Paralkar V M, Weeks B S, Yu Y M, Kleinman H K, Reddi A H
Bone Cell Biology Section, National Institute of Dental Research, National Institutes of Health, Bethesda, Maryland 20892.
J Cell Biol. 1992 Dec;119(6):1721-8. doi: 10.1083/jcb.119.6.1721.
Bone morphogenetic protein 2B (BMP 2B, also known as BMP 4) induces cartilage and bone morphogenesis in ectopic extraskeletal sites. BMP 2B is one of several bone morphogenetic proteins which along with activins and inhibins are members of the transforming growth factor-beta (TGF-beta) family. Both BMP 2B and activin A, but not TGF-beta 1, induce rat pheochromocytoma PC12 neuronal cell differentiation and expression of VGF, a nervous system-specific mRNA. PC12 cells exhibited approximately 2,500 receptors per cell for BMP 2B with an apparent dissociation constant of 19 pM. Extracellular matrix components, including fibronectin, laminin, and collagen type IV potentiated the activity of BMP and activin A, with the latter being the most active. Direct experiments demonstrated that radioiodinated BMP 2B bound to collagen type IV better than to either laminin or fibronectin. These data demonstrate a common neurotrophic activity of both BMP 2B and activin A, and suggest that these regulatory molecules alone and in conjunction with extracellular matrix components may play a role in both the development and repair of nervous tissue.
骨形态发生蛋白2B（BMP 2B，也称为BMP 4）可在异位骨骼外部位诱导软骨和骨形态发生。BMP 2B是几种骨形态发生蛋白之一，它与激活素和抑制素一起，都是转化生长因子-β（TGF-β）家族的成员。BMP 2B和激活素A均可诱导大鼠嗜铬细胞瘤PC12神经元细胞分化并表达VGF（一种神经系统特异性mRNA），而TGF-β1则无此作用。PC12细胞每个细胞约有2500个BMP 2B受体，其表观解离常数为19 pM。包括纤连蛋白、层粘连蛋白和IV型胶原在内的细胞外基质成分可增强BMP和激活素A的活性，其中激活素A活性最强。直接实验表明，放射性碘化的BMP 2B与IV型胶原的结合优于与层粘连蛋白或纤连蛋白的结合。这些数据证明了BMP 2B和激活素A具有共同的神经营养活性，并表明这些调节分子单独或与细胞外基质成分共同作用，可能在神经组织的发育和修复中发挥作用。
