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转化生长因子 β(TGF β)超家族成员是一类多功能的细胞调节蛋白 ,它们在多细胞动物的发育和体内功能平衡方面发挥关键作用。它们与I,II型丝氨酸 /苏氨酸激酶受体结合后 ,再与下游效应分子 Smad蛋白结合 ,进而介导从胞膜到胞核的多种效应。受体调节Smads的蛋白质分子 ,被激活的I型受体磷酸化后与Smad4形成异源复合物 ,然后转位于核内以调控基因转录。在低剂量时 ,TGF β可抑制淋巴细胞激活 ,因此具有免疫抑制作用。在高浓度时 ,TGF β能促进创伤愈合和导致纤维化
Members of the Transforming Growth Factor β (TGFβ) superfamily are multifunctional, family of cell-regulatory proteins that play key roles in the development of multicellular animals and in homeostasis. After they bind to type I and type II serine / threonine kinase receptors, they bind to the downstream effector Smad protein, which in turn mediates multiple effects from the cell membrane to the nucleus. The receptor regulates the protein molecules of Smads. The activated type I receptor phosphorylates and forms a heterologous complex with Smad4, then translocates in the nucleus to regulate gene transcription. At low doses, TGFβ inhibits lymphocyte activation and therefore has immunosuppressive effects. At high concentrations, TGFβ promotes wound healing and leads to fibrosis