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Synthesis of monohydroxylated inositolphosphorylceramide (IPC‐C) in Saccharomyces cerevisiae requires Scs7p, a protein with both a cytochrome b 5 ‐like domain and a hydroxylase/desaturase domain
Author(s) -
Dunn Teresa M.,
Haak Dale,
Monaghan Erin,
Beeler Troy J.
Publication year - 1998
Publication title -
yeast
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.923
H-Index - 102
eISSN - 1097-0061
pISSN - 0749-503X
DOI - 10.1002/(sici)1097-0061(19980315)14:4<311::aid-yea220>3.0.co;2-b
Subject(s) - cytochrome b5 , mutant , biology , biochemistry , hydroxylation , saccharomyces cerevisiae , enzyme , cytochrome , cytochrome p450 , gene , fatty acid , fatty acid desaturase , phenotype , polyunsaturated fatty acid
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.