SELF-FUNDING MSc BY RESEARCH PROJECT: Determination of pathogenicity of pore mutations in potassium channels linked to Long QT Syndrome

The correct function of the heart depends on an orderly sequence of electrical excitation with each heart-beat. In turn this depends on the coordinated activity of multiple ion channel proteins and electrogenic transporters. Mutations to the underlying genes lead to electrocardiogram (ECG) abnormalities and malignant, potentially fatal ventricular arrhythmias. Two genes, which encode potassium ion channels, that have been strongly linked to malignant ventricular arrhythmias are KCNQ1 and KCNH2, mutations to which can cause repolarization disorders and sudden death [1-3]. Loss-of-function mutations to these genes lead to the LQT1 and LQT2 forms of long QT syndrome (LQTS). Whilst many variants in KCNQ1 and KCNH2 have been associated with LQTS, only a relatively small fraction of these has undergone functional characterization. The objective of this project is to elucidate the effects of mutations close to the ion selectivity filter in the pore of KCNQ1 and hERG (KCNH2-encoded) channels. For example, both KCNQ1 and hERG possess highly conserved proline (P320 and P632 respectively) and threonine residues (T322 and T634 respectively) in this region. Analogous mutations in this region will be made in each channel and studied using an In/On-Cell Western assay to determine effects on channel trafficking to the surface membrane and with whole-cell patch-clamp to evaluate functional expression [4,5]. This comparison of analogous positions in the two channels will establish whether the regions studied are particularly vulnerable to pathological variation.