Abstract

Introduction

Materials & Methods

Results

Discussion & Conclusion

References

Discussion
Board

A role for receptor tyrosine kinase activation in modulating vascular reactivity has been increasingly appreciated. In general, the net effect of receptor tyrosine kinase signaling on vascular function has been demonstrated to be primarily vasodilator. We have suggested that a component of this effect may relate to tyrosine kinase-mediated regulation of G-protein coupled receptor-mediated vasodilation. We have demonstrated that insulin (a prototypical polypeptide growth factor which activates its receptor tyrosine kinase) enhances G-protein coupled-mediated vasodilation; further, this effect is related to sensitization of adenylyl cyclase. However, the cellular mechanisms responsible for this enhancement remain unclear. Therefore, to examine the mechanism of tyrosine kinase-mediated regulation of adenylyl cyclase, we assessed the effects of the insulinomimetic vanadate (a tyrosine phosphatase inhibitor) on adenylyl cyclase activity in Flag epitope-tagged adenylyl cyclase isoform VI (FAC6) transiently transfected into human embryonic kidney cells (HEK 293 cells). Data to be presented demonstrates that vanadate enhances activation of adenylyl cyclase isoform VI in a tyrosine kinase-dependent manner. Further, enhanced activity is related to a novel tyrosine kinase-dependent enhanced serine phosphorylation of the enzyme.

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