Title: Structural Studies of Tetrameric Cation Channels

Speaker: Youxing Jiang (UT Southwestern)

Time: September 18 2016 (Sun) 8:30-9:30

Venue: R101, Jinguang Life Science Building, Peking University

Ion transfer across biological membranes is an essential physiological process mediated by ion channels, and is central to nerve excitation, muscle cell contraction, signal transduction, and hormone secretion. Ion channels are membrane proteins which, in a regulated fashion, open a hole in the lipid membrane and allow the free diffusion of ions down their electrochemical gradients. The immense physiological importance of ion channels is reflected in the fact that their dysfunction underlies a variety of disabling human diseases including seizures, deafness, ataxia, long QT syndrome, and cardiac arrhythmias.    Two fundamental properties are central to ion channel function: ion selectivity, which determines the passage of specific ions through the channel, and gating, which is the opening and closing of the channel pore in response to specific stimuli. A major focus of my lab is the study of these two fundamental properties among tetrameric cation channels. Members of this large ion channel family contain four membrane-spanning subunits forming a central pore for selective ion transfer. Specifically, our efforts to decipher ion selectivity mechanisms are focused on K + and non-selective channels, while our gating studies are centered on ligand-gated K + channels regulated by a conserved ligand binding RCK (Regulating the Conductance of K + ) domain. Our experimental approach utilizes protein crystallography to determine the three dimensional structures of the ion channels and electrophysiology to elucidate their biophysical properties.

Host: Zhonggang Jiao