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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
11
pubmed:dateCreated
2000-4-12
pubmed:abstractText
Serine palmitoyltransferase catalyzes the first step of sphingolipid synthesis, condensation of serine and palmitoyl CoA to form the long chain base 3-ketosphinganine. The LCB1/TSC2 and LCB2/TSC1 genes encode homologous proteins of the alpha-oxoamine synthase family required for serine palmitoyltransferase activity. The other alpha-oxoamine synthases are soluble homodimers, but serine palmitoyltransferase is a membrane-associated enzyme composed of at least two subunits, Lcb1p and Lcb2p. Here, we report the characterization of a third gene, TSC3, required for optimal 3-ketosphinganine synthesis in Saccharomyces cerevisiae. S. cerevisiae cells lacking the TSC3 gene have a temperature-sensitive lethal phenotype that is reversed by supplying 3-ketosphinganine, dihydrosphingosine, or phytosphingosine in the growth medium. The tsc3 mutant cells have severely reduced serine palmitoyltransferase activity. The TSC3 gene encodes a novel 80-amino acid protein with a predominantly hydrophilic amino-terminal half and a hydrophobic carboxyl terminus that is membrane-associated. Tsc3p coimmunoprecipitates with Lcb1p and/or Lcb2p but does not bind as tightly as Lcb1p and Lcb2p bind to each other. Lcb1p and Lcb2p remain tightly associated with each other and localize to the membrane in cells lacking Tsc3p. However, Lcb2p is unstable in cells lacking Lcb1p and vice versa.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
17
pubmed:volume
275
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
7597-603
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed-meshheading:10713067-Acyltransferases, pubmed-meshheading:10713067-Adaptor Proteins, Signal Transducing, pubmed-meshheading:10713067-Amino Acid Sequence, pubmed-meshheading:10713067-Base Sequence, pubmed-meshheading:10713067-Carrier Proteins, pubmed-meshheading:10713067-Genes, Fungal, pubmed-meshheading:10713067-Hot Temperature, pubmed-meshheading:10713067-Membrane Proteins, pubmed-meshheading:10713067-Microsomes, pubmed-meshheading:10713067-Molecular Sequence Data, pubmed-meshheading:10713067-Mutation, pubmed-meshheading:10713067-Precipitin Tests, pubmed-meshheading:10713067-Protein Binding, pubmed-meshheading:10713067-Saccharomyces cerevisiae, pubmed-meshheading:10713067-Saccharomyces cerevisiae Proteins, pubmed-meshheading:10713067-Serine C-Palmitoyltransferase, pubmed-meshheading:10713067-Sphingosine, pubmed-meshheading:10713067-Suppression, Genetic
pubmed:year
2000
pubmed:articleTitle
Tsc3p is an 80-amino acid protein associated with serine palmitoyltransferase and required for optimal enzyme activity.
pubmed:affiliation
Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't