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

J. Biol. Chem., Vol. 283, Issue 13, 8517-8526, March 28, 2008

This Article Full Text Full Text (PDF) Supplemental Data All Versions of this Article: 283/13/8517    most recent M707107200v1 Alert me when this article is cited 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 Google Scholar Articles by Boath, A. Articles by Bornancin, F. PubMed PubMed Citation Articles by Boath, A. Articles by Bornancin, F. Social Bookmarking                      What's this?

Regulation and Traffic of Ceramide 1-Phosphate Produced by Ceramide Kinase

COMPARATIVE ANALYSIS TO GLUCOSYLCERAMIDE AND SPHINGOMYELIN^*

From the Novartis Institutes for BioMedical Research, Vienna, Brunnerstrasse 59, A-1235 Wien, Austria

Ceramide 1-phosphate (C1P) has been characterized as a sphingolipid that participates in cell signaling. Although C1P synthesis is thought to occur via phosphorylation of ceramide by ceramide kinase (CerK), the processes that regulate C1P formation and fate remain largely unknown. In this study we analyzed bone marrow-derived macrophages (BMDM) from CerK-null mice (Cerk^-/-) and found significant levels of C1P, suggesting that previously unrecognized pathways may also lead to C1P formation. After these experiments we used an overexpression system, BMDM from Cerk^-/- mice, and short-chain fluorescent ceramides to trace CerK-dependent formation of C1P. Because the ceramide analogs can also be converted to glucosylceramide (GlcCer) and sphingomyelin (SM), they allowed us to directly compare all three metabolites. We found that C1P produced by CerK is turned over rapidly when serum is removed or upon calcium chelation, whereas GlcCer and SM are stable under these conditions. We further demonstrated that ceramide must be transported to the Golgi complex to be phosphorylated by CerK. Inhibition of the ceramide transfer protein slowed down SM formation without decreasing C1P, suggesting an alternate route of ceramide transport. Other experiments indicated that, like GlcCer and SM, C1P traffics along the secretory pathway to reach the plasma membrane. Furthermore, in BMDM C1P was secreted more readily than was GlcCer or SM. Altogether, our results indicate that CerK is essential to C1P formation via phosphorylation of Cer, providing the first insights into mechanisms underlying ceramide access to CerK and C1P trafficking as well as clarifying C1P as a signaling entity.

Received for publication, August 24, 2007 , and in revised form, December 7, 2007.

^* 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. 1–3.

¹ Supported by a fellowship from the European Commission Leonardo da Vinci program.

² To whom correspondence should be addressed. Tel.: 43-80166-335; Fax: 43-86634–582; E-mail: frederic.bornancin{at}novartis.com.

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