A high-affinity, calmodulin-dependent Ca2+ pump in the basal-lateral plasma membranes of kidney cortex.
A purified preparation of kidney basolateral membrane vesicles is capable of ATP-dependent Ca2+ uptake. The reaction has high affinity for Ca2+ (Km about 0.1 microM) and a V of 5.8 nmol Ca2+ X mg-1 protein X min-1 in the predominantly right-side-out vesicular preparation used. It is inhibited by vanadate (K0.5 about 5 microM) and by anti-calmodulin drugs. A stimulatory effect of calmodulin is visible in membranes depleted of the activator. Exposure of basolateral membranes to 125I-azido-modified calmodulin results in the specific labeling of a membrane protein of Mr 141 000, which is tentatively suggested to be the Ca2+-pumping ATPase.
D000255:Adenosine Triphosphate / Q000502:physiology; D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D002147:Calmodulin / Q000378:metabolism*; D002148:Calmodulin-Binding Proteins; D002462:Cell Membrane / Q000378:metabolism; D007672:Kidney Cortex / Q000378:metabolism*; D010749:Phosphoprotein Phosphatases / Q000302:isolation & purification*; D010777:Photochemistry; D051381:Rats; D012964:Sodium / Q000494:pharmacology
D002147:Calmodulin; D002148:Calmodulin-Binding Proteins; D000255:Adenosine Triphosphate; D012964:Sodium; D010749:Phosphoprotein Phosphatases; D002118:Calcium