Chiu Shuen Hui, Ph.D.
Professor Emeritus - Retired: July 2006
Department of Cellular & Integrative Physiology
E-mail: cshui @ iupui.edu
Education / Training
- 1966, B.S., University of Hong Kong, Hong Kong, China
- 1973, Ph.D., M.I.T., Cambridge, Massachusetts
- Postdoctoral Fellowship, Yale University, Connecticut
Calcium ions are vital in the activation of contraction in muscle. My research has been and will be focused on understanding how calcium ions are released from the internal stores in skeletal muscle. When a muscle fiber is stimulated, some electrical currents can be detected in the outer membranes and are believed to be due to the movement of some voltage sensors. This current provides the trigger for calcium release. I have been studying this triggering current with electrophysiological technique. I found that the triggering current is actually multi-component. My research will continue to be focused on the elucidation of the physiological roles of the various components.
The triggering current activates release of calcium ions from the internal stores to the myoplasm. The released calcium ions can be monitored by loading the myoplasm with a calcium indicator which changes absorbance or fluorescence upon binding with calcium ions. I have been studying this signal with a photometric device which measures the average absorbance change over many sarcomeres. I will continue to study this signal with absorbance indicators, which provide relatively faithful kinetic information about the global calcium release signal.
Because of the specific location of the calcium release channels inside a muscle fiber, the rise in calcium ion concentration in the myoplasm is not homogeneous but localized around the calcium release channels. The mapping of this localized signal requires an apparatus that can detect light with sub-micron resolution. This measurement is possible with the help of a laser scanning confocal microscope. With this technique, calcium release is found to be comprised of very brief, localized events that are called calcium sparks. Each spark is believed to arise from calcium release through a fundamental release unit containing just a few calcium release channels. I have been studying the mechanism underlying the generation of calcium sparks and probing the gating properties of the calcium release channels with the help of a specific ligand for the channel called ryanodine and its analogs. This line of research will likely be my major research focus in the next few years.
Selected Recent Publications
Hui, C.S. and Chen, W. (1997). Charge movement in cut twitch fibers of Rana temporaria containing 0.1 mM EGTA. J. Physiol. 503, 563-570.
Hui, C.S. (1998). A slow calcium dependent component of charge movement in Rana temporaria cut twitch fibers. J. Physiol. 509.3, 869-885.
Hui, C.S. (1999). Calcium release in frog cut twitch fibers exposed to different ionic environments under voltage clamp. Biophys. J. 77, 2123-2136.
Hui, C.S., Bidasee, K.R. and Besch, H.R., Jr. (2001). Effects of ryanodine on calcium sparks in cut twitch fibres of Rana temporaria. J. Physiol. 534.2, 327-342.
Hui, C.S., Besch, H.R., Jr. and Bidasee, K.R. (2004). Effects of ryanoid on spontaneous and depolarization-evoked calcium release events in frog muscle. Biophys. J. 87, 243-255.
Hui, C.S. (2005). Association of the I(gamma) and I(delta) charge movement components with calcium release in frog skeletal muscle. Biophys. J. 88, 1030-1045.
Last update: 5/07/2009