Cell Signaling Technology

Product Pathways - Metabolism

Phospho-IRS-1 (Ser318) (D51C3) Rabbit mAb #5610

Applications Reactivity Sensitivity MW (kDa) Isotype
W IP H M (R) Endogenous 180 Rabbit IgG

Applications Key:  W=Western Blotting  IP=Immunoprecipitation
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 (Ser318) (D51C3) Rabbit mAb recognizes endogenous levels of IRS-1 protein only when phosphorylated at Ser318. Note: Ser318 is the mouse residue; the corresponding human residue is Ser323. The antibody cross reacts with a inducible nonspecific band at around 57 kDa.

Source / Purification

Monoclonal antibody is produced by immunizing animals with a synthetic phosphopeptide corresponding to residues surrounding Ser318 of mouse IRS-1 protein.

Western Blotting

Western Blotting

Western blot analysis of extracts from serum-starved C2C12 cells, untreated or insulin-treated (150 nM for 5 min.), using Phospho-IRS-1 (Ser318) (D51C3) Rabbit mAb (upper), or IRS-1 Antibody #3407 (lower).

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).

PKC phosphorylates mouse IRS-1 at Ser318 (human Ser323) by insulin receptor activation or by other stimulation such as TPA, IL-6, retinoic acid treatment (11-14) . The phosphorylation at Ser318 acts as a negative feedback signal to down regulates of insulin effect (14-16).

  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. Greene, M.W. et al. (2004) Biochem J 378, 105-116.
  12. Weigert, C. et al. (2006) J Biol Chem 281, 7060-7067.
  13. del Rincón, S.V. et al. (2004) Oncogene 23, 9269-9279.
  14. Moeschel, K. et al. (2004) J Biol Chem 279, 25157-25163.
  15. Weigert, C. et al. (2005) J Biol Chem 280, 37393-37399.
  16. Hennige, A.M. et al. (2006) FASEB J 20, 1206-1208.

Application References

Have you published research involving the use of our products? If so we'd love to hear about it. Please let us know!

Companion Products

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

Products