BMP-4 forms homodimers or heterodimers with BMP-2 and signals through receptor complexes composed of type I (primarily ActRIA or BMPR-IA) and type II (primarily ActRIIA or BMPR-II) receptors. BMP-4 plays an important role in mesenchyme formation, epidermal determination, suppression of neural induction, the development of multiple organs, and tissue repair. Compared to BMP-4 homodimers, BMP-4/BMP-7 heterodimers exhibit a greater potency in inducing osteogenic differentiation. The bioavailability of BMP-4 is regulated by its interaction with multiple proteins and glycosaminoglycans.
