The present address of the T. Kranz is the Psychobiology, Department of Behavioral Genetics, University of Trier, Johanniterufer 15, 54290 Trier, Germany.
Opposite effect of membrane raft perturbation on transport activity of KCC2 and NKCC1
Article first published online: 17 AUG 2009
© 2009 The Authors. Journal Compilation © 2009 International Society for Neurochemistry
Journal of Neurochemistry
Volume 111, Issue 2, pages 321–331, October 2009
How to Cite
Hartmann, A.-M., Blaesse, P., Kranz, T., Wenz, M., Schindler, J., Kaila, K., Friauf, E. and Nothwang, H. G. (2009), Opposite effect of membrane raft perturbation on transport activity of KCC2 and NKCC1. Journal of Neurochemistry, 111: 321–331. doi: 10.1111/j.1471-4159.2009.06343.x
- Issue published online: 23 SEP 2009
- Article first published online: 17 AUG 2009
- Received June 23, 2009; revised manuscript received July 4, 2009; accepted July 7, 2009.
- brain development;
- cation chloride cotransporter;
- chloride homeostasis;
- inhibitory synapse;
In the majority of neurons, the intracellular Cl− concentration is set by the activity of the Na+-K+-2Cl− cotransporter (NKCC1) and the K+-Cl− cotransporter (KCC2). Here, we investigated the cotransporters’ functional dependence on membrane rafts. In the mature rat brain, NKCC1 was mainly insoluble in Brij 58 and co-distributed with the membrane raft marker flotillin-1 in sucrose density flotation experiments. In contrast, KCC2 was found in the insoluble fraction as well as in the soluble fraction, where it co-distributed with the non-raft marker transferrin receptor. Both KCC2 populations displayed a mature glycosylation pattern. Disrupting membrane rafts with methyl-β-cyclodextrin (MβCD) increased the solubility of KCC2, yet had no effect on NKCC1. In human embryonic kidney-293 cells, KCC2 was strongly activated by a combined treatment with MβCD and sphingomyelinase, while NKCC1 was inhibited. These data indicate that membrane rafts render KCC2 inactive and NKCC1 active. In agreement with this, inactive KCC2 of the perinatal rat brainstem largely partitioned into membrane rafts. In addition, the exposure of the transporters to MβCD and sphingomyelinase showed that the two transporters differentially interact with the membrane rafts. Taken together, membrane raft association appears to represent a mechanism for co-ordinated regulation of chloride transporter function.