title: Distribution of membrane-bound cyclic AMP-dependent protein kinase in plasma membranes of cells of the kidney cortex.
abstract: Renal cortical plasms membranes were separated by free flow electrophoresis into luminal (brush border microvilli) and contraluminal (basal-lateral membrane) fractions. These membranes were found to contain an intrinsic, self-phosphorylating system which consists of a cyclic AMP-dependent protein kinase, a phosphorprotein phosphatase and the substrate(s) of these enzymes. The kinase, but not the phosphatase, was stimulated by cyclic AMP; maximal (1.7-fold) stimulation was effected at a cyclic AMP concentration of 0.1 muM. The degree of phosphorylation of the brush borders was six times greater than that of the basal-lateral membranes in the absence of cyclic AMP and 2.3-fold greater in the presence of cyclic AMP. This preferential phosphorylation of the luminal membrane by membrane-associated protein kinase(s) may play a role in the parathyroid hormone-mediated alterations of solute reabsorption in the proximal tubule.
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000494:pharmacology; D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology*; D000242:Cyclic AMP / Q000494:pharmacology*; D003600:Cytosol / Q000201:enzymology; D004789:Enzyme Activation / Q000187:drug effects; D007672:Kidney Cortex / Q000166:cytology* / Q000201:enzymology; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D010042:Ouabain / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology; D011485:Protein Binding; D011494:Protein Kinases / Q000378:metabolism*; D051381:Rats; D012964:Sodium / Q000494:pharmacology
chemical_list: D010042:Ouabain; D011189:Potassium Chloride; D000255:Adenosine Triphosphate; D012964:Sodium; D000242:Cyclic AMP; D011494:Protein Kinases; D000469:Alkaline Phosphatase; D000251:Adenosine Triphosphatases; D008274:Magnesium; D011188:Potassium