INSULIN-LIKE GROWTH FACTOR-BINDING PROTEIN PROTEOLYSIS - AN EMERGING PARADIGM IN INSULIN-LIKE-GROWTH-FACTOR PHYSIOLOGY

In biologic fluids, insulinlike growth factors (IGF-I and IGF-II) ave bound to high-affinity insulinlike growth factor binding proteins (IGF BPs), of which seven have now been identified (IGFBPs 1-7). In a varie ty of biologic fluids, several IGFBPs undergo proteolytic degradation. Such degradation can lead to increased IGF bioavailability at the cel l surface, facilitating receptor interactions. Herein, recent data ide ntifying several IGFBP-degrading proteinases and their effects on IGF bioactivity is reviewed, and how IGFBP proteolysis is regulated by IGF s and IGFBPs, as well as how IGFBP cleavage analysis provides insights into the structure and function of IGFBPs, is explored. (C) 1997, Els evier Science Inc.