Synthesis of monohydroxylated inositolphosphorylceramide (IPC-C) inSaccharomyces cerevisiae requires Scs7p, a protein with both a cytochrome b5-like domain and a hydroxylase/desaturase domain
✍ Scribed by Dunn, Teresa M.; Haak, Dale; Monaghan, Erin; Beeler, Troy J.
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 182 KB
- Volume
- 14
- Category
- Article
- ISSN
- 0749-503X
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✦ Synopsis
Saccharomyces cerevisiae mutants lacking Scs7p fail to accumulate the inositolphosphorylceramide (IPC) species, IPC-C, which is the predominant form found in wild-type cells. Instead scs7 mutants accumulate an IPC-B species believed to be unhydroxylated on the amide-linked C 26 -fatty acid. Elimination of the SCS7 gene suppresses the Ca 2+ -sensitive phenotype of csg1 and csg2 mutants. The CSG1 and CSG2 genes are required for mannosylation of IPC-C and accumulation of IPC-C by the csg mutants renders them Ca 2+ -sensitive. The SCS7 gene encodes a protein that contains both a cytochrome b 5 -like domain and a domain that resembles the family of cytochrome b 5 -dependent enzymes that use iron and oxygen to catalyse desaturation or hydroxylation of fatty acids and sterols. Scs7p is therefore likely to be the enzyme that hydroxylates the C 26 -fatty acid of IPC-C. 1998 John Wiley & Sons, Ltd.