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Differential association of cellular proteins with family protein-tyrosine kinases
O Sartor1, J H Sameshima, K C Robbins
1Laboratory of Cellular Development and Oncology, National Institute of Dental Research, National Institutes of Health, Bethesda, Maryland 20892.
Abstract:
We have sought to identify candidate substrates for src family protein-tyrosine kinases potentially important for transformation. Transfected NIH/3T3 cells, each overexpressing a normal or activated version of the fyn, fgr, or src translational product, were examined using antibody to phosphotyrosine as a probe. Expression of each cDNA induced similar but distinct patterns of tyrosine phosphorylated cellular proteins, with the extent of phosphorylation being greatest in cells expressing an activated kinase. A 70-kDa tyrosine-phosphorylated protein was found to associate with the activated fyn gene product. A protein designated p130, tyrosine phosphorylated in vitro, and in vivo, was found to physically associate with the activated product of each src family gene examined. Physical interaction of three different highly transforming tyrosine kinases with a common cellular protein suggests that p130 may play an important role in transformation induced by src family kinases.
Insights
Researchers identified p130 as a protein interacting with src family kinases. This interaction, involving tyrosine phosphorylation, suggests p130
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Background:
- Src family kinases are critical regulators of cellular processes.
- Dysregulation of src family kinases is implicated in cancer development.
- Identifying their substrates is key to understanding transformation mechanisms.
Purpose of the Study:
- To identify potential substrates of src family protein-tyrosine kinases involved in cellular transformation.
- To investigate the interaction of specific src family kinases (fyn, fgr, src) with cellular proteins.
Main Methods:
- Utilized NIH/3T3 cells overexpressing normal or activated forms of fyn, fgr, and src.
- Employed antibody to phosphotyrosine to detect tyrosine-phosphorylated proteins.
- Performed co-immunoprecipitation to assess protein-protein interactions.
Main Results:
- Overexpression of src family kinases induced distinct patterns of tyrosine-phosphorylated proteins.
- A 70-kDa protein was found to associate with activated Fyn.
- A protein designated p130 was tyrosine-phosphorylated and physically associated with activated products of fyn, fgr, and src.
Conclusions:
- p130 is a common cellular protein that interacts with activated src family kinases.
- The physical association of p130 with multiple transforming tyrosine kinases suggests its significant role in src family kinase-induced transformation.