K+ channel protein complexes in auditory biology

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DESCRIPTION (provided by applicant): The long-term goal of this research is to elucidate the molecular and cellular mechanisms that ensure potassium channel protein-protein complexes properly assembly and maintain K+ homeostasis in the cochlear duct. The KCNQ1-KCNE1 K+ channel complex is the exclusive mechanism for endolymphatic K+ secretion into the cochlear duct. Genetic mutations in either KCNQ1 or KCNE that disrupt the assembly, trafficking or function of the complex give rise to Jervell and Lange-Nielsen Syndrome, a recessive form of congenital hearing loss accompanied with syncopal episodes. This application is directed at determining the basic mechanisms of KCNQ1-KCNE1 assembly and trafficking in the inner ear. There are three aims to this application: (1) we will identify the residues that line the protein-protein interface of the KCNQ1-KCNE1 complex utilizing a combination of biochemical and electrophysiological experiments; (2) we will determine the cellular mechanisms that ensure KCNE1 assembles with KCNQ1 by examining the cellular trafficking patterns of the proteins using enzymatic deglycosylation, membrane fractionation, cell surface labeling methods and immunofluorescence; (3) we will investigate a Jervell and Lange-Nielsen Syndrome (JLNS) mutation that disrupts assembly and trafficking of the complex via N-linked glycosylation. For this aim, we will examine the role of N-linked glycosylation in KCNE1 biogenesis, complex assembly and cellular trafficking. The results from these aims will provide a molecular and cellular framework, which will aid in the understanding of JLNS and other KCNQ1-KCNE-linked diseases.