A yeast two-hybrid study of human p97/Gab2 interactions with its SH2 domain-containing binding partners.
p97/Gab2 is a recently characterized member of a large family of scaffold proteins that play essential roles in signal transduction. Gab2 becomes tyrosine-phosphorylated in response to a variety of growth factors and forms multimolecular complexes with SH2 domain-containing signaling molecules such as the p85-regulatory subunit of the phosphoinositide-3-kinase (p85-PI3K), the tyrosine phosphatase SHP-2 and the adapter protein CrkL. To characterize the interactions between Gab2 and its SH2-containing binding partners, we designed a modified yeast two-hybrid system in which the Lyn tyrosine kinase is expressed in a regulated manner in yeast. Using this assay, we demonstrated that p97/Gab2 specifically interacts with the SH2 domains of PI3K, SHP-2 and CrkL. Interaction with p85-PI3K is mediated by tyrosine residues Y452, Y476 and Y584 of Gab2, while interaction with SHP-2 depends exclusively on tyrosine Y614. CrkL interaction is mediated by its SH2 domain recognizing Y266 and Y293, despite the latter being in a non-consensus (YTFK) environment.
Pubmed ID: 11334882 RIS Download
Adaptor Proteins, Signal Transducing | Cell Line | Humans | Intracellular Signaling Peptides and Proteins | Nuclear Proteins | Peptides | Phosphatidylinositol 3-Kinases | Phosphoproteins | Phosphorylation | Phosphotyrosine | Protein Tyrosine Phosphatase, Non-Receptor Type 11 | Protein Tyrosine Phosphatase, Non-Receptor Type 6 | Protein Tyrosine Phosphatases | SH2 Domain-Containing Protein Tyrosine Phosphatases | Saccharomyces cerevisiae | Two-Hybrid System Techniques | src Homology Domains