Cell Signaling Technology

Product Pathways - PathScan ELISA

PathScan® Phospho-IRS-1 (Ser302) Sandwich ELISA Kit #7283

When ordering five or more kits, please contact us for processing time and pricing at sales@cellsignal.com.

Important Ordering Details: Product is assembled upon order to ensure maximum activity. Domestic: Please allow up to two weeks for your order to be processed and shipped. International: Please allow up to three weeks, depending on the country, for your order to be processed and shipped.

Kit Includes Volume Solution Color
IRS-1 Ab Coated Microwells 96 tests
P-IRS-1 (S302) Detection Ab 11 ml Green
Anti-rabbit IgG, HRP-linked Antibody 11 ml Red
TMB Substrate #7004 11 ml Colorless
STOP Solution #7002 11 ml Colorless
Sealing Tape 2 sheets
ELISA Wash Buffer (20X) 25 ml Colorless
Sample Diluent 25 ml Blue
Cell Lysis Buffer (10X) #9803 15 ml Yellowish

Note: 12 8-well modules –Each module is designed to break apart for 8 tests.
Note: Kit should be stored at 4°C with the exception of Cell Lysis Buffer, which is stored at –20°C (packaged separately).

Species Cross-Reactivity

H

Reactivity Key:  H=Human
Species enclosed in parentheses are predicted to react based on 100% sequence homology.

Description

The PathScan® Phospho-IRS-1 (Ser302) Sandwich ELISA Kit is a solid phase sandwich enzyme-linked immunosorbent assay (ELISA) that detects endogenous levels of IRS-1 when phosphorylated at Ser302. An IRS-1 Mouse Antibody* has been coated onto the microwells. After incubation with cell lysates, IRS-1 (phospho and nonphospho) is captured by the coated antibody. Following extensive washing, a Phospho-IRS-1 (Ser302) Rabbit Detection Antibody* is added to detect phosphorylation of Ser302 on the captured IRS-1 protein. Anti-rabbit IgG, HRP-linked Antibody #7074* is then used to recognize the bound detection antibody. HRP substrate, TMB, is added to develop color. The magnitude of the absorbance for this developed color is proportional to the quantity of IRS-1 phosphorylated at Ser302.* Antibodies in kit are custom formulations specific to kit.

Specificity / Sensitivity

CST's PathScan® Phospho-IRS-1 (Ser302) Sandwich ELISA Kit #7283 detects endogenous levels of IRS-1 when phosphorylated at Ser302. As shown in Figure 1, a significant induction of IRS-1 phosphorylation at Ser302 can be detected in hSkMC cells following treatment with insulin using the Phospho-IRS-1 (Ser302) Sandwich ELISA Kit #7283. The level of total IRS-1 (phospho and nonphospho) remains unchanged as shown by Western analysis and by PathScan® Total IRS-1 Sandwich ELISA Kit #7328 (Figure 1). This kit detects proteins from the indicated species, as determined through in-house testing, but may also detect homologous proteins from other species.

ELISA - Western correlation

ELISA - Western correlation

Figure 1. Treatment of hSkMC cells with insulin stimulates phosphorylation of IRS-1 at Ser302, detected by the PathScan® Phospho-IRS-1 (Ser302) Sandwich ELISA Kit #7283, but does not affect the level of total IRS-1 detected by PathScan® Total IRS-1 Sandwich ELISA Kit #7328. hSkMC cells (80-90% confluent) were starved overnight and treated with 100 nM insulin for 15 minutes at 37oC. The absorbance readings at 450 nm are shown in the top figure, while the corresponding Western blots using IRS-1 (L3D12) Mouse mAb #3194 (left panel) or Phospho-IRS-1 (Ser302) (34C7) Rabbit mAb #2491 (right panel) are shown in the bottom figure.

Sensitivity

Sensitivity

Figure 2. The relationship between the protein concentration of the lysate from untreated and insulin-treated hSkMC cells and the absorbance at 450 nm is shown.

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).

  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.

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Rabbit Monoclonals are produced under license (granting certain rights, including those under U.S. Patent No. 5,675,063) from Epitomics, Inc.

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

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