|
The transforming growth factor beta (TGF-β) superfamily is a large family of structurally related cell regulatory proteins that was named after its first member, TGF-β1, originally described in 1983. Many proteins have since been described as members of the TGF-β superfamily in a variety of species, including invertebrates as well as vertebrates and categorized into 23 distinct gene types that fall into four major subfamilies: * the decapentaplegic-Vg-related (DVR) related subfamily (including the bone morphogenetic proteins and the growth differentiation factors) * the activin/inhibin subfamily * the TGF-β subfamily * a group encompassing various divergent members Transforming growth factor-beta (TGF-beta) is a multifunctional peptide that controls proliferation, differentiation and other functions in many cell types. TGF-beta-1 is a peptide of 112 amino acid residues derived by proteolytic cleavage from the C-terminal of a precursor protein. These proteins interact with a conserved family of cell surface serine/threonine-specific protein kinase receptors, and generate intracellular signals using a conserved family of proteins called SMADs. They play fundamental roles in the regulation of basic biological processes such as growth, development, tissue homeostasis and regulation of the immune system.〔 ==Structure== Proteins from the TGF-beta family are only active as homo- or heterodimer; the two chains being linked by a single disulfide bond. From X-ray studies of TGF-beta-2, it is known that all the other cysteines are involved in intrachain disulfide bonds. As shown in the following schematic representation, there are four disulfide bonds in the TGF-beta's and in inhibin beta chains, while the other members of this family lack the first bond. interchain | +------------------------------------------|+ | || | | | | | | +------+ +--|----------------------------------------+ | +------------------------------------------+ where 'C' denotes a conserved cysteine involved in a disulfide bond. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Transforming growth factor beta superfamily」の詳細全文を読む スポンサード リンク
|