Protein kinase C-dependent protein kinase D activation modulates ERK signal pathway and endothelial cell proliferation by vascular endothelial growth factor.
Vascular endothelial growth factor (VEGF) is essential for many angiogenic processes both in normal conditions and in pathological conditions. However, the signaling pathways involved in VEGF-induced angiogenesis are not well defined. Protein kinase D (PKD), a newly described serine/threonine protein kinase, has been implicated in many signal transduction pathways and in cell proliferation. We hypothesized that PKD would mediate VEGF signaling and function in endothelial cells. Here we found that VEGF rapidly and strongly stimulated PKD phosphorylation and activation in endothelial cells via VEGF receptor 2 (VEGFR2). The pharmacological inhibitors for phospholipase Cgamma (PLCgamma) and protein kinase C (PKC) significantly inhibited VEGF-induced PKD activation, suggesting the involvement of the PLCgamma/PKC pathway. In particular, PKCalpha was critical for VEGF-induced PKD activation since both overexpression of adenovirus PKCalpha dominant negative mutant and reduction of PKCalpha expression by small interfering RNA markedly inhibited VEGF-induced PKD activation. Importantly, we found that small interfering RNA knockdown of PKD and PKCalpha expression significantly attenuated ERK activation and DNA synthesis in endothelial cells by VEGF. Taken together, our results demonstrated for the first time that VEGF activates PKD via the VEGFR2/PLCgamma/PKCalpha pathway and revealed a critical role of PKD in VEGF-induced ERK signaling and endothelial cell proliferation.
Wong
Chelsea
C
Cardiovascular Research Institute and Department of Medicine, University of Rochester Medical Center, Rochester, New York 14642, USA.
Jin
Zheng-Gen
ZG
D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D001011:Aorta / Q000166:cytology; D015153:Blotting, Western; D002417:Cattle; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects*; D004247:DNA / Q000096:biosynthesis; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D004789:Enzyme Activation; D006801:Humans; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D007700:Kinetics; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009154:Mutation; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000494:pharmacology; D015398:Signal Transduction; D013936:Thymidine / Q000378:metabolism; D014471:Umbilical Veins / Q000166:cytology; D042461:Vascular Endothelial Growth Factor A / Q000494:pharmacology*; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000378:metabolism
D007527:Isoenzymes; D034741:RNA, Small Interfering; D042461:Vascular Endothelial Growth Factor A; D004247:DNA; C089212:protein kinase D; D040301:Vascular Endothelial Growth Factor Receptor-2; D011493:Protein Kinase C; D020928:Mitogen-Activated Protein Kinases; D013936:Thymidine