Animal plasma membrane energization by proton-motive V-ATPases.
Proton-translocating, vacuolar-type ATPases, well known energizers of eukaryotic, vacuolar membranes, now emerge as energizers of many plasma membranes. Just as Na(+) gradients, imposed by Na(+)/K(+) ATPases, energize basolateral plasma membranes of epithelia, so voltage gradients, imposed by H(+) V-ATPases, energize apical plasma membranes. The energized membranes acidify or alkalinize compartments, absorb or secrete ions and fluids, and underwrite cellular homeostasis. V-ATPases acidify extracellular spaces of single cells such as phagocytes and osteoclasts and of polarized epithelia, such as vertebrate kidney and epididymis. They alkalinize extracellular spaces of lepidopteran midgut. V-ATPases energize fluid secretion by insect Malpighian tubules and fluid absorption by insect oocytes. They hyperpolarize external plasma membranes for Na(+) uptake by amphibian skin and fish gills. Indeed, it is likely that ion uptake by osmotically active membranes of all fresh water organisms is energized by V-ATPases. Awareness of plasma membrane energization by V-ATPases provides new perspectives for basic science and presents new opportunities for medicine and agriculture.
Wieczorek
H
H
Department of Biology/Chemistry, University of Osnabrück, D-49069, Osnabrück, Germany.
Brown
D
D
Grinstein
S
S
Ehrenfeld
J
J
Harvey
W R
WR
D000818:Animals; D002462:Cell Membrane / Q000201:enzymology* / Q000378:metabolism; D004064:Digestive System / Q000201:enzymology; D004734:Energy Metabolism; D007668:Kidney / Q000201:enzymology; D008297:Male; D010010:Osteoclasts / Q000378:metabolism; D010586:Phagocytes / Q000378:metabolism; D017494:Proton Pumps / Q000378:metabolism; D006180:Proton-Translocating ATPases / Q000737:chemistry / Q000145:classification / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism; D013094:Spermatozoa / Q000201:enzymology; D025262:Vacuolar Proton-Translocating ATPases
D017494:Proton Pumps; D012964:Sodium; D025262:Vacuolar Proton-Translocating ATPases; D006180:Proton-Translocating ATPases