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Transforming growth factor alpha (TGF-α) is a protein that in humans is encoded by the TGFA gene.〔 As a member of the epidermal growth factor (EGF) family, TGF-α is a mitogenic polypeptide.〔Ojeda, S.; Ma, Y.; Rage, F. The transforming growth factor alpha gene family is involved in the neuroendocrine control of mammalian puberty. ''Mol. Psychiatry'' 1997, 2, 355.〕 The protein becomes activated when binding to receptors capable of protein kinase activity for cellular signaling. TGF-α is a transforming growth factor that is a ligand for the epidermal growth factor receptor, which activates a signaling pathway for cell proliferation, differentiation and development. This protein may act as either a transmembrane-bound ligand or a soluble ligand. This gene has been associated with many types of cancers, and it may also be involved in some cases of cleft lip/palate. ==Synthesis== TGF-α is synthesized internally as part of a 160 (human) or 159 (rat) amino acid transmembrane precursor.〔Ferrer, I.; Alcantara, S.; Ballabriga, J.; Olive, M.; Blanco, R.; Rivera, R.; Carmona, M.; Berruezo, M.; Pitarch, S.; Planas, A. Transforming growth factor- α (TGF-α) and epidermal growth factor-receptor (EGF-R) immunoreactivity in normal and pathologic brain. Prog. Neurobiol. 1996, 49, 99.〕 The precursor is composed of an extracellular domain containing a hydrophobic transmembrane domain, 50 amino acids of TGF-α, and a 35-residue-long cytoplasmic domain.〔 In its smallest form TGF-α has six cysteines linked together via three disulfide bridges. Collectively all members of the EGF/TGF-α family share this structure. The protein, however, is not directly related to TGF-β. In the stomach, TGF-α is manufactured within the normal gastric mucosa.〔Coffey, R.; Gangarosa, L.; Damstrup, L.; Dempsey, P. Basic actions of transforming growth factor- α and related peptides. Eur. J. Gastroen. Hepat. 1995, 7, 923.〕 TGF-α has been shown to inhibit gastric acid secretion.〔 Limited success has resulted from attempts to synthesize of a reductant molecule to TGF-α that displays a similar biological profile. 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「TGF alpha」の詳細全文を読む スポンサード リンク
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