WNK1-regulated inhibitory phosphorylation of the KCC2 cotransporter maintains the depolarizing action of GABA in immature neurons

TY - JOUR

T1 - WNK1-regulated inhibitory phosphorylation of the KCC2 cotransporter maintains the depolarizing action of GABA in immature neurons

AU - Friedel, Perrine

AU - Kahle, Kristopher T.

AU - Zhang, Jinwei

AU - Hertz, Nicholas

AU - Pisella, Lucie I.

AU - Buhler, Emmanuelle

AU - Schaller, Fabienne

AU - Duan, Jingjing

AU - Khanna, Arjun R.

AU - Bishop, Paul N.

AU - Shokat, Kevan M.

AU - Medina, Igor

PY - 2015/6/30

Y1 - 2015/6/30

N2 - Activation of Cl--permeable g-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, Thr906 and Thr1007. Phosphorylation of both Thr906 and Thr1007 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.

AB - Activation of Cl--permeable g-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, Thr906 and Thr1007. Phosphorylation of both Thr906 and Thr1007 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.

UR - https://www.scopus.com/pages/publications/84937821193

U2 - 10.1126/scisignal.aaa0354

DO - 10.1126/scisignal.aaa0354

M3 - Article

C2 - 26126716

AN - SCOPUS:84937821193

SN - 1945-0877

VL - 8

JO - Science Signaling

JF - Science Signaling

IS - 383

M1 - ra65

ER -