Browse

Protein kinase C-dependent enhancement of activity of rat brain NCKX2 heterologously expressed in HEK293 cells

Cited 13 time in Web of Science Cited 13 time in Scopus
Authors
Lee, Ju-Young; Visser, Frank; Lee, Jae Sung; Lee, Kyu-Hee; Soh, Jae-Won; Ho, Won-Kyung; Lytton, Jonathan; Lee, Suk-Ho
Issue Date
2006-10-14
Publisher
American Society for Biochemistry and Molecular Biology
Citation
J Biol Chem. 2006 Dec 22;281(51):39205-16. Epub 2006 Oct 12.
Keywords
AnimalsAntiporters/metabolismBinding SitesBrain/*enzymology/metabolismCalcium/metabolismElectrophysiologyEnzyme Activation*Gene Expression Regulation, EnzymologicHumansMutationPhosphorylationProtein Kinase C/metabolism/*physiologyProtein Structure, TertiaryRatsSodium-Calcium Exchanger/metabolism/*physiology
Abstract
Different members of the Na+/Ca2++K+ exchanger (NCKX) family are present in distinct brain regions, suggesting that they may have cell-specific functions. Many neuronal channels and transporters are regulated via phosphorylation. Regulation of the rat brain NCKXs by protein kinases, however, has not been described. Here, we report an increase in NCKX2 activity in response to protein kinase C (PKC) activation. Outward current of NCKX2 heterologously expressed in HEK293 cells was enhanced by beta-phorbol dibutyrate (PDBu), whereas PDBu had little effect on activity of NCKX3 or NCKX4. The PDBu-induced enhancement (PIE) of NCKX2 activity was abolished by PKC inhibitors and significantly reduced when the dominant negative mutant of PKCepsilon (K437R) was overexpressed. Moreover, PDBu accelerated the decay rate of the Ca2+ transient at the calyx of Held, where NCKX is the major Ca2+-clearance mechanism. Intracellular perfusion with alkaline phosphatase completely inhibited PIE. Consistently, beta-phorbol myristate acetate (PMA), but not 4alpha-PMA, induced a 3-fold stimulation of 32P incorporation into NCKX2 expressed in HEK293 cells. To investigate the sites involved, PIE of wild-type NCKX2 was compared with mutant NCKX2 in which the three putative PKC consensus sites were replaced with alanine, either individually or in combination. Double-site mutation involving Thr-476 (T166A/T476A and T476A/S504A) disrupted PIE, whereas single mutation of Thr-166, Thr-476, or Ser-504 or the double mutant T166A/S504A failed to completely prevent PIE. These findings suggest that PKC-mediated activation of NCKX2 is sensitive to mutation of multiple PKC consensus sites via a mechanism that may involve several phosphorylation events.
ISSN
0021-9258 (Print)
Language
English
URI
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=17038313

http://hdl.handle.net/10371/29636
DOI
https://doi.org/10.1074/jbc.M606287200
Files in This Item:
There are no files associated with this item.
Appears in Collections:
College of Medicine/School of Medicine (의과대학/대학원)Dept. of Physiology (생리학교실)Journal Papers (저널논문_생리학교실)
  • mendeley

Items in S-Space are protected by copyright, with all rights reserved, unless otherwise indicated.

Browse