Protein kinase A activation phosphorylates the rat ClC-2 Cl- channel but does not change activity.
Phosphorylation-dependent events have been shown to modulate the activity of several members of the mammalian CLC Cl- channel gene family, including the inward rectifier ClC-2. In the present study we investigated the regulation of rat ClC-2 expressed in the TSA-201 cell line (a transformed HEK293 cell line that stably expresses the SV40 T-antigen) by protein kinases. Protein kinase A activation phosphorylated ClC-2 in vivo, whereas stimulation of protein kinase C with phorbol 12-myristate 13-acetate did not. In vitro labeling studies confirmed that protein kinase A could directly phosphorylate ClC-2, and that protein kinase C and Ca2+/calmodulin-dependent protein kinase II did not. Nevertheless, protein kinase A-dependent phosphorylation of CLC-2 failed to regulate either the magnitude or the kinetics of the hyperpolarization-activated Cl- currents. Considered together, we demonstrate that protein kinase A activation results in the phosphorylation of rat ClC-2 in vivo, but this event is independent of Cl- channel activity.
Park
K
K
Center for Oral Biology, Aab Institute of Biomedical Sciences, Rochester, NY 14642, USA.
Begenisich
T
T
Melvin
J E
JE
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D002461:Cell Line, Transformed; D018118:Chloride Channels / Q000235:genetics / Q000378:metabolism*; D002712:Chlorides / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000235:genetics / Q000378:metabolism*; D004789:Enzyme Activation; D004847:Epithelial Cells / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D008564:Membrane Potentials / Q000502:physiology*; D018408:Patch-Clamp Techniques; D010766:Phosphorylation; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D051381:Rats; D013755:Tetradecanoylphorbol Acetate / Q000031:analogs & derivatives / Q000494:pharmacology*; D014162:Transfection
C505032:CFTR protein, human; D018118:Chloride Channels; D002712:Chlorides; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; C020922:4-O-methyl-12-O-tetradecanoylphorbol 13-acetate; D000255:Adenosine Triphosphate; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D013755:Tetradecanoylphorbol Acetate