Chloride channels in basolateral TAL membranes. XVIII. Phenylglyoxal induces functional mcCIC-Ka activity in basolateral MTAL membranes.
Cultured mouse MTAL cells contain more mRNA encoding the Cl- channel mcCIC-Ka, which mediates CTAL Cl- absorption, than mRNA encoding the Cl- channel mmCIC-Ka, which mediates MTAL Cl- absorption. mmCIC-Ka and mcCIC-Ka have three functional differences: 1) mmCIC-Ka open time probability, Po, increases with increasing cytosolic Cl-, but variations in cytosolic Cl- do not affect Po in mcCIC-Ka; 2) mmCIC-Ka is gated by (ATP + PKA), while (ATP + PKA) have no effect on Po in mcCIC-Ka; and 3) mmCIC-Ka channels have single-ion occupancy, while mcCIC-Ka channels have multi-ion occupancy. Using basolateral vesicles from MTAL cells fused into bilayers, we evaluated the effects of 1 mM cytosolic phenylglyoxal (PGO), which binds covalently to lysine or arginine, on Cl- channels. With PGO pretreatment, Cl- channels were uniformly not gated either with increases in cytosolic-face Cl- or with (ATP + PKA) at 2 mM cytosolic-face Cl-; and they exhibited multi-ion occupancy kinetics typical for mcCIC-Ka channels. Thus, in basolateral MTAL membranes, blockade of Cl- access to arginine or lysine residues on mmCIC-Ka by PGO results in Cl- channels having the functional characteristics of mcCIC-Ka channels.
Winters
C J
CJ
Division of Nephrology, Department of Internal Medicine, University of Arkansas College of Medicine and The Central Arkansas Veterans Healthcare System, Little Rock, Arkansas, USA.
Andreoli
T E
TE
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D001485:Basement Membrane / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D018118:Chloride Channels / Q000235:genetics / Q000378:metabolism*; D002712:Chlorides / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D003600:Cytosol; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D015640:Ion Channel Gating; D007679:Kidney Medulla / Q000187:drug effects* / Q000378:metabolism; D008051:Lipid Bilayers / Q000378:metabolism; D008564:Membrane Potentials; D051379:Mice; D010658:Phenylglyoxal / Q000494:pharmacology*; D015221:Potassium Channels / Q000235:genetics / Q000378:metabolism*; D011817:Rabbits
D018118:Chloride Channels; D002712:Chlorides; D004791:Enzyme Inhibitors; D008051:Lipid Bilayers; D015221:Potassium Channels; D000255:Adenosine Triphosphate; D017868:Cyclic AMP-Dependent Protein Kinases; D010658:Phenylglyoxal