Vav Family Proteins Couple to Diverse Cell Surface Receptors

摘要: Vav proteins are guanine nucleotide exchange factors for Rho family GTPases which activate pathways leading to actin cytoskeletal rearrangements and transcriptional alterations. contain several protein binding domains can link cell surface receptors downstream signaling proteins. Vav1 is expressed exclusively in hematopoietic cells tyrosine phosphorylated response activation of multiple receptors. However, it not known whether the recently identified isoforms Vav2 Vav3, broadly expressed, couple with similar classes receptors, nor all possess identical functional activities. We Vav1, Vav2, Vav3 at equivalent levels directly compare responses receptor activation. Although each isoform was upon representative kinases, integrin, lymphocyte antigen we found unique aspects coupling pathway. Each coprecipitated activated epidermal growth factor platelet-derived (PDGF) residues on PDGF were able mediate phosphorylation. Integrin-induced phosphorylation detected nonhematopoietic unless kinase Syk also suggesting that integrin may be restricted types express particular kinases. In addition, but or efficiently cooperate T-cell enhance NFAT-dependent transcription, while NFκB-dependent transcription. Thus, although respond there isoform-specific differences their pathways.