Figure 1.

The IGF system and its components. The IGF family comprises several receptors, including transmembrane tyrosine kinase-linked receptors (RTKs)—Insulin-like growth factor receptor 1 (IGF-1R), Insulin-like growth factor receptor 2 (IGF-2R), Insulin receptor (IR) A and B, and their hybrids; three structurally and functionally similar ligands—IGF-1, IGF-2, and Insulin; and six soluble binding proteins: Insulin-like growth factor binding proteins (IGFBPs) 1–6. Depending on the target tissue, the levels of the binding proteins are regulated by IGFBP proteases (not shown). Receptor ligand interaction leads to downstream signaling through PI3K-AKT and RAS-RAF-MAPK, which regulates proliferation, survival, metastasis, and metabolism. Created with BioRender.com.