Nutrient associated changes in plasma membrane H+-ATPase activity of permeabilized Candida albicans cells

Nutrient stimulated H+ extrusion by cells and spheroplasts of Candida albicans and its underlying mechanism has been investigated. Glucose and glutamic acid stimulated extrusion by a factor of 6 and 1.4 respectively in cells, but had no effect on spheroplasts. Proline showed no H+ stimulation in cells, however, it stimulated spheroplasts 1.5 fold. ATPase activity of toluene-ethanol-Triton-X-100 (TET) permeabilized cells decreased by 20% following exposure to glucose and proline and 30% following exposure to glutamic acid. Permeabilized spheroplasts of Candida albicans showed drastic reduction in ATPase activity by 40%, 70% and 85% following exposure to glucose, proline and glutamic acid respectively. Externally added F-actin fully restored activity in the case of permeabilized cells and partly with spheroplasts suggesting that ATPase interacts with other membrane proteins during nutrient stimulation of cells.