Seven IGFBPs has been described to modulate the IGF activity. IGFBPs transport IGFs, in this way they may inhibit mitogenesis, differentiation, survival, and other IGF-stimulated events. IGFBPs structurally are characterized by three domains: the amino-terminal, the carboxyl-terminal, and an intermediate variable L-domain. Members of the IGFBP family exhibit 67–70% structural homology. The greatest homology among the IGFBPs is in the N- and C-terminal regions. Some IGFBPs bind to the extracellular matrix (IGFBP-2, -3, -5, and -6). In fact, a heparin-binding domain (HBD) has been identified in the C-terminal region of these binding proteins. IGFBP-6 decreases cancer cell proliferation and survival by inhibiting the effects of IGF-II. IGFBP-6 has binding preference for IGF-II over IGF-I. In addition to IGF regulation, IGFBP-6 has IGF-independent effects, which include the inhibition of angiogenesis and promotion of rhabdomyosarcoma (RMS) cell migration. Prohibitin-2, a single-span membrane protein, is a key regulator of IGFBP-6-induced RMS cell motility. Recombinant IGFBP-6 can be internalized and translocated to the nucleus, where it interacts with the vitamin D receptor and thyroid hormone receptor alpha 1 (TR). Consequently, IGFBP-6 inhibits osteoblastic differentiation that is mediated by vitamin D3 and regulated by TR in the presence of Triiodothyronine.
Size
25 μg
Concentration
n/a
Applications
BA
Other Names
Insulin-like growth factor binding protein 6 (IBP6), IGFBP6