IRS1 (Insulin Receptor Substrate 1) is a crucial signalling protein that mediates the body’s response to insulin and growth factors. Serving as an adaptor, IRS1 links activated insulin receptors to various downstream pathways, regulating processes such as glucose uptake, glycogen synthesis, protein production, and cell growth. Dysregulation of IRS1 is associated with insulin resistance, type 2 diabetes, and may also contribute to cancer and cardiovascular diseases.