コウボ エキホウマク ATPase ノ コウゾウ ト キノウ

The yeast vacuolar membrane H+-ATPase (V-ATPase) is the first member of "vacuolar type" ATPase family that has been successively identified in various endocytic and exocytic membrane compartments of eukaryotic cells. The V-ATPase is a multisubunit complex composed of an integral membrane Vo sector and a peripherally associated V1 sector, the two of which are joined together with the V1-Vo bridging component. Upon ATP hydorolysis, the enzyme induces an inward current of 100 pA and generates the proton motive force of 180 mV, interior acidic and inside positive, across the vacuolar membrane. The V-ATPase family performs diverse cellular functions and maintains pH and cation homeostasis in the lumens of organelles, in the cytosol and even in the extracellular milieu. The importance of being acid in these cellular compartments has been highlighted in various cellular events such as vegetative growth, cell transformation, differentiation, metamorphosis and apoptosis