Central role of calcium-dependent tyrosine kinase PYK2 in endothelial nitric oxide synthase-mediated angiogenic response and vascular function

Background-The involvement of Ca2+-dependent tyrosine kinase PYK2 in the Akt/endothelial NO synthase pathway remains to be determined. Methods and Results-Blood flow recovery and neovessel formation after hind-limb ischemia were impaired in PYK2(-/-) mice with reduced mobilization of endothelial progenitors. Vascular endothelial growth factor (VEGF)-mediated cytoplasmic Ca2+ mobilization and Ca2+- independent Akt activation were markedly decreased in the PYK2-deficient aortic endothelial cells, whereas the Ca2+- independent AMP-activated protein kinase/protein kinase-A pathway that phosphorylates endothelial NO synthase was not impaired. Acetylcholine-mediated aortic vasorelaxation and cGMP production were significantly decreased. Vascular endothelial growth factor-dependent migration, tube formation, and actin cytoskeletal reorganization associated with Rac1 activation were inhibited in PYK2-deficient endothelial cells. PI3-kinase is associated with vascular endothelial growth factor-induced PYK2/Src complex, and inhibition of Src blocked Akt activation. The vascular endothelial growth factor-mediated Src association with PLC gamma 1 and phosphorylation of (783)Tyr-PLC gamma 1 also were abolished by PYK2 deficiency. Conclusion-These findings demonstrate that PYK2 is closely involved in receptor- or ischemia-activated signaling events via Src/PLC gamma 1 and Src/PI3- kinase/Akt pathways, leading to endothelial NO synthase phosphorylation, and thus modulates endothelial NO synthase-mediated vasoactive function and angiogenic response.