specificity of the polo-box domain (PBD) of polo-like kinase 1 (Plk1).
- To elucidate the mechanism of Plk1 localization and substrate targeting.
Main Methods:
- Utilized an immobilized library of degenerate phosphopeptides biased toward specific kinase phosphorylation motifs.
- Applied this approach to study cyclin-dependent kinases (Cdks).
- Isolated and characterized the phospho-binding domains interacting with phosphorylated substrates.
Main Results:
- Identified the polo-box domain (PBD) of Plk1 as a specific phosphoserine (pSer) or phosphothreonine (pThr) binding domain.
- Determined the optimal binding motif for the Plk1 PBD.
- Demonstrated that a phosphopeptide with the optimal motif disrupts PBD-substrate binding and centrosomal localization.
Conclusions:
- The Plk1 PBD specifically binds to phosphopeptides containing a defined motif.
- This interaction is regulated by Cdk phosphorylation.
- Provides a structural mechanism for Plk1 localization and substrate targeting within cells.
