The SPTLC3 subunit of serine palmitoyltransferase generates short chain sphingoid bases.
J Biol Chem
; 284(39): 26322-30, 2009 Sep 25.
Article
em En
| MEDLINE
| ID: mdl-19648650
ABSTRACT
The enzyme serine palmitoyltransferase (SPT) catalyzes the rate-limiting step in the de novo synthesis of sphingolipids. Previously the mammalian SPT was described as a heterodimer composed of two subunits, SPTLC1 and SPTLC2. Recently we identified a novel third SPT subunit (SPTLC3). SPTLC3 shows about 68% identity to SPTLC2 and also includes a pyridoxal phosphate consensus motif. Here we report that the overexpression of SPTLC3 in HEK293 cells leads to the formation of two new sphingoid base metabolites, namely C(16)-sphinganine and C(16)-sphingosine. SPTLC3-expressing cells have higher in vitro SPT activities with lauryl- and myristoyl-CoA than SPTLC2-expressing cells, and SPTLC3 mRNA expression levels correlate closely with the C(16)-sphinganine synthesis rates in various human and murine cell lines. Approximately 15% of the total sphingolipids in human plasma contain a C(16) backbone and are found in the high density and low density but not the very low density lipoprotein fraction. In conclusion, we show that the SPTLC3 subunit generates C(16)-sphingoid bases and that sphingolipids with a C(16) backbone constitute a significant proportion of human plasma sphingolipids.
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Base de dados:
MEDLINE
Assunto principal:
Esfingolipídeos
/
Serina C-Palmitoiltransferase
Limite:
Humans
Idioma:
En
Revista:
J Biol Chem
Ano de publicação:
2009
Tipo de documento:
Article
País de afiliação:
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