The Acyl-CoA Synthetases Encoded within FAA1 andFAA4 in Saccharomyces cerevisiaeFunction as Components of the Fatty Acid Transport System Linking Import, Activation, and Intracellular Utilization

Abstract

Exogenous long-chain fatty acids are activated to coenzyme A derivatives prior to metabolic utilization. In the yeast Saccharomyces cerevisiae, the activation of these compounds prior to metabolic utilization proceeds through the fatty acyl-CoA synthetases Faa1p and Faa4p. Faa1p or Faa4p are essential for long-chain fatty acid import, suggesting that one or both of these enzymes are components of the fatty acid transport system, which also includes Fat1p. By monitoring the intracellular accumulation of the fluorescent long-chain fatty acid analogue 4,4-difluoro-5-methyl-4-bora-3a,4a-diazas-indacene-3-dodecanoic acid, long-chain fatty acid transport was shown to be severely restricted in a faa1⌬ faa4⌬ strain. These data established for the first time a mechanistic linkage between the import and activation of exogenous fatty acids in yeast. To investigate this linkage further, oleoyl CoA levels were defined following incubation of wild type and mutant cells with limiting concentrations of exogenous oleate. These studies demonstrated oleoyl CoA levels were reduced to less than 10% wild-type levels in faa1⌬ and faa1⌬ faa4⌬ strains. Defects in metabolic utilization and intracellular trafficking were also found in the fatty acyl-CoA synthetase-deficient strains. The faa1⌬ faa4⌬ strain had a marked reduction in endogenous acyl-CoA pools, suggesting these enzymes play a role in maintenance of endogenous acyl-CoA pools, metabolism and trafficking. In addition, this strain had levels of in vivo ␤-oxidation of exogenous oleate reduced 3-fold when compared with the isogenic parent. Northern analyses demonstrated an additional defect in fatty acid trafficking as FAA1 or FAA4 were required for the transcriptional regulation of the genes encoding the peroxisomal enzymes acylCoA oxidase (POX1) and medium-chain acyl-CoA synthetase (FAA2). These data support the hypothesis that fatty acyl-CoA synthetase (Faa1p or Faa4p) functions as a component of the fatty acid import system by linking import and activation of exogenous fatty acids to intracellular utilization and signaling.

Fatty Acid Transport in Saccharomyces cerevisiae

“…In the yeast Saccharomyces cerevisiae, fatty acid transport across the membrane is complex and emulates the conditions present in mammalian cells. Work from our laboratory and others is consistent with the hypothesis that several distinct proteins are involved in regulated fatty acid import, activation, and subsequent intracellular trafficking (29,(33)(34)(35). The principal players in this process include the membrane-bound protein Fat1p, the yeast orthologue of murine FATP, and longchain fatty acyl-CoA synthetase (primarily Faa1p).…”

“…The principal players in this process include the membrane-bound protein Fat1p, the yeast orthologue of murine FATP, and longchain fatty acyl-CoA synthetase (primarily Faa1p). Emerging evidence suggests that Fat1p and Faa1p work in concert and are each required for fatty acid import and targeting to specific intracellular pools and organelles (29). Yeast strains containing a deletion in the structural gene for Fat1p (fat1⌬) are distinct from the wild type cells on the basis of a number of growth and biochemical phenotypes (29,33,34).…”

Fungi and animals may share a common ancestor to nuclear receptors

“…2C). The ⌬faa1͞⌬faa4 double-mutant strain is defective in fatty acid uptake and activation to CoA derivatives, the first enzymatic step toward metabolism, because it lacks the two main acyl-CoA synthetases for C12-C18 fatty acids (27,28). It is conceivable that the levels of endogenously synthesized oleate in these mutant cells are elevated because they are trying to cope with their inability to take up fatty acids.…”

Dosage-dependent functions of fatty acid desaturase Ole1p in growth and morphogenesis of Candida albicans

“…In addition, the low oxygen response promoter element (LORE) mediates oxygen repression of OLE1 (Nakagawa et al, 2001;Vasconcelles et al, 2001). Two genes encoding components of fatty acid transporters, FAA1 and FAA4, were found to be essential for unsaturated fatty acidrepression of OLE1 via FAR sequences (Faergeman et al, 2001). Also, the acyl-CoA binding protein and the Ssn6-Tup1 complex were shown to be involved in repression of OLE1 (Fujimori et al, 1997).…”