The localization of (Ca2+ or Mg2+)-ATPase in plasma membranes of renal proximal tubular cells

Molecular and biochemical mechanisms of chemically induced nephrotoxicity: a review

“…Direct interactions with Ca2+ transport are most commonly observed with divalent metals such as lead, ruthenium, cadmium, and others (32). Plasma membrane Ca2+-AT-Pase, in the kidney located at the brush border membrane (33), is a sulfhydryl-dependent enzyme which can be inactivated by thiol oxidation [e.g., by menadione (34)], mixed disulfide formation [e.g., by cystamine (35)], or covalent binding [e.g., by paracetamol (36)]. Na+/K+-ATPase also has been shown to be inhibited by several nephrotoxicants: e.g., by vanadium (37), mercury chloride (38), and gentamicin (39).…”

Identification and Partial Purification of (Ca2+ or Mg2+)‐ATPase in Renal Brush‐Border Membranes

“…A brush-border membrane fraction, prepared by free-flow electrophoresis of pig kidney cortex [17], was used to characterize the two divalent-cation-stimulated ATPases present in these membranes. The effect of 5 mh4 of several divalent cations on both ATPase activities is presented in Table 1.…”

“…First, contamination should be similar in preparations of both types of membranes of proximal tubular cells. With our preparations the (Ca2+ or MgZ+)-ATPase activity in basolateral membranes was always very low in comparison with brush-border membranes prepared from the same kidney [17]. Second, protein bands with a molecular mass of 75 kDa or 105 kDa (representative for the nonreduced and the reduced forms of thrombomodulin [42]) were not conspiciously stained on SDS/polyacrylamide gels of either brush-border or basolatera1 membrane preparations.…”

“…Microsomal fractions and brush-border membranes were prepared from pig kidney cortex by differential centrifugation and free-flow electrophoresis, as described by Van Erum et al [17]. Optimal solubilization was always determined at 4°C under equal conditions of time and concentrations for every detergent tested.…”