Saturday, June 20, 2009
Mark Shapiro, Ph.D. receives a National Institutes of Health (NIH) - American Recovery and Reinvestment Act (ARRA) award for his project "Mechanism and functional role of AKAP79/150 in M current control and excitability."
A-kinase anchoring proteins (AKAPs) organize numerous intracellular signaling pathways by bringing together their molecular components into discrete sub-cellular microdomains. One such AKAP, AKAP79/150 interacts with protein kinase A, protein kinase C (PKC), calmodulin (CaM), calcineurin, and phosphatidylinositol 4,5-bisphosphate (PIP2), along with effectors such as M-type (KCNQ, Kv7) K+ channels and certain G protein-coupled receptors. In this project, we will study which KCNQ1-5 subunits are targets of AKAP79/150, and which Gq/11-coupled receptors of sympathetic ganglia neurons (muscarinic M1, bradykinin B2, angiotensin AT1 and purinergic P2Y) use AKAP79/150 to modulate M-type channels. We will also investigate the interactions between the CaM and PIP2 molecules with AKAP79/150 that are critical to the function of both M channels and AKAP79/150. We will use a heterologous expression system in which M-channels, receptors and signaling molecules are expressed in Chinese hamster ovary (CHO) cells and preparations of rat and mouse superior cervical ganglia (SCG) neurons. Techniques to be used include fluorescence resonance energy transfer (FRET), total internal reflection fluorescence (TIRF), confocal microscopy and patch-clamp electrophysiology. We aspire to discover the mechanisms endowing AKAP79/150 in specificity towards receptors and M-type K+ channels, and its functional role in regulation of neuronal M currents.