IRS-4 (Insulin Receptor Substrate 4)

Insulin Receptor Substrate 4 (IRS-4) is a new member of the insulin receptor substrate family. IRS-4 is a 133kD protein that undergoes rapid tyrosine phosphorylation in response to insulin. IRS-4 was originally discovered and characterized in human embryonic kidney (HEK) 293 cells where it is the predominant insulin-dependent phosphotyrosine protein. Subcellular fractionation of HEK 293 cells revealed that about 50% of IRS-4 is located in cellular membranes whereas immunofluoresence showed that IRS-4 is concentrated at the plasma membrane. \n\nApplications: \nSuitable for use in Immunoblot and Immunoprecipitation. Other applications not tested.\n\nRecommended Dilution:\nImmunoblot Analysis: 0.5-2.0ug/ml detected IRS-4 in RIPA lysates from human embryonic kidney (HEK) cells and rat L6 cells. The IRS-4 protein band appears to run at a slightly lower MWapp on minigels than is reported in literature. HEK cell lysate was resolved by electrophoresis, transferred to nitrocellulose and probed with anti-rabbit IRS-4 (1ug/ml). Proteins were visualized using a goat anti-rabbit secondary antibody conjugated to HRP and a chemiluminescence detection system.\n\nImmunoprecipitation: 4ug immunoprecipitated IRS-4 from 500ug of human embryonic kidney RIPA lysate.\n\nOptimal dilutions to be determined by the researcher.\n\nStorage and Stability:\nMay be stored at 4 degrees C for short-term only. For long-term storage and to avoid repeated freezing and thawing, add sterile glycerol (40-50%), aliquot and store at -20 degrees C or colder. Aliquots are stable for at least 12 months at -20 degrees C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.

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SPECIFICATIONS

Catalog Number

I8700-25

Size

200ug

Applications

IP, WB

Hosts

Rabbit

Reactivities

Hum, Rat

Form

Supplied as a liquid in 0.1M Tris-glycine, pH 7.4, 0.15M sodium chloride, 0.05% sodium azide before the addition of glycerol to 30%.

P Type

Pab

Purity

Purified by Protein A affinity chromatography.

Isotype

IgG

References

1. Fantin, V.R., et al., J. Biol. Chem. 273: 10,726-10,732 (1998). 2. Lavan, B.E., et al., J. Biol. Chem. 272: 21,403-21,407 (1997).

Additional Info

Recognizes IRS-4, Mr 133kD-160kD, due to multiple phosphorylation sites. Specificity for IRS-4 was demonstrated by using the immunizing peptide to inhibit antibody binding. Species Crossreactivity: Human and rat.