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The SPTLC3 subunit of serine palmitoyltransferase generates short chain sphingoid bases


Hornemann, T; Penno, A; Rütti, M F; Ernst, D; Kivrak-Pfiffner, F; Rohrer, L; von Eckardstein, A (2009). The SPTLC3 subunit of serine palmitoyltransferase generates short chain sphingoid bases. Journal of Biological Chemistry, 284(39):26322-26330.

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.

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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Item Type:Journal Article, refereed, original work
Communities & Collections:04 Faculty of Medicine > University Hospital Zurich > Institute of Clinical Chemistry
Dewey Decimal Classification:610 Medicine & health
540 Chemistry
Language:English
Date:2009
Deposited On:30 Nov 2009 13:24
Last Modified:06 Dec 2017 22:01
Publisher:American Society for Biochemistry and Molecular Biology
ISSN:0021-9258
Additional Information:This research was originally published in Hornemann, T; Penno, A; Rütti, M F; Ernst, D; Kivrak-Pfiffner, F; Rohrer, L; von Eckardstein, A (2009). The SPTLC3 subunit of serine palmitoyltransferase generates short chain sphingoid bases. Journal of Biological Chemistry, 284(39):26322-26330. © the American Society for Biochemistry and Molecular Biology.
Free access at:PubMed ID. An embargo period may apply.
Publisher DOI:https://doi.org/10.1074/jbc.M109.023192
PubMed ID:19648650

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