Smads基因功能的研究进展

Progress in the Function of Smad Genes

转化生长因子 -β( TGF-β)超家族通过调节细胞的增殖、分化、移行和凋亡而在脊椎动物发育过程中起重要的作用 . SMAD家族是一类新发现的 TGF-β信号的细胞质内介导者 ,它们可将TGF- β信号直接从细胞膜转导入细胞核内 .受体激活的 SMADs被特导性的细胞表面受体磷酸化后 ,与通用介导分子 SMAD4相互作用形成异源三聚体 ,转移至细胞核内并激活靶基因的转录 .抑制型 SMADs通过负反馈途径阻断或减弱 TGF- β信号 .SMADs通过与 TGF- β配体应答的启动子序列及其它转录因子和辅助活化因子相互作用而调节转录 .通过同源重组在小鼠中定位敲除Smads基因的研究已经开始揭示 SMADs分子在脊椎动物发育过程中的功能 .

Transforming growth factor β(TGF β) superfamily plays important roles during vertebrate development by regulating cell proliferation,differentiation,migration and apoptosis.SMAD family is a new family of intracellular mediators that transduce TGF β signals directly from the cell membrane to the nucleus.Receptor activated SMADs are phosphorylated by specific cell surface receptors,and then form heterotrimer with a common mediator SMAD4 and translocate into nucleus where they activate the transcription of the target genes.Inhibitory SMADs function in a negative feedback loop to block or reduce the strength of the signals.SMADs regulate transcription through interactions of SMAD complex with ligand responsive promoter sequences and with other transcription factors and coactivators.Analysis of Smad genes by gene targeting is beginning to provide insights into SMAD function during vertebrate development.