title: DES2 protein is responsible for phytoceramide biosynthesis in the mouse small intestine.
abstract: The C-4 hydroxylation of sphinganine and dihydroceramide is a rate-limiting reaction in the biosynthesis of phytosphingolipids. Mouse DES1 (MDES1) cDNA homologous to the Drosophila melanogaster degenerative spermatocyte gene-1 (des-1) cDNA leads to sphingosine Delta4-desaturase activity, and another mouse homologue, MDES2, has bifunctional activity, producing C-4 hydroxysphinganine and Delta4-sphingenine in yeast [Ternes, Franke, Zahringer, Sperling and Heinz (2002) J. Biol. Chem. 277, 25512-25518]. Here, we report the characterization of mouse DES2 (MDES2) using an in vitro assay with a homogenate of COS-7 cells transfected with MDES2 cDNA and N -octanoyl-sphinganine and sphinganine as substrates. MDES2 protein prefers dihydroceramide as a substrate to sphinganine, and exhibits dihydroceramide Delta4-desaturase and C-4 hydroxylase activities. MDES2 mRNA content was high in the small intestine and abundant in the kidney. In situ hybridization detected signals of MDES2 mRNA in the crypt cells. Immunohistochemistry using an anti-MDES2 peptide antibody stained the crypt cells and the adjacent epithelial cells. These results suggest that MDES2 is the dihydroceramide C-4 hydroxylase responsible for the biosynthesis of enriched phytosphingoglycolipids in the microvillous membranes of intestinal epithelial cells.
authors.affiliation: Sphingolipid Expression Laboratory, Frontier Research System, RIKEN, 2-1, Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: Fumio
authors.initials: F
authors.lastname: Omae
authors.forename: Masao
authors.initials: M
authors.lastname: Miyazaki
authors.forename: Ayako
authors.initials: A
authors.lastname: Enomoto
authors.forename: Minoru
authors.initials: M
authors.lastname: Suzuki
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Suzuki
authors.forename: Akemi
authors.initials: A
authors.lastname: Suzuki
mesh_terms: D000818:Animals; D019556:COS Cells; D002457:Cell Extracts; D002518:Ceramides / Q000096:biosynthesis* / Q000737:chemistry; D044943:Fatty Acid Desaturases / Q000235:genetics / Q000378:metabolism; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007421:Intestine, Small / Q000201:enzymology* / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D006899:Mixed Function Oxygenases / Q000235:genetics / Q000378:metabolism; D009097:Multienzyme Complexes / Q000235:genetics / Q000378:metabolism; D009928:Organ Specificity; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000378:metabolism; D014162:Transfection
chemical_list: D002457:Cell Extracts; D002518:Ceramides; D008565:Membrane Proteins; D009097:Multienzyme Complexes; C108139:N-octanoylsphinganine; D012333:RNA, Messenger; C109343:dihydroceramide; C489141:Degs2 protein, mouse; D006899:Mixed Function Oxygenases; D010088:Oxidoreductases; D044943:Fatty Acid Desaturases; C434953:delta-4 fatty acid desaturase; C108032:Degs protein, mouse; D013110:Sphingosine; C005682:safingol