연사 : Dr. Bradley J. Baker (KIST)
Primary Investigator, Principal Scientist , World Class Institute, Center for Functional Connectomics. Korea Institute of Science and Technology
연제 : Resolving Voltage, pH, and Electrical Synapses with Genetically-Encoded Fluorescent Sensors of Membrane Potential
일시 : 2015년 5월 15일 (금) 오후 4시
장소 : 하나과학관 A동 101호
초청교수 : 백자현교수
Abstract
Genetically-encoded fluorescent sensors of membrane potential consist of a voltage sensing domain (VSD) fused to a fluorescent protein. Changes in membrane potential causes a conformational change in the VSD which is optically reported by changes in fluorescent intensities. Ideally, these sensors should have a very fast response time to resolve action potentials and extremely efficient plasma membrane targeting to maximize the signal-to-noise ratio of the fluorescent signal. The VSD from the voltage-sensing phosphatase gene family targets well to the plasma membrane but is somewhat slow with response times over 50 msec. By mutating charged residues in the VSD we have been able to reduce the response time to less than 10 msec. One sensor, 봉우리 (Bongwoori), is capable of resolving action potentials at 60 hertz. Furthermore, we have been able to adjust the voltage sensitivity to bias the optical response to action potentials versus variations in membrane potential due to sub-threshold synaptic activity. Efforts to identify novel VSDs from other gene families have resulted a novel sensor파도 (Pado) which is capable of modulating and optically reporting intracellular pH which may lead to mapping of electrical synapses. We have also developed a tryptophan scan that inhibits movement of S4 in one direction which will potentially focus the voltage sensitivity to specific types of neuronal activity.