Insulin receptor substrate 1 and related adaptor proteins (IRS proteins)

Insulin receptor substrate (IRS) proteins, including IRS-1, IRS-2, IRS-3, and IRS-4, are essential adaptor molecules that link the activation of insulin and insulin-like growth factor 1 (IGF-1) receptors to downstream intracellular signaling cascades. Upon receptor activation, IRS proteins undergo tyrosine phosphorylation, creating docking sites for SH2-domain-containing proteins such as phosphoinositide 3-kinase (PI3K) and Grb2, which subsequently regulate glucose uptake, lipid metabolism, and gene expression (UniProt P35568). IRS-1 is primarily associated with metabolic regulation in muscle and adipose tissue, while IRS-2 plays a significant role in liver metabolism and pancreatic beta-cell function (PubMed: 11893336). Dysregulation of these proteins, often through excessive serine phosphorylation or accelerated degradation, is a central mechanism in the development of insulin resistance and type 2 diabetes (PubMed: 11595754). In oncology, IRS-1 and IRS-2 are frequently overexpressed or hyperactivated, contributing to the progression of breast, prostate, and colorectal cancers by promoting cell survival and proliferation (PubMed: 21832056). Therapeutic interventions include small molecules like NT157 that induce IRS degradation to treat cancer, as well as insulin sensitizers that aim to enhance IRS function in metabolic disorders (PubMed: 22964583).

Other names

IRS-1IRS-2IRS-3IRS-4Insulin receptor substrate familyIRS adaptor proteins

Drugs targeting IRS proteins typically act by inhibiting their recruitment to receptors, promoting their degradation, or modulating their phosphorylation state to either restore insulin sensitivity or block oncogenic signaling pathways like PI3K/Akt.