Protein kinase C epsilon regulates gamma-aminobutyrate type A receptor sensitivity to ethanol and benzodiazepines through phosphorylation of gamma2 subunits.
Ethanol enhances gamma-aminobutyrate (GABA) signaling in the brain, but its actions are inconsistent at GABA(A) receptors, especially at low concentrations achieved during social drinking. We postulated that the epsilon isoform of protein kinase C (PKCepsilon) regulates the ethanol sensitivity of GABA(A) receptors, as mice lacking PKCepsilon show an increased behavioral response to ethanol. Here we developed an ATP analog-sensitive PKCepsilon mutant to selectively inhibit the catalytic activity of PKCepsilon. We used this mutant and PKCepsilon(-/-) mice to determine that PKCepsilon phosphorylates gamma2 subunits at serine 327 and that reduced phosphorylation of this site enhances the actions of ethanol and benzodiazepines at alpha1beta2gamma2 receptors, which is the most abundant GABA(A) receptor subtype in the brain. Our findings indicate that PKCepsilon phosphorylation of gamma2 regulates the response of GABA(A) receptors to specific allosteric modulators, and, in particular, PKCepsilon inhibition renders these receptors sensitive to low intoxicating concentrations of ethanol.
Qi
Zhan-Heng
ZH
Ernest Gallo Clinic and Research Center, Department of Neurology, University of California-San Francisco, 5858 Horton Street, Emeryville, CA 94608, USA.
Song
Maengseok
M
Wallace
Melisa J
MJ
Wang
Dan
D
Newton
Philip M
PM
McMahon
Thomas
T
Chou
Wen-Hai
WH
Zhang
Chao
C
Shokat
Kevan M
KM
Messing
Robert O
RO
D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D000494:Allosteric Regulation; D000818:Animals; D001569:Benzodiazepines / Q000494:pharmacology*; D002478:Cells, Cultured; D004789:Enzyme Activation; D000431:Ethanol / Q000494:pharmacology*; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D009154:Mutation / Q000235:genetics; D010766:Phosphorylation / Q000187:drug effects; D051744:Protein Kinase C-epsilon / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D011725:Pyridines / Q000494:pharmacology; D011963:Receptors, GABA-A / Q000235:genetics / Q000378:metabolism*; D012680:Sensitivity and Specificity; D012694:Serine / Q000235:genetics / Q000378:metabolism; D000077334:Zolpidem
D047428:Protein Kinase Inhibitors; D021122:Protein Subunits; D011725:Pyridines; D011963:Receptors, GABA-A; D001569:Benzodiazepines; D000431:Ethanol; D012694:Serine; D000077334:Zolpidem; D000255:Adenosine Triphosphate; D051744:Protein Kinase C-epsilon