The effects of level of expression of a jellyfish Shaker potassium channel: a positive potassium feedback mechanism

1. When jellyfish Shaker potassium channels (jShak2) are heterologously exp ressed in Xenopus oocytes at different levels they demonstrate density-depe ndent changes in electrical and kinetic properties of macroscopic currents. 2. The activation and inactivation properties of jShak2 channels depend on the extracellular potassium concentration. In this study we present experim ental data which show that expression-dependent changes in kinetic and elec trical properties of jShak2 macroscopic currents can be explained by the po sitive feedback effect of dynamic accumulation of K+ in the perimembranal s pace.