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Oncogenes, Protein Tyrosine Kinases, and Signal Transduction
1Department of Microbiology, The Mount Sinai School of Medicine, New York, N.Y., USA.
Abstract:
Many oncogenes encode protein tyrosine kinases (PTKs). Oncogenic mutations of these genes invariably result in constitutive activation of these PTKs. Autophosphorylation of the PTKs and tyrosine phosphorylation of their cellular substrates are essential events for transmission of the mitogenic signal into cells. The recent discovery of the characteristic amino acid sequences, of the src homology domains 2 and 3 (SH2 and SH3), and extensive studies on proteins containing the SH2 and SH3 domains have revealed that protein tyrosine-phosphorylation of PTKs provides phosphotyrosine sites for SH2 binding and allows extracellular signals to be relayed into the nucleus through a chain of protein-protein interactions mediated by the SH2 and SH3 domains. Studies on oncogenes, PTKs and SH2/SH3-containing proteins have made a tremendous contribution to our understanding of the mechanisms for the control of cell growth, oncogenesis, and signal transduction. This review is intended to provide an outline of the most recent progress in the study of signal transduction by PTKs. Copyright 1994 S. Karger AG, Basel
Insights
Oncogenic protein tyrosine kinases (PTKs) transmit signals for cell growth. Their activation and interactions via SH2/SH3 domains are key to understanding oncogenesis and signal transduction.
Area of Science:
- Molecular Biology
- Cellular Signaling
- Oncogenesis
Background:
- Many oncogenes encode protein tyrosine kinases (PTKs).
- Mutations lead to constitutive PTK activation, crucial for cell signaling.
- PTK autophosphorylation and substrate phosphorylation transmit mitogenic signals.
Purpose of the Study:
- To review recent progress in signal transduction by PTKs.
- To highlight the role of SH2 and SH3 domains in signal relay.
- To connect PTK function to cell growth control and oncogenesis.
Main Methods:
- Review of studies on oncogenes, PTKs, and SH2/SH3-containing proteins.
- Analysis of protein-protein interactions mediated by SH2/SH3 domains.
- Examination of phosphotyrosine binding sites for SH2 domains.
Main Results:
- PTK activation is essential for signal transmission.
- SH2/SH3 domains mediate signal relay from extracellular signals to the nucleus.
- Protein tyrosine phosphorylation provides binding sites for SH2 domains.
Conclusions:
- Studies on PTKs and SH2/SH3 proteins advance understanding of cell growth control.
- PTKs play a central role in oncogenesis through signal transduction pathways.
- SH2/SH3-mediated interactions are critical for relaying cellular signals.