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Regulation by the autophosphorylation site in overexpressed pp60c-src
T E Kmiecik1, P J Johnson, D Shalloway
1Department of Molecular and Cell Biology, Pennsylvania State University, University Park, 16802.
Molecular and Cellular Biology
|October 1, 1988
Summary
Overexpressed pp60c-src shows increased activity when phosphorylated at Tyr-416, especially when tyrosine phosphatase activity is inhibited. This suggests Tyr-416 phosphorylation transiently regulates pp60c-src activity in cells.
Area of Science:
- Biochemistry
- Molecular Biology
- Cell Signaling
Background:
- pp60c-src is a proto-oncogene tyrosine kinase.
- Its activity is regulated by phosphorylation.
- The role of Tyr-416 phosphorylation in pp60c-src activity is under investigation.
Purpose of the Study:
- To investigate the role of Tyr-416 phosphorylation in regulating pp60c-src activity in vivo.
- To determine if inhibiting tyrosine phosphatases affects pp60c-src activity and phosphorylation.
Main Methods:
- Overexpression of pp60c-src in cells.
- Incubation of cells with vanadate, a tyrosine phosphatase inhibitor.
- Isolation and kinase activity assay of pp60c-src.
- Site-directed mutagenesis of Tyr-416.
Main Results:
- Overexpressed pp60c-src showed increased specific kinase activity when isolated from vanadate-treated cells.
- Vanadate treatment led to increased Tyr-416 phosphorylation of pp60c-src.
- Mutagenesis studies indicated that Tyr-416 phosphorylation modulates the activity of pp60v-src.
Conclusions:
- Transient Tyr-416 phosphorylation is a key mechanism for modulating pp60c-src activity in vivo.
- Inhibition of tyrosine phosphatases enhances pp60c-src activity through Tyr-416 phosphorylation.
- These findings contribute to understanding the regulation of src-family kinases.