The PAG gene product, a stress-induced protein with antioxidant properties, is an Abl SH3-binding protein and a physiological inhibitor of c-Abl tyrosine kinase activity.

Biochemical and genetic evidence suggests that the tyrosine kinase activity of c-Abl is tightly regulated in vivo by a cellular factor binding to the Src homology 3 (SH3) domain of Abl. We used the yeast two-hybrid system to identify a gene, PAG, whose protein product (Pag) interacts specifically with the ...
Abl SH3 domain. Pag, also known as macrophage 23-kD stress protein (MSP23), is a member of a novel family of proteins with antioxidant activity implicated in the cellular response to oxidative stress and in control of cell proliferation and differentiation. In a co-expression assay, Pag associates with c-Abl in vivo and inhibits tyrosine phosphorylation induced by overexpression of c-Abl. Inhibition requires the Abl SH3 and kinase domains and is not observed with other Abl SH3-binding proteins. Expression of Pag also inhibits the in vitro kinase activity of c-Abl, but not SH3-mutated Abl or v-Abl. When transfected in NIH-3T3 cells, Pag is localized to nucleus and cytoplasm and rescues the cytostatic effect induced by c-Abl. These observations suggest Pag is a physiological inhibitor of c-Abl in vivo.
Mesh Terms:
Amino Acid Sequence, Animals, Antioxidants, Cell Line, Cell Nucleus, Cloning, Molecular, Cytoplasm, Gene Expression Regulation, Heat-Shock Proteins, Humans, Mice, Molecular Sequence Data, Oncogene Proteins v-abl, Oxidative Stress, Peroxidases, Peroxiredoxins, Phosphotyrosine, Protein-Tyrosine Kinases, Proto-Oncogene Proteins c-abl, Sequence Analysis, DNA, Transfection, src Homology Domains
Genes Dev.
Date: Oct. 01, 1997
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