Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.6.3.1 (Mg2+-ATPase)
 1,484 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Rats were provided a normal laboratory diet or a low Ca.vitamin D-deficient diet. After the administration of 1 alpha-hydroxycholecalciferol, mitochondria, microsomes and slices were prepared from kidney cortex of both control and treated rats. When 1 alpha-hydroxycholecalciferol was given to normal and low Ca.vitamin D-deficient rats, Ca accumulation in mitochondria was stimulated during 30 minutes and the high calcium content was maintained at the subsequent incubation. There was a significant decrease of mitochondrial Ca2+-ATPase and Mg2+-ATPase activities with low Ca.vitamin D depletion, but both enzyme activities were restored by 1 alpha-hydroxycholecalciferol treatment of the depleted rats. Ca2+-ATPase and Mg2+-ATPase activities of microsomes were not altered with the administration of 1 alha-hydroxycholecalciferol. In contrast to results of mitochondrial Ca transport, changes in Ca influx and efflux of slices were not significant in response to the treatment of low Ca.vitamin D-deficient rats with 1 alpha-hydroxycholecalciferol. The results of the present study suggest that 1 alpha-hydroxycholecalciferol plays a role in the process of Ca accumulation and ATP hydrolysis of mitochondria in kidney cortex.
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PMID:[Effect of 1 alpha-hydroxycholecalciferol on cellular calcium metabolism of kidney cortex (author's transl)]. 15 63

In an effort to extend our studies on Ca2+ pumps to animal models, we developed a new monoclonal antibody (5F10) prepared against the human erythrocyte Ca2+-Mg2+-adenosinetriphosphatase (ATPase) that recognizes a protein of approximately 140 kDa in rat kidney homogenates. Enzyme-linked immunosorbent assays show that monoclonal antibody 5F10 binds purified Ca2+-Mg2+-ATPase and rat kidney membrane extracts in a concentration-dependent manner. In paraffin-embedded tissue sections, antibody 5F10 binds to an epitope in the basolateral membranes of rat kidney distal convoluted tubule principal cells. The antibody does not bind to intercalated cells. The latter cells were characterized by the presence of large amounts of carbonic anhydrase C. Polyclonal antibodies directed against chick intestinal 28-kDa vitamin D-dependent calcium binding protein (28-kDa CaBP) also bind epitopes in distal convoluted tubule cells, connecting tubules, and portions of collecting duct but not intercalated cells. Western blot and 45Ca blot analysis of renal cytosolic proteins showed that the polyclonal 28-kDa CaBP-directed antibody detects a protein which also binds calcium. Western blot analysis with monoclonal antibody 5F10 shows binding to both the authentic purified erythrocyte Ca2+ pump (approximately 138 kDa) and to tryptic fragments of this pump. Antibody JA3, previously used for staining of human kidney tubules, reacts with a different set of tryptic fragments, showing that the two antibodies are directed against different regions or conformational determinants on the pump molecule. We show that Ca2+-Mg2+-ATPase and 28-kDa CaBP are present in the principal cells of the distal convoluted tubule of the rat and are absent in intercalated cells.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Plasma membrane calcium pump and 28-kDa calcium binding protein in cells of rat kidney distal tubules. 255 40

Renal proximal tubule cells adapt to dietary phosphate (Pi) restriction by increasing Pi transport independent of parathyroid hormone, vitamin D metabolites, or serum Ca2+. To determine the underlying cellular mechanism(s), brush border (BBM) and basolateral membranes (BLM) were isolated from growing male rats fed a synthetic diet containing variable levels of Pi (0.1-1.4%). Dietary Pi restriction was without effect on either BBM or BLM total lipid phosphorus, individual phospholipid species, or BLM Na+-K+-ATPase specific activity. However, dietary Pi restriction (0.1 vs. 1.0%) did cause a significant reduction in BBM but not BLM cholesterol (0.45 vs. 0.41 mumol/mg protein). Brush border membrane cholesterol was inversely correlated with the tubular reabsorption of Pi (r = 0.77, P less than 0.01) over a broad range (99.9-46.2%). Arrhenius analysis of two intrinsic BBM enzymes revealed a significant reduction in the breakpoint temperature for alkaline phosphatase but no change for Mg2+-ATPase. Fluorescence polarization studies showed increased BBM inner core fluidity due to an alteration in neutral lipids but not phospholipid, fatty acid, or protein membrane components. These data demonstrate that the BBM can regulate its cholesterol content independent of the BLM. Furthermore, they suggest that adaptation to dietary Pi restriction involves a reduction in BBM cholesterol, which may be mediated by an increase in membrane fluidity.
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PMID:Renal apical membrane cholesterol and fluidity in regulation of phosphate transport. 316 Feb 47