Phospho-IRS-1 (Tyr895) Antibody detects transfected levels of IRS-1 only when phosphorylated at Tyr895. The antibody may cross-react with other activated receptor tyrosine kinases (RTKs) and docking proteins.
Source / Purification
Polyclonal antibodies are produced by immunizing animals with a synthetic phosphopeptide corresponding to residues surrounding Tyr896 of human IRS-1. Antibodies are purified by protein A and peptide affinity chromatography.
Background
Insulin receptor substrate 1 (IRS-1) is one of the major substrates of the insulin receptor kinase (1). IRS-1 contains multiple tyrosine phosphorylation motifs that serve as docking sites for SH2-domain containing proteins that mediate the metabolic and growth-promoting functions of insulin (2-4). IRS-1 also contains over 30 potential serine/threonine phosphorylation sites. Ser307 of IRS-1 is phosphorylated by JNK (5) and IKK (6) while Ser789 is phosphorylated by SIK-2, a member of the AMPK family (7). The PKC and mTOR pathways mediate phosphorylation of IRS-1 at Ser612 and Ser636/639, respectively (8,9). Phosphorylation of IRS-1 at Ser1101 is mediated by PKCθ and results in an inhibition of insulin signaling in the cell, suggesting a potential mechanism for insulin resistance in some models of obesity (10).
Phosphorylation of Tyr895 in IRS-1 provides a binding site for Grb2, which mediates the downstream signaling leading to MAP kinase activation and mitogenesis (11).