双向信号传递是细胞间通讯领域中新近阐明的机制,酪氨酸激酶受体-配体(Eph-ephrin)介导的双向信号传递是此机制中的一个重要代表.Eph酪氨酸激酶家族受体及其配体ephrin家族成员是在神经发育、血管新生等方面起重要作用的分子,通过Eph向细胞内传递的信号称为正向信号,通过其配体ephrin的信号称为反向信号.Ephrin家族又可根据分子结构分为2个亚家族,其中ephrinB为跨膜蛋白,可通过酪氨酸磷酸化依赖和PDZ结合结构域介导2种方式向胞内传递反向信号,活化FAK、JNK、Wnt等信号通路,ephrinA为糖基磷脂酰肌醇锚定蛋白,也具有反向信号传递功能.
Bidirectional signal transduction is a newly elucidated mechanism in intercellular communication. The bidirectional signal transduction mediated by the Eph-ephrin is an important representative in this field. The Eph family receptor tyrosine kinases and their membrane-bound ligands, the ephrins, play pivotal roles in the development of nervous system, angiogenesis, etc. The signal transduction into cells by Eph receptors is the forward signal, whereas the signal transduction by ephrins is the reverse signal. Based on their molecular structures, the ephrins can be divided into two subclasses, i.e. ephrinA and ephrinB. The ephrinBs are transmembrane proteins, which can activate FAK, JNK and Wnt signal transduction pathways through phosphotyrosine-dependent signaling and PDZ-binding motif-dependent signaling. The ephrinAs are glycosylphosphotidylinositol (GPI) anchored proteins, which can also mediate reverse signal transduction.