Insulin receptor (IR) (IR)

The insulin receptor (IR) is a transmembrane receptor tyrosine kinase that plays a central role in regulating glucose homeostasis and cellular metabolism. It exists as two main isoforms, IR-A and IR-B, which result from alternative splicing of the INSR gene; IR-A lacks exon 11 and is predominantly expressed during fetal development and in cancer cells, while IR-B includes exon 11 and is the primary isoform in adult metabolic tissues like the liver, muscle, and adipose tissue (UniProt P06213). Upon binding insulin or insulin-like growth factors, the receptor undergoes autophosphorylation, activating downstream pathways such as the PI3K/AKT pathway for metabolic control and the MAPK pathway for cell growth (NCBI Gene ID 3643). Dysregulation of IR signaling is a hallmark of type 2 diabetes and various insulin resistance syndromes, and its overexpression, particularly the IR-A isoform, is implicated in the progression of several cancers (Belfiore et al., 2009). Therapeutic strategies primarily involve insulin analogs that act as agonists to restore glucose control, though challenges such as hypoglycemia and potential mitogenic risks remain significant considerations (StatPearls, 2023). Additionally, the differential signaling of IR-A and IR-B provides a basis for developing isoform-specific modulators to treat metabolic and oncogenic diseases more precisely.

Other names

INSRCD220Insulin receptor subunit alphaInsulin receptor subunit betaInsulin receptor isoform AInsulin receptor isoform BProtein tyrosine kinase receptor

Agonist binding to the extracellular alpha subunits triggers conformational changes leading to autophosphorylation of the intracellular beta subunits' tyrosine kinase domains, initiating downstream signaling cascades such as PI3K/AKT and MAPK (StatPearls, 2023; UniProt P06213).