The Saccharomyces cerevisiae Peroxisomal 2,4-Dienoyl-CoA Reductase Is Encoded by the Oleate-inducible GeneSPS19

Abstract

␤-Oxidation is compartmentalized in mammals into both mitochondria and peroxisomes. Fatty acids with double bonds at even-numbered positions require for their degradation the auxiliary enzyme 2,4-dienoyl-CoA reductase, and at least three isoforms, two mitochondrial and one peroxisomal, exist in the rat. The Saccharomyces cerevisiae Sps19p is 34% similar to the human and rat mitochondrial reductases, and an SPS19 deleted strain was unable to utilize petroselineate (cis-C 18:1(6) ) as the sole carbon source, but remained viable on oleate (cis-C 18:1(9) ). Sps19p was purified to homogeneity from oleate-induced cells and the homodimeric enzyme (native molecular weight 69,000) converted 2,4-hexadienoyl-CoA into 3-hexenoyl-CoA in an NADPH-dependent manner and therefore contained 2,4-dienoyl-CoA reductase activity. Antibodies raised against Sps19p decorated the peroxisomal matrix of oleate-induced cells. SPS19 shares with the sporulation-specific SPS18 a common promoter region that contains an oleate response element. This element unidirectionally regulates transcription of the reductase and is sufficient for oleate induction of a promoterless CYC1-lacZ reporter gene. SPS19 is dispensable for growth and sporulation on solid acetate and oleate media, but is essential for these processes to occur on petroselineate.

Dynamics of Gene Expression Revealed by Comparison of Serial Analysis of Gene Expression Transcript Profiles from Yeast Grown on Two Different Carbon Sources

“…To degrade polyunsaturated fatty acids, double bonds at even positions must be relocated to uneven positions in a reductive process requiring NADPH (Gurvitz et al, 1997). The induction on oleate of the genes encoding peroxisomal and cytosolic isocitrate dehydrogenase (IDP3 and IDP2, respectively) sug- Ninety-five percent confidence intervals (thin lines) for the number of copies per cell found in the oleate condition (thick line) and critical values for the statistical comparison of these numbers with numbers found in a control condition.…”

“…NADPH in the peroxisomal matrix, to enable the action of the peroxisomal 2,4 dienoyl-CoA reductase Sps19p, which is required for degradation of unsaturated fatty acids with double bonds at even positions (Gurvitz et al, 1997;Henke et al, 1998;van Roermund et al, 1998). The existence of an isocitrate/2-oxoglutarate redox shuttle across the peroxisomal membrane (Figure 4) is indicated by the tandem induction of both the IDP3 gene (20 c/c on oleate, Ͻ0.3 c/c on glucose) and the IDP2 gene (29 c/c on oleate, Ͻ0.3 c/c on glucose) encoding peroxisomal isocitrate dehydrogenase Idp3p and cytosolic isocitrate dehydrogenase Idp2p, respectively.…”

Molecular Characterization of Saccharomyces cerevisiae Δ3,Δ2-Enoyl-CoA Isomerase

“…Of these auxiliary enzymes, only the 2,4-dienoyl-CoA reductase (SPS19) (16) and the NADP ϩ -dependent isocitrate dehydrogenase (IDP3) (12,13) have been described in yeast, leaving the ⌬ 3 ,⌬ 2 -enoyl-CoA isomerase and the ⌬ 3,5 ,⌬ 2,4 -dienoyl-CoA isomerase to be identified. We recently scanned the S. cerevisiae genome for genes encoding putative peroxisomal proteins carrying a type 1 or 2 peroxisomal targeting signal (PTS-1 1 (17) or PTS-2 (18)) and for genes containing a putative oleate response element (ORE) (19) in their promoters.…”

Characterization of PECI, a Novel Monofunctional Δ3,Δ2-Enoyl-CoA Isomerase of Mammalian Peroxisomes

“…Although these enzymes are necessary for all fatty acid ␤-oxidation, the complete metabolism of unsaturated fatty acids requires one or more additional auxiliary enzymes (6). These include ⌬ 3 ,⌬ 2 -enoylCoA isomerase (Eci1p) (7,8), a 2,4-dienoyl-CoA reductase (Sps19p) (9), an NADP ϩ -dependent isocitrate dehydrogenase (Idp3p) (10,11), and a ⌬ 3,5 ,⌬ 2,4 -dienoyl-CoA isomerase (although this enzyme has yet to be identified in yeast). Among these auxiliary enzymes, ⌬ 3 ,⌬ 2 -enoyl-CoA isomerase (Eci1p) is unique in that its activity is essential for the ␤-oxidation of all unsaturated fatty acids ( Fig.…”