HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

J. Biol. Chem., Vol. 281, Issue 51, 39205-39216, December 22, 2006

This Article Full Text Full Text (PDF) Supplemental Data All Versions of this Article: 281/51/39205    most recent M606287200v1 Submit a Letter to Editor Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Lee, J.-Y. Articles by Lee, S.-H. Search for Related Content PubMed PubMed Citation Articles by Lee, J.-Y. Articles by Lee, S.-H. Social Bookmarking                      What's this?

Protein Kinase C-dependent Enhancement of Activity of Rat Brain NCKX2 Heterologously Expressed in HEK293 Cells^*

Ju-Young Lee¹, Frank Visser², Jae Sung Lee¹, Kyu-Hee Lee¹, Jae-Won Soh^¶, Won-Kyung Ho, Jonathan Lytton³, and Suk-Ho Lee⁴

From the National Research Laboratory for Cell Physiology, Department of Physiology, Seoul National University College of Medicine, 28 Yongon-Dong, Chongno-Ku, Seoul 110-799, South Korea, the ^¶Biomedical Research Center for Signal Transduction Networks, Department of Chemistry, Inha University, Inchon 402-751, South Korea, and the Libin Cardiovascular Institute of Alberta, Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta T2N 4N1, Canada

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 -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 PKC (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, -phorbol myristate acetate (PMA), but not 4-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.

Received for publication, June 30, 2006 , and in revised form, October 10, 2006.

^* This work was supported in part by the Brain Research Center of the 21st Century Frontier Research Program (Grant M103KV010008-06K2201-00810) funded by the Ministry of Science and Technology, the Republic of Korea (to S.-H. L.) and from the Canadian Institutes of Health Research (Grant FRN 15035) and the Alberta Heritage Foundation for Medical Research (to J. L.). The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

The on-line version of this article (available at http://www.jbc.org) contains supplemental Figs. S1–S4 and Table S1.

¹ Postgraduate students supported by Program BK21 from the Ministry of Education.

² Holds postdoctoral fellowships from the Canadian Institutes of Health Research and the Alberta Heritage Foundation for Medical Research.

³ A scientist of the Alberta Heritage Foundation for Medical Research.

⁴ To whom correspondence should be addressed. Tel.: 82-2-740-8222; Fax: 82-2-763-9667; E-mail: leesukho{at}snu.ac.kr.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				F. Visser and J. Lytton K+-Dependent Na+/Ca2+ Exchangers: Key Contributors to Ca2+ Signaling Physiology, June 1, 2007; 22(3): 185 - 192. [Abstract] [Full Text] [PDF]

				F. Visser, V. Valsecchi, L. Annunziato, and J. Lytton Analysis of Ion Interactions with the K+ -dependent Na+/Ca+ Exchangers NCKX2, NCKX3, and NCKX4: IDENTIFICATION OF THR-551 AS A KEY RESIDUE IN DEFINING THE APPARENT K+ AFFINITY OF NCKX2 J. Biol. Chem., February 16, 2007; 282(7): 4453 - 4462. [Abstract] [Full Text] [PDF]