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The PTB domain: a new protein module implicated in signal transduction
1Program in Molecular Biology and Cancer, Mount Sinai Hospital, Toronto, Ontario, Canada.
Trends in Biochemical Sciences
|July 1, 1995
Summary
Src homology 2 (SH2) domains bind phosphorylated proteins in signal transduction. A novel phosphotyrosine-binding (PTB) domain recognizes these proteins differently, impacting Ras activation.
Area of Science:
- Molecular Biology
- Cell Signaling
- Biochemistry
Background:
- Src homology 2 (SH2) domains are crucial for signal transduction pathways, particularly downstream of receptor tyrosine kinases.
- These domains facilitate the binding of cytoplasmic signaling proteins to phosphotyrosine-containing polypeptides, a key event in growth factor signaling.
Purpose of the Study:
- To identify and characterize novel phosphotyrosine-binding (PTB) domains involved in cellular signaling.
- To compare the binding characteristics of PTB domains with established SH2 domains.
Main Methods:
- Identification of a novel phosphotyrosine-binding (PTB) domain in the Shc adaptor protein.
- Comparative analysis of the structural and binding properties of PTB and SH2 domains.
Main Results:
- A novel PTB domain was identified in the amino terminus of the Shc adaptor molecule.
- PTB domains are longer than SH2 domains and recognize phosphotyrosine within the context of amino-terminal residues.
- SH2 domains recognize phosphotyrosine within the context of carboxy-terminal residues.
Conclusions:
- The newly identified PTB domain in Shc plays a role in Ras activation pathways.
- PTB and SH2 domains exhibit distinct phosphotyrosine recognition mechanisms, contributing to the specificity of signal transduction.