Skeletal muscle contraction occurs within tens of milliseconds after electrical excitation of the muscle cell membrane. It requires the release of calcium ions from an internal store (the sarcoplasmic reticulum) into the myoplasm. The protein that mediates calcium release, the ryanodine receptor (RyR), is one of the largest and most complex channel proteins known to date. It closely interacts with several other polypeptides including a protein (the dihydropyridine receptor = DHPR) that senses the electrical field of the cell membrane.
AG Melzer, Research Topics
Our group investigates the function of proteins involved in calcium fluxes in skeletal muscle. Calcium inward currents, voltage sensor charge movements and calcium release are studied by a combination of electrophysiological techniques and microanalytical methods (microfluorometry). In addition to the rapid defined changes in membrane potentials by voltage clamp techniques we generate concentration changes of effector substances by means of intracellular and extracellular perfusion and by using UV flash photolysis. The signals are measured in both native muscle cells (fully differentiated or myocytes in culture) and cells heterologously expressing the proteins. In addition transgenic mice lacking proteins involved in EC coupling are studied.