Carnitine-dependent metabolic activities in Saccharomyces cerevisiae

Three carnitine acetyltransferases are essential in a carnitine-dependent strain

Jan H. Swiegers, Nola Dippenaar, Isak S. Pretorius, Florian F. Bauer*

*Corresponding author for this work

Research output: Contribution to journalArticle

62 Citations (Scopus)

Abstract

L-Carnitine is required for the transfer of activated acyl-groups across intracellular membranes in eukaryotic organisms. In Saccharomyces cerevisiae, peroxisomal membranes are impermeable to acetyl-CoA, which is produced in the peroxisome when cells are grown on fatty acids as carbon source. In a reversible reaction catalysed by carnitine acetyltransferases (CATs), activated acetyl groups are transferred to carnitine to form acetylcarnitine which can be shuttled across membranes. Here we describe a mutant selection strategy that specifically selects for mutants affected in carnitine-dependent metabolic activities. Complementation of three of these mutants resulted in the cloning of three CAT encoding genes: CAT2, coding for the carnitine acetyltransferase associated with the peroxisomes and the mitochondria; YAT1, coding for the carnitine acetyltransferase, which is presumably associated with the outer mitochondrial membrane, and YER024w (YAT2), which encodes a third, previously unidentified carnitine acetyltransferase. The data also show that (a) L-carnitine and all three CATs are essential for growth on non-fermentable carbon sources in a strain with a disrupted CIT2 gene; (b) Yat2p contributes significantly to total CAT activity when cells are grown on ethanol; and that (c) the carnitine-dependent transfer of activated acetyl groups plays a more important role in cellular processes than previously realised.

Original languageEnglish
Pages (from-to)585-595
Number of pages11
JournalYeast
Volume18
Issue number7
DOIs
Publication statusPublished - 2001
Externally publishedYes

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