IGF1R is a receptor tyrosine kinase that mediates the actions of insulin-like growth factor 1 (IGF1). It binds IGF1 with high affinity and IGF2 and insulin (INS) with a lower affinity. The activated IGF1R is involved in cell growth and survival control. IGF1R is crucial for tumor transformation and survival of malignant cels. Ligand binding activates the receptor kinase, leading to receptor autophosphorylation and phosphorylation of multiple signaling adapter proteins . Phosphorylation of IRS proteins can lead to the activation of two main signaling pathways, the PI3K-AKT/PKB pathway and the Ras-MAPK pathway, activation of which in turn increases cellular proliferation, inhibits apoptosis and stimulates protein synthesis. References: The UniProt Consortium. Nucleic Acids Res. 47: D506-515 (2019); Nucleic Acids Res. 2016 Jan 4;44(D1):D733-45, PMID:26553804