Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
47
pubmed:dateCreated
2004-11-15
pubmed:databankReference
pubmed:abstractText
Sphingolipids are essential membrane components of eukaryotic cells. Their synthesis is initiated with the condensation of l-serine with palmitoyl-CoA, producing 3-ketodihydrosphingosine (KDS), followed by a reduction to dihydrosphingosine by KDS reductase. Until now, only yeast TSC10 has been identified as a KDS reductase gene. Here, we provide evidence that the human FVT-1 (hFVT-1) and mouse FVT-1 (mFVT-1) are functional mammalian KDS reductases. The forced expression of hFVT-1 or mFVT-1 in TSC10-null yeast cells suppressed growth defects, and hFVT-1 overproduced in cultured cells exhibited KDS reductase activity in vitro. Moreover, purified recombinant hFVT-1 protein exhibited NADPH-dependent KDS reductase activity. The identification of the FVT-1 genes enabled us to characterize the mammalian KDS reductase at the molecular level. Northern blot analyses demonstrated that both hFVT-1 and mFVT-1 mRNAs are ubiquitously expressed, suggesting that FVT-1 is a major KDS reductase. We also found the presence of hFVT-1 variants, which were differentially expressed among tissues. Immunofluorescence microscopic analysis revealed that hFVT-1 is localized at the endoplasmic reticulum. Moreover, a proteinase K digestion assay revealed that the large hydrophilic domain of hFVT-1, which contains putative active site residues, faces the cytosol. These results suggest that KDS is converted to dihydrosphingosine in the cytosolic side of the endoplasmic reticulum membrane. Moreover, the topology studies provide insight into the spatial organization of the sphingolipid biosynthetic pathway.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
19
pubmed:volume
279
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
49243-50
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:15328338-Alcohol Oxidoreductases, pubmed-meshheading:15328338-Amino Acid Sequence, pubmed-meshheading:15328338-Animals, pubmed-meshheading:15328338-Binding Sites, pubmed-meshheading:15328338-Blotting, Northern, pubmed-meshheading:15328338-COS Cells, pubmed-meshheading:15328338-Cell Line, pubmed-meshheading:15328338-Cell Proliferation, pubmed-meshheading:15328338-Cytosol, pubmed-meshheading:15328338-Endopeptidase K, pubmed-meshheading:15328338-Endoplasmic Reticulum, pubmed-meshheading:15328338-Escherichia coli, pubmed-meshheading:15328338-Gene Library, pubmed-meshheading:15328338-Genotype, pubmed-meshheading:15328338-HeLa Cells, pubmed-meshheading:15328338-Humans, pubmed-meshheading:15328338-Immunoblotting, pubmed-meshheading:15328338-Intracellular Membranes, pubmed-meshheading:15328338-Kinetics, pubmed-meshheading:15328338-Mice, pubmed-meshheading:15328338-Microscopy, Fluorescence, pubmed-meshheading:15328338-Models, Biological, pubmed-meshheading:15328338-Molecular Sequence Data, pubmed-meshheading:15328338-NADP, pubmed-meshheading:15328338-Protein Structure, Tertiary, pubmed-meshheading:15328338-RNA, Messenger, pubmed-meshheading:15328338-Recombinant Proteins, pubmed-meshheading:15328338-Sequence Homology, Amino Acid, pubmed-meshheading:15328338-Serine, pubmed-meshheading:15328338-Sphingolipids, pubmed-meshheading:15328338-Tissue Distribution, pubmed-meshheading:15328338-Transfection
pubmed:year
2004
pubmed:articleTitle
FVT-1 is a mammalian 3-ketodihydrosphingosine reductase with an active site that faces the cytosolic side of the endoplasmic reticulum membrane.
pubmed:affiliation
Department of Biomembrane and Biofunctional Chemistry, Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita 12-jo, Nishi 6-choume, Kita-ku, Sapporo 060-0812, Japan.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't