Group N.G. Greeff

from: 1.2.1973 - 31.10.2009
Our work concerns the gating processes in voltage dependent channels that are the basis for the excitation in nerve or muscle. We express channel proteins heterologously in frog oocytes after injection of wild-type RNA or after molecular engineering the coding DNA at strategic positions. The mutated channels are produced to modify functionally important regions in the gating machinery or to track their structural changes by attached fluorescent probes. We study channel function using biophysical techniques such as voltage-clamp and fluorescence microscopy. One of the 4 voltage-sensors in the sodium channel was shown to control the inactivation, a process which is central for the termination of the fast nerve excitation. By comparing ionic current and gating-current, the amount of silent channels which gate but do not open is determined. With fluorescence markers the density and distribution of channels is studied and changes in fluorescence intensity indicate structural changes.