IGF-binding proteins prolong the half-life of the IGFs and have been shown to either inhibit or stimulate the growth promoting effects of the IGFs on cell culture. They alter the interaction of IGFs with their cell surface receptors. Also exhibits IGF-independent antiproliferative and apoptotic effects mediated by its receptor TMEM219/IGFBP-3R. Inhibits the positive effect of humanin on insulin sensitivity (PubMed:19623253). Promotes testicular germ cell apoptosis (PubMed:19952275).
