Kir6.2, an inward rectifying ATP-sensitive K+ (KATP) channel, is an integral plasma membrane protein that transduces metabolic events into membrane potential changes within the cell. In pancreatic Beta-cells, KATP channels play a key role in glucose-induced insulin secretion. Moreover, KATP channels have roles in hormone secretion, nueurtotransmitter release, as well as cardioprotection during ischemic stress. Recently, Kir6.2 and the sulfonylurea receptor, SUR1, were found expressed in pancreatic Beta-cells, and reconstitute a functional KATP channel. However, the specific protein domains of Kir6.2 and SUR1 necessary for association, or the way local ATP levels are regulated in the channel microenvironment are unknown. The yeast two-hybrid system together with deletion mutant analysis will be used to determine the domains necessary for this association, as well as any possible interaction with regulatory proteins, such as adenylate kinase. Furthermore, electrophysiology, e.g., patch clamp, techniques will be used on COS cells transfected with various Kir6.2 and SUR1 mutated proteins to ascertain the physiological significance of such interactions. Therefore, this research project will focus on two aspects of Kir6.2: 1) characterizing specific domains necessary for its interaction with SUR1, and 2) determining the regulation of this interaction, as well as the overall regulation of this KATP channel. Thus, project increases the knowledge of basic and essential physiological processes, such as, insulin secretion and cardio- protection.
| Carrasco, A J; Dzeja, P P; Alekseev, A E et al. (2001) Adenylate kinase phosphotransfer communicates cellular energetic signals to ATP-sensitive potassium channels. Proc Natl Acad Sci U S A 98:7623-8 |
