Cell Signaling Technology

Product Pathways - Metabolism

Phospho-IRS-1 (Ser332/336) Antibody #2580

Applications Reactivity Sensitivity MW (kDa) Source
W R (H) (M) Transfected Only 180 Rabbit

Applications Key:  W=Western Blotting
Reactivity Key:  H=Human  M=Mouse  R=Rat
Species cross-reactivity is determined by western blot. Species enclosed in parentheses are predicted to react based on 100% sequence homology.

Protocols

Specificity / Sensitivity

Phospho-IRS-1 (Ser332/336) Antibody detects transfected levels of IRS-1 when phosphorylated at Ser332/336. It also detects IRS-1 protein when singly phosphorylated at Ser332 or Ser336 of human IRS-1. This antibody does not cross-react with other related phosphoproteins.

Source / Purification

Polyclonal antibodies are produced by immunizing animals with a synthetic phosphopeptide corresponding to residues surrounding Ser332/336 of mouse IRS-1 (equivalent to Ser337/341 of human IRS-1). Antibodies are purified by peptide affinity chromatography.

Western Blotting

Western Blotting

Western blot analysis of cell extracts from CHO cells overexpressing insulin receptor and IRS-1, untreated or treated with insulin, using Phospho-IRS-1 (Ser332/336) Antibody (upper and middle) or IRS-1 Antibody #2382 (lower). The middle blot was treated with calf intestinal phosphatase (CIP) before antibody probing.

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).

GSK-3-mediated IRS-1 serine phosphorylation leads to inhibition of insulin-stimulated IRS-1 signaling. Ser332 and Ser336 of IRS-1 are situated in a glycogen synthase kinase-3 (GSK-3) consensus motif (SXXXS), and it has been shown that Ser332 is the actual GSK-3 phosphorylation site while Ser336 provides a " priming" site necessary for GSK-3 action (11).

  1. Sun, X.J. et al. (1991) Nature 352, 73-77.
  2. Sun, X.J. et al. (1992) J. Biol. Chem. 267, 22662-22672.
  3. Myers Jr., M.G. et al. (1993) Endocrinology 132, 1421-1430.
  4. Wang, L.M. et al. (1993) Science 261, 1591-1594.
  5. Rui, L. et al. (1997) J. Clin. Invest. 107, 181-189.
  6. Gao, Z. et al. (2002) J. Biol. Chem. 277, 48115-48121.
  7. Horike, N. et al. (2003) J. Biol. Chem. 278, 18440-18447.
  8. Ozes, O.N. et al. (2001) Proc. Natl. Acad. Sci. USA 98, 4640-4645.
  9. De Fea, K. and Ruth, R.A. (1997) Biochemistry 36, 12939-12947.
  10. Li, Y. et al. (2004) J. Biol. Chem. 279, 45304-45307.
  11. Liberman, Z. and Eldar-Finkelman, H. (2005) J. Biol. Chem. 280, 4422-4428.

Application References

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For Research Use Only. Not For Use In Diagnostic Procedures.

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