Insulin-like Growth Factors

The insulin-like growth factor (IGF) family consists of two ligands (IGF-I and IGF-II), two cell-surface receptors (IGF-IR and IGF-IIR), at least six high-affinity binding proteins (IGFBPs 1–6), and a group of low-affinity IGFBP-related proteins (IGFBP-rPs). Members of the IGF family form a network of interactions both among themselves and with other growth factor families and their signaling pathways. IGFs play important roles in regulating cell proliferation, differentiation, apoptosis, and transformation.