Brückner K, Pasquale E B, Klein R
European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany. USA.
Science. 1997 Mar 14;275(5306):1640-3. doi: 10.1126/science.275.5306.1640.
Axonal pathfinding in the nervous system is mediated in part by cell-to-cell signaling events involving members of the Eph receptor tyrosine kinase (RTK) family and their membrane-bound ligands. Genetic evidence suggests that transmembrane ligands may transduce signals in the developing embryo. The cytoplasmic domain of the transmembrane ligand Lerk2 became phosphorylated on tyrosine residues after contact with the Nuk/Cek5 receptor ectodomain, which suggests that Lerk2 has receptorlike intrinsic signaling potential. Moreover, Lerk2 is an in vivo substrate for the platelet-derived growth factor receptor, which suggests crosstalk between Lerk2 signaling and signaling cascades activated by tyrosine kinases. It is proposed that transmembrane ligands of Eph receptors act not only as conventional RTK ligands but also as receptorlike signaling molecules.
神经系统中的轴突导向部分是由涉及Eph受体酪氨酸激酶（RTK）家族成员及其膜结合配体的细胞间信号传导事件介导的。遗传学证据表明跨膜配体可能在发育中的胚胎中传导信号。跨膜配体Lerk2的胞质结构域在与Nuk/Cek5受体胞外结构域接触后，其酪氨酸残基发生磷酸化，这表明Lerk2具有类似受体的内在信号传导潜力。此外, Lerk2是血小板衍生生长因子受体的体内底物，这表明Lerk2信号传导与酪氨酸激酶激活的信号级联之间存在串扰。有人提出，Eph受体的跨膜配体不仅作为传统的RTK配体起作用，而且还作为类似受体的信号分子起作用。
