Premium
Brain‐type creatine kinase activates neuron‐specific K + ‐Cl – co‐transporter KCC2
Author(s) -
Inoue Koichi,
Yamada Junko,
Ueno Shinya,
Fukuda Atsuo
Publication year - 2006
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.2005.03560.x
Subject(s) - depolarization , extracellular , excitatory postsynaptic potential , chemistry , intracellular , inhibitory postsynaptic potential , cotransporter , symporter , glycine , creatine , reversal potential , wild type , hek 293 cells , neuron , transfection , receptor , biophysics , microbiology and biotechnology , transporter , biology , biochemistry , patch clamp , neuroscience , amino acid , mutant , gene , sodium , organic chemistry
GABA, a major inhibitory neurotransmitter in the adult CNS, is excitatory at early developmental stages as a result of the elevated intracellular Cl – concentration ([Cl – ] i ). This functional switch is primarily attributable to the K + ‐Cl – co‐transporter KCC2, the expression of which is developmentally regulated in neurons. Previously, we reported that KCC2 interacts with brain‐type creatine kinase (CKB). To elucidate the functional significance of this interaction, HEK293 cells were transfected with KCC2 and glycine receptor α2 subunit, and gramicidin‐perforated patch‐clamp recordings were performed to measure the glycine reversal potential (E gly ), giving an estimate of [Cl – ] i . KCC2‐expressing cells displayed the expected changes in E gly following alterations in the extracellular K + concentration ([K + ] o ) or administration of an inhibitor of KCCs, suggesting that the KCC2 function was being properly assessed. When added into KCC2‐expressing cells, dominant‐negative CKB induced a depolarizing shift in E gly and reduced the hyperpolarizing shift in E gly seen in response to a lowering of [K + ] o compared with wild‐type CKB. Moreover, 2,4‐dinitrofluorobenzene (DNFB), an inhibitor of CKs, shifted E gly in the depolarizing direction. In primary cortical neurons expressing CKB, the GABA reversal potential was also shifted in the depolarizing direction by DNFB. Our findings suggest that, in the cellular micro‐environment, CKB activates the KCC2 function.