Rabbit Anti-Human IRS1 (phospho Ser312) monoclonal antibody for WB. Insulin receptor substrates (IRS) are responsible for several insulin related activities, such as glucose homeostasis, cell growth, cell transformation, apoptosis and insulin signal transduction. Serine/threonine phosphorylation of IRS-1 has been demonstrated to be a negative regulator of insulin signaling and is responsible for its degradation, although IRS-1 degradation pathways are not well understood. IRS-1 has also been shown to be constitutively activated in cancers such as breast cancer, Wilm and quote;s tumors, and adrenal cortical carcinomas, thus making IRS-1 phosphorylation and subsequent degradation an attractive therapeutic option. To date there have been four subtypes identified: IRS-1,2,3, and 4, with IRS-1 being widely expressed.