Insulin-like growth factor-binding protein 3 (IGFBP3) is a protein with an IGFBP domain and a thyroglobulin type-I domain. The protein forms a ternary complex with insulin-like growth factor acid-labile subunit (IGFALS) and either insulin-like growth factor (IGF) I or II. In this form, it circulates in the plasma, prolonging the half-life of IGFs and altering their interaction with cell surface receptors. Diseases associated with IGFBP3 include Insulin-Like Growth Factor I and Laron Syndrome.
