title: Glyceraldehyde-3-phosphate dehydrogenase is a GABAA receptor kinase linking glycolysis to neuronal inhibition.
abstract: Protein phosphorylation is crucial for regulating synaptic transmission. We describe a novel mechanism for the phosphorylation of the GABA(A) receptor, which mediates fast inhibition in the brain. A protein copurified and coimmunoprecipitated with the phosphorylated receptor alpha1 subunit; this receptor-associated protein was identified by purification and microsequencing as the key glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Molecular constructs demonstrated that GAPDH directly phosphorylates the long intracellular loop of GABA(A) receptor alpha1 subunit at identified serine and threonine residues. GAPDH and the alpha1 subunit were found to be colocalized at the neuronal plasma membrane. In keeping with the GAPDH/GABA(A) receptor molecular association, glycolytic ATP produced locally at plasma membranes was consumed for this alpha1 subunit phosphorylation, possibly within a single macrocomplex. The membrane-attached GAPDH is thus a dual-purpose enzyme, a glycolytic dehydrogenase, and a receptor-associated kinase. In acutely dissociated cortical neurons, the rundown of the GABA(A) responses was essentially attributable to a Mg(2+)-dependent phosphatase activity, which was sensitive to vanadate but insensitive to okadaic acid or fluoride. Rundown was significantly reduced by the addition of GAPDH or its reduced cofactor NADH and nearly abolished by the addition of its substrate glyceraldehyde-3-phosphate (G3P). The prevention of rundown by G3P was abolished by iodoacetamide, an inhibitor of the dehydrogenase activity of GAPDH, indicating that the GABA(A) responses are maintained by a glycolysis-dependent phosphorylation. Our results provide a molecular mechanism for the direct involvement of glycolysis in neurotransmission.
authors.affiliation: Laboratory of Molecular Neurobiology and Pharmacology, Institut National de la Santé et de la Recherche Médicale Unité 573, F-75014 Paris, France. jacques.laschet@broca.inserm.fr
authors.forename: Jacques J
authors.initials: JJ
authors.lastname: Laschet
authors.forename: Frédéric
authors.initials: F
authors.lastname: Minier
authors.forename: Irène
authors.initials: I
authors.lastname: Kurcewicz
authors.forename: Michel H
authors.initials: MH
authors.lastname: Bureau
authors.forename: Suzanne
authors.initials: S
authors.lastname: Trottier
authors.forename: Freddy
authors.initials: F
authors.lastname: Jeanneteau
authors.forename: Nathalie
authors.initials: N
authors.lastname: Griffon
authors.forename: Bart
authors.initials: B
authors.lastname: Samyn
authors.forename: Jozef
authors.initials: J
authors.lastname: Van Beeumen
authors.forename: Jacques
authors.initials: J
authors.lastname: Louvel
authors.forename: Pierre
authors.initials: P
authors.lastname: Sokoloff
authors.forename: René
authors.initials: R
authors.lastname: Pumain
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology; D000595:Amino Acid Sequence; D000818:Animals; D001923:Brain Chemistry; D019556:COS Cells; D002417:Cattle; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology; D002522:Chlorocebus aethiops; D011756:Diphosphates / Q000494:pharmacology; D005986:Glyceraldehyde 3-Phosphate / Q000494:pharmacology; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000494:pharmacology / Q000502:physiology*; D006019:Glycolysis / Q000502:physiology*; D006624:Hippocampus / Q000166:cytology; D007460:Iodoacetamide / Q000494:pharmacology; D008274:Magnesium / Q000494:pharmacology; D008969:Molecular Sequence Data; D009243:NAD / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects* / Q000201:enzymology; D010766:Phosphorylation / Q000187:drug effects; D025941:Protein Interaction Mapping; D011499:Protein Processing, Post-Translational / Q000187:drug effects*; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000502:physiology*; D011817:Rabbits; D051381:Rats; D017207:Rats, Sprague-Dawley; D011963:Receptors, GABA-A / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D009435:Synaptic Transmission / Q000187:drug effects* / Q000502:physiology; D014162:Transfection
chemical_list: D011756:Diphosphates; D011963:Receptors, GABA-A; D011993:Recombinant Fusion Proteins; D009243:NAD; D005986:Glyceraldehyde 3-Phosphate; D000244:Adenosine Diphosphate; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D017346:Protein Serine-Threonine Kinases; D008274:Magnesium; D007460:Iodoacetamide