Increasing evidence indicates that potassium (K+) channels play important roles in the growth and development of human cancer. In the present study, we investigated the contribution of and the mechanism by which K+ channels control the proliferation and tumor development of U87-MG human glioma cells. A variety of K+ channel blockers and openers were used to differentiate the critical subtype of...

Large-conductance Ca2+-voltage-activated K+ channels (BK channels) control many key physiological processes, such as neurotransmitter release and muscle contraction. A signature feature of BK channels is that they have the largest single channel conductance of all K+ channels. Here we examine the mechanism of this large conductance. Comparison of the sequence of BK channels to lower-conductance...

HCN channels are thought to be structurally similar to Kv channels, but show much lower selectivity for K+. The approximately 3.3 A selectivity filter of K+ channels is formed by the pore-lining sequence XT(V/I)GYG, with X usually T, and is held stable by key residues in the P-loop. Differences in the P-loop sequence of HCN channels (eg. the pore-lining sequence L478C479IGYG) suggest these resi...

Long-term adaptation to a high-K diet is known to increase the density of conducting secretory K (SK) channels in the luminal membrane of the rat cortical collecting tubule (CCT). To examine whether these channels are involved in the short-term, day-to-day regulation of K secretion, we examined the density of K channels in animals fed a high-K diet for 6 or 48 h. CCTs were isolated and split op...

The molecular mechanisms by which higher plant cells take up K+ across the plasma membrane (plasmalemma) remain unknown. Physiological transport studies in a large number of higher plant cell types, including guard cells, have suggested that at least two distinct types of K(+)-uptake mechanisms exist, permitting low-affinity and high-affinity K+ accumulation, respectively. Recent patch clamp st...