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

J. Biol. Chem., Vol. 280, Issue 44, 36592-36600, November 4, 2005

This Article Full Text Full Text (PDF) All Versions of this Article: 280/44/36592    most recent M506827200v1 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 Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Tani, M. Articles by Ito, M. Search for Related Content PubMed PubMed Citation Articles by Tani, M. Articles by Ito, M. Social Bookmarking                      What's this?

Involvement of Neutral Ceramidase in Ceramide Metabolism at the Plasma Membrane and in Extracellular Milieu^*

Motohiro Tani, Yasuyuki Igarashi, and Makoto Ito1

From the Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan and the Department of Biomembrane and Biofunctional Chemistry, Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita 12. Nishi 6, Kita-ku, Sapporo 060-0812, Japan

Neutral ceramidase is a type II integral membrane protein, which is occasionally secreted into the extracellular milieu after the processing of its N-terminal anchor (Tani, M., Iida, H., and Ito, M. (2003) J. Biol. Chem. 278, 10523–10530). We found that when overexpressed in CHOP cells, neutral ceramidase hydrolyzed cell surface ceramide, which increased in amount after the treatment of cells with bacterial sphingomyelinase, leading to an increase in the cellular level of sphingosine and sphingosine 1-phosphate. On the other hand, knockdown of the endogenous enzyme by siRNA decreased the cellular level of both sphingolipid metabolites. The treatment of cells with bovine serum albumin significantly reduced the cellular level of sphingosine, but not sphingosine 1-phosphate, generated by overexpression of the enzyme. The cellular level of sphingosine 1-phosphate increased with overexpression of the cytosolic sphingosine kinase. These results suggest that sphingosine 1-phosphate is mainly produced inside of the cell after the incorporation of sphingosine generated on the plasma membranes. The enzyme also seems to participate in the hydrolysis of serum-derived ceramide in the vascular system. Significant amounts of sphingosine as well as sphingosine 1-phosphate were generated in the cell-free conditioned medium of ceramidase transfectants, compared with mock transfectants. No increase in these metabolites was observed if serum or bacterial sphingomyelinase was omitted from the conditioned medium, suggesting that the major source of ceramide is the serum-derived sphingomyelin. A sphingosine 1-phosphate receptor, S1P₁, was internalized much faster by the treatment of S1P₁-overexpressing cells with conditioned medium of ceramidase transfectants than that of mock transfectants. Collectively, these results clearly indicate that the enzyme is involved in the metabolism of ceramide at the plasma membrane and in the extracellular milieu, which could regulate sphingosine 1-phosphate-mediated signaling through the generation of sphingosine.

Received for publication, June 23, 2005 , and in revised form, August 23, 2005.

^* This work was supported in part by Grants-in-aid for Scientific Research on Priority Areas (B) (12140204 (to M. I.) and 12140201 (to Y. I.)), and Basic Research (B) (17380068 (to M. I.)) from the Ministry of Education, Culture, Sports, Science and Technology, the Japanese Government. 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.

¹ To whom correspondence should be addressed: Dept. of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan. Tel.: 81-92-642-2898; Fax: 81-92-642-2907; E-mail: makotoi{at}agr.kyushu-u.ac.jp.

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

This article has been cited by other articles:

				A. Kontush, P. Therond, A. Zerrad, M. Couturier, A. Negre-Salvayre, J. A. de Souza, S. Chantepie, and M. J. Chapman Preferential Sphingosine-1-Phosphate Enrichment and Sphingomyelin Depletion Are Key Features of Small Dense HDL3 Particles: Relevance to Antiapoptotic and Antioxidative Activities Arterioscler. Thromb. Vasc. Biol., August 1, 2007; 27(8): 1843 - 1849. [Abstract] [Full Text] [PDF]

				E. Tellier, A. Negre-Salvayre, B. Bocquet, S. Itohara, Y. A. Hannun, R. Salvayre, and N. Auge Role for Furin in Tumor Necrosis Factor Alpha-Induced Activation of the Matrix Metalloproteinase/Sphingolipid Mitogenic Pathway Mol. Cell. Biol., April 15, 2007; 27(8): 2997 - 3007. [Abstract] [Full Text] [PDF]

				N. Okino and M. Ito Ceramidase Enhances Phospholipase C-induced Hemolysis by Pseudomonas aeruginosa J. Biol. Chem., March 2, 2007; 282(9): 6021 - 6030. [Abstract] [Full Text] [PDF]

				R. Xu, J. Jin, W. Hu, W. Sun, J. Bielawski, Z. Szulc, T. Taha, L. M. Obeid, and C. Mao Golgi alkaline ceramidase regulates cell proliferation and survival by controlling levels of sphingosine and S1P FASEB J, September 1, 2006; 20(11): 1813 - 1825. [Abstract] [Full Text] [PDF]