Analysis of Ion Channel Dynamics by Single Molecule Tracking in Live Cells

Abstract

Protein dynamics play an important role in signal transduction in association with their activation mechanisms, functions, and so on. Single molecule tracking technique have been widely used for investigating diffusion behavior of protein in live cells. Especially membrane proteins have been studied since they are important to understand cell responding to the surroundings. However, not many ion channel proteins such as AMPAR, NMDAR, etc., have been monitored due to their complex system. Here, we observed ionotropic glutamate receptor in neuroblastoma SH-SY5Y cell using single-molecule imaging. The diffusion coefficient of the receptor was significantly low because the receptor has four subunits (tetramers) and each subunit possesses a four transmembrane domain. Furthermore, we also analyzed interaction between subunits using single molecule tracking, further investigation of the protein dynamics of the membrane proteins such as ionotropic receptors, their structure and protein activation mechanism will be possible.