Project #1. Mapping K+ channel—partner protein interactions: Some K+ channels must co-assemble with membrane-embedded b-subunits for proper physiological function. In this project, we are mapping the protein-protein interactions between the KCNQ1 K+ channel and a family of transmembrane peptides: the KCNEs. To map out these protein-protein interactions, several different techniques will be used. These include, but are not limited to, membrane protein biochemistry, chemical modification, and electrophysiology.
Project #2. Assembly and trafficking of K+ channel complexes: Efficient assembly and trafficking of K+ channel complexes is critical for physiological function. Several mutations that prevent the assembly and trafficking of the KCNQ1-KCNE1 K+ channel complex give rise to cardiac arrhythmias and congenital deafness. This rotation project involves measuring the rates of ER-exit, cell surface internalization and recycling of wild type and mutant K+ channel complexes. These rates will be measured using cell surface and pulse-chase labeling methods. Immunofluorescence will also be utilized for visualization and co-localization of K+ channel complexes in fixed and living cells.
Project #3. Synthesis of Small Molecules for probing K+ channel structure and function: Several basic structure/function questions remain with K+ channel complexes: (1) What is the stoichiometry of a functioning complex? (2) Do multiple KCNE partnering proteins assemble with one K+ channel? (3) Do sub- or super-stoichiometric complexes exist? For this rotation project, we are synthesizing novel small molecule probes and using them in combination with electrophysiology to address these and other basic structural questions about K+ channel complexes.