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Updated: Aug 5, 2026
Identification of Kinase-substrate Pairs Using High Throughput Screening
Published on: August 29, 2015
Mapping of tyrosine kinase autophosphorylation sites with synthetic peptide substrates
1Howard Hughes Medical Institute, University of California, San Francisco.
Abstract:
Tyrosine phosphorylation is a key step in the regulation of many cellular events including signal transduction of stimulated growth factor receptor tyrosine kinases. Upon ligand activation, these proteins undergo dimerization and subsequent auto- and transphosphorylation events on specific tyrosine residues, which enables them to interact with several cellular signaling proteins. We have used synthetic peptides encompassing all the tyrosine residues of a tyrosine kinase and employed them as substrates in in vitro kinase reactions. Using this assay we have shown that short tyrosine-containing peptides derived from the cytoplasmic domain of the mouse platelet-derived growth factor beta receptor (PDGF-R) can serve as specific phosphorylation targets for the kinase. These peptides include 7 out of 8 tyrosines that are known auto- or transphosphorylation sites in vivo, as previously determined by peptide mapping and mutational analyses. We have also identified 10 additional tyrosine-containing peptides that are phosphorylated and represent possible novel auto- or transphosphorylation sites of PDGF-R. The presented method greatly simplifies the mapping of auto- or transphosphorylation sites in tyrosine kinases and provides a valuable tool in the analysis of signaling mechanisms involving these proteins.
Insights
Researchers developed a new method using synthetic peptides to identify tyrosine phosphorylation sites on growth factor receptors. This technique simplifies the analysis of tyrosine kinases and signaling pathways, revealing potential new phosphorylation sites on the platelet-derived growth factor beta receptor (PDGF-R).
Area of Science:
- Molecular Biology
- Cell Signaling
- Biochemistry
Background:
- Tyrosine phosphorylation regulates critical cellular events, including signal transduction initiated by growth factor receptor tyrosine kinases.
- Activated receptor tyrosine kinases dimerize and undergo auto- and transphosphorylation, creating docking sites for signaling proteins.
Purpose of the Study:
- To develop a simplified in vitro method for mapping tyrosine phosphorylation sites on tyrosine kinases.
- To identify novel auto- or transphosphorylation sites on the mouse platelet-derived growth factor beta receptor (PDGF-R).
Main Methods:
- Utilized synthetic peptides representing tyrosine residues of a tyrosine kinase as substrates in in vitro kinase reactions.
- Employed peptides derived from the cytoplasmic domain of the mouse PDGF-R to test kinase phosphorylation specificity.
Main Results:
- Demonstrated that short tyrosine-containing peptides from PDGF-R can be specifically phosphorylated by the kinase in vitro.
- Identified 10 novel tyrosine-containing peptides phosphorylated by the kinase, suggesting potential new auto- or transphosphorylation sites.
- Confirmed 7 known in vivo phosphorylation sites on PDGF-R using this peptide assay.
Conclusions:
- The synthetic peptide assay is an effective and simplified tool for mapping tyrosine kinase auto- and transphosphorylation sites.
- This method advances the analysis of signaling mechanisms involving receptor tyrosine kinases like PDGF-R.
