Structural Biology/Biochemistry Seminar
11:15 am – 12:30 pm | 112 KLB
Tuesday February 24, 2015
“On the Origin of Ion Selectivity in K Channels”
Dr. Youxing Jiang
W.W. Caruth, Jr. Scholar in Biomedical Research
University of Texas, Southwestern
Host: Dr. Huan-Xiang Zhou
- Ion channels and membrane transporters: The research of our laboratory has been focusing on the structural and functional studies of ion channels and transporters which control the flow of ions across the cell membrane. These proteins regulate many biological processes such as the excitation of nerve and muscle cells, the secretion of hormones, and sensory transduction.
- Ion selectivity of tetrameric cation Channels: To understand the structural basis of ion selectivity in tetrameric cation channels, we have been using the NaK channel as the model system to elucidate the basic principles of ion selectivity in CNG channels and K+ channels.
- Ion transporters: The study on ion transporters in the lab has been focused on Na+/Ca2+ exchangers (NCX) which are crucial membrane transporters in maintaining the homeostasis of cytosolic Ca2+ for cell signaling. With the determination of a high-resolution structure of an NCX protein from Methanococcus jannaschii (NCX_Mj), we now have a working model system to elucidate the structural basis and mechanistic details of ion exchange in NCX proteins.
- Ligand gating of cation channels: To study channel gating, the lab focuses on a group of ligand gated K+ channels that are regulated by a conserved ligand binding domain, the RCK domain. This group includes the majority of prokaryotic K+ channels and the eukaryotic high-conductance Ca2+-gated K+ channels (BK or maxiK).
- Our research approach is a combination of membrane protein X-ray crystallography, aimed at determining the three dimensional structure of the ion transporting proteins, and channel electrophysiology, to study the physiological functions of these proteins.