Potassium Channel Gating Youxing Jiang, UT Southwestern

Ion channels are membrane proteins that control the flow of ions such as K+, Na+, Ca2+, and Cl- across the cell membrane.  Ion Channel function underlies many biological processes such as the excitation of nerve and muscle cells, the secretion of hormones, and sensory transduction. There are two fundamental properties of ion channels: ion selectivity and gating of the pore.  Ion selectivity refers to the property that ion channels permit only specific ions through their pore; gating refers to the property that a channel opens and closes in response to a specific stimulus. There are two general gating mechanisms of cation channels: ligand gating and voltage gating.  In ligand-gated channels, a small molecule such as a neurotransmitter or second messenger binds to the channel and causes it to open.  In voltage gating, changes in the membrane voltage open and close the channel.  Here I will present the work of using both x-ray crystallography and electrophysiological tools to study the potassium channel gating.