Hydroxylation of Saccharomyces cerevisiae Ceramides Requires Sur2p and Scs7p

Abstract

The Saccharomyces cerevisiae SCS7 and SUR2 genes are members of a gene family that encodes enzymes that desaturate or hydroxylate lipids. Sur2p is required for the hydroxylation of C-4 of the sphingoid moiety of ceramide, and Scs7p is required for the hydroxylation of the very long chain fatty acid. Neither SCS7 nor SUR2 are essential for growth, and lack of the Scs7p-or Sur2p-dependent hydroxylation does not prevent the synthesis of mannosyldiinositolphosphorylceramide, the mature sphingolipid found in yeast. Deletion of either gene suppresses the Ca 2؉ -sensitive phenotype of csg2⌬ mutants, which arises from overaccumulation of inositolphosphorylceramide due to a defect in sphingolipid mannosylation. Characterization of scs7 and sur2 mutants is expected to provide insight into the function of ceramide hydroxylation.

Alteration of complex sphingolipid composition and its physiological significance in yeast Saccharomyces cerevisiae lacking vacuolar ATPase

“…The A-type contains dihydrosphingosine (DHS) and very long-chain fatty acids, which are mostly of 26-carbon chain length. The hydroxylation patterns of the B-, B'-and C-types are determined by two hydroxylases, Sur2 and Scs7, which catalyse hydroxylation at the C-4 position of the DHS and the C-2 position of the very long-chain fatty acids, respectively (Haak et al, 1997). The D-type is generated on further hydroxylation at an unknown position of the fatty acid moiety of the C type, and CCC2 encoding a copper transporter is required for the synthesis .…”

A new class of lipid desaturase central to sphingolipid biosynthesis and signalling

“…Second, the ∆ 4 -LCB desaturase also shows no sequence similarity to the S. cerevisiae Sur2p, which synthesizes phytosphingosine by the C4 hydroxylation of dihydrosphingosine (Fig. 1) [11]. Because these two enzymes share the same regiospecificity and substrate, they might be predicted to display a paralogous relationship; but this is not the case.…”

“…This led them to propose a revised model that not only had a greater degree of resemblance to other di-iron enzymes but also, importantly, considered the oxidase to be an interfacial rather than a transmembrane protein [5,10]. Recent site-directed mutagenesis experiments on plant [11] and trypanosomal alternative oxidases [12] are generally supportive of such a structure, although they do question the extent to which the primary coordination sphere of the di-iron centre is universally conserved and hence raise the possibility of species-specific variations [8].…”

Sphingolipid C4 hydroxylation influences properties of yeast detergent‐insoluble glycolipid‐enriched membranes

“…The gene responsible for sphingoid base C4 hydroxylation in S. cerevisiae has been identified and studied [2][3][4]. It was recognized as SUR2 [2], but also as SYR2 [5], since it is necessary for the antifungal action of syringomycin E, a small lipodepsinonapeptide secreted by the bacterium Pseudomonas syringae.…”

“…It was recognized as SUR2 [2], but also as SYR2 [5], since it is necessary for the antifungal action of syringomycin E, a small lipodepsinonapeptide secreted by the bacterium Pseudomonas syringae.…”