Direct interaction of receptor tyrosine kinases, EphA4 and PDGFRβ, plays an important role in the proliferation of neural stem cells

Receptor tyrosine kinases mediate the extracellular signals and transmit them into the cytoplasm by activating intracellular proteins through tyrosine phosphorylation. Both Ephs and platelet-derived growth factor (PDGF) receptors (PDGFRs) have been implicated in neurogenesis, but the functional interaction between these two pathways is poorly understood. Here, we demonstrated that EphA4 directly interacts with PDGFRβ and mutually activates each other when expressed in HEK293T cells. H9-derived neural stem cells express Ephs and PDGFRs, and their proliferation is stimulated by ephrin-A1 and PDGF-BB with further augmentation by their combined application. As both EphA4 and PDGFRβ play important roles in preventing neurodegeneration and promoting neuroprotection, their interaction and transactivation might transduce the signal through the EphA4/PDGFRβ complex and augment the proliferation of neural stem cells.