Egea Joaquim, Klein Rüdiger
Max-Planck Institute of Neurobiology, D-82152 Martinsried, Germany.
Trends Cell Biol. 2007 May;17(5):230-8. doi: 10.1016/j.tcb.2007.03.004. Epub 2007 Apr 8.
Ephrins are cell-surface tethered guidance cues that bind to Eph receptor tyrosine kinases in trans on opposing cells. In the developing nervous system, the Eph-ephrin signaling system controls a large variety of cellular responses including contact-mediated attraction or repulsion, adhesion or de-adhesion, and migration. Eph-ephrin signaling can be bidirectional, and is subject to modulation by ectodomain cleavage of ephrins and by Eph-ephrin endocytosis. Recent work has highlighted the importance of higher-order clustering of functional Eph-ephrin complexes and the requirement for Rho GTPases as signal transducers. Co-expression of Ephs and ephrins within the same cellular membrane can result in Eph-ephrin cis interaction or in lateral segregation into distinct domains from where they signal opposing effects on the axon.
Ephrin是细胞表面锚定的导向信号分子，可与相对细胞上的Eph受体酪氨酸激酶进行反式结合。在发育中的神经系统中，Eph-ephrin信号系统控制着多种细胞反应，包括接触介导的吸引或排斥、黏附或去黏附以及迁移。Eph-ephrin信号可以是双向的，并且受ephrin胞外域裂解和Eph-ephrin内吞作用的调节。最近的研究突出了功能性Eph-ephrin复合物高阶聚集的重要性以及Rho GTPases作为信号转导分子的必要性。Ephs和ephrins在同一细胞膜内的共表达可导致Eph-ephrin顺式相互作用，或横向分离成不同的结构域，从这些结构域它们对轴突发出相反的作用信号。
