title: WNK1-regulated inhibitory phosphorylation of the KCC2 cotransporter maintains the depolarizing action of GABA in immature neurons.
abstract: Activation of Cl(-)-permeable γ-aminobutyric acid type A (GABAA) receptors elicits synaptic inhibition in mature neurons but excitation in immature neurons. This developmental "switch" in the GABA function depends on a postnatal decrease in intraneuronal Cl(-) concentration mediated by KCC2, a Cl(-)-extruding K(+)-Cl(-) cotransporter. We showed that the serine-threonine kinase WNK1 [with no lysine (K)] forms a physical complex with KCC2 in the developing mouse brain. Dominant-negative mutation, genetic depletion, or chemical inhibition of WNK1 in immature neurons triggered a hyperpolarizing shift in GABA activity by enhancing KCC2-mediated Cl(-) extrusion. This increase in KCC2 activity resulted from reduced inhibitory phosphorylation of KCC2 at two C-terminal threonines, Thr(906) and Thr(1007). Phosphorylation of both Thr(906) and Thr(1007) was increased in immature versus mature neurons. Together, these data provide insight into the mechanism regulating Cl(-) homeostasis in immature neurons, and suggest that WNK1-regulated changes in KCC2 phosphorylation contribute to the developmental excitatory-to-inhibitory GABA sequence.
authors.affiliation: Institut de Neurobiologie de la Méditerranée (INMED), INSERM Unité 901, 13273 Marseille, France. Aix-Marseille Université, UMR 901, 13273 Marseille, France.
authors.forename: Perrine
authors.initials: P
authors.lastname: Friedel
authors.affiliation: Department of Neurosurgery, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA. kkahle@enders.tch.harvard.edu igor.medyna@inserm.fr.
authors.forename: Kristopher T
authors.initials: KT
authors.lastname: Kahle
authors.affiliation: UK Medical Research Council Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK.
authors.forename: Jinwei
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Howard Hughes Medical Institute and Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, CA 94143-0450, USA.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Hertz
authors.affiliation: Institut de Neurobiologie de la Méditerranée (INMED), INSERM Unité 901, 13273 Marseille, France. Aix-Marseille Université, UMR 901, 13273 Marseille, France.
authors.forename: Lucie I
authors.initials: LI
authors.lastname: Pisella
authors.affiliation: Aix-Marseille Université, UMR 901, 13273 Marseille, France. Plateforme Post-Génomique, INMED, 13273 Marseille, France.
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Buhler
authors.affiliation: Aix-Marseille Université, UMR 901, 13273 Marseille, France. Plateforme Post-Génomique, INMED, 13273 Marseille, France.
authors.forename: Fabienne
authors.initials: F
authors.lastname: Schaller
authors.affiliation: Department of Neurosurgery, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA.
authors.forename: JingJing
authors.initials: J
authors.lastname: Duan
authors.affiliation: Department of Neurosurgery, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Arjun R
authors.initials: AR
authors.lastname: Khanna
authors.affiliation: School of Biochemistry, University of Bristol, Bristol BS8 1TH, UK.
authors.forename: Paul N
authors.initials: PN
authors.lastname: Bishop
authors.affiliation: Howard Hughes Medical Institute and Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, CA 94143-0450, USA.
authors.forename: Kevan M
authors.initials: KM
authors.lastname: Shokat
authors.affiliation: Institut de Neurobiologie de la Méditerranée (INMED), INSERM Unité 901, 13273 Marseille, France. Aix-Marseille Université, UMR 901, 13273 Marseille, France. kkahle@enders.tch.harvard.edu igor.medyna@inserm.fr.
authors.forename: Igor
authors.initials: I
authors.lastname: Medina
mesh_terms: D000818:Animals; D004622:Embryo, Mammalian / Q000166:cytology / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D008564:Membrane Potentials / Q000502:physiology*; D051379:Mice; D015778:Minor Histocompatibility Antigens; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D016716:PC12 Cells; D010766:Phosphorylation / Q000502:physiology; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D027981:Symporters / Q000235:genetics / Q000378:metabolism*; D000076204:WNK Lysine-Deficient Protein Kinase 1; D005680:gamma-Aminobutyric Acid / Q000235:genetics / Q000378:metabolism*; D000096922:K Cl- Cotransporters
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D015778:Minor Histocompatibility Antigens; D017346:Protein Serine-Threonine Kinases; D027981:Symporters; D000076204:WNK Lysine-Deficient Protein Kinase 1; D005680:gamma-Aminobutyric Acid; D000096922:K Cl- Cotransporters; C498743:WNK1 protein, human; C498744:Wnk1 protein, mouse; C410410:Wnk1 protein, rat