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Mannosylinositol phosphorylceramides and ergosterol coodinately maintain cell wall integrity in the yeast Saccharomyces cerevisiae
Author(s) -
Tanaka Seiya,
Tani Motohiro
Publication year - 2018
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/febs.14509
Subject(s) - ergosterol , saccharomyces cerevisiae , yeast , biology , structural integrity , chemistry , microbiology and biotechnology , biochemistry , engineering , structural engineering
In the yeast Saccharomyces cerevisiae , complex sphingolipids have three types of polar head group, and breakdown of their normal composition causes several cellular dysfunctions. Previously we found that loss of biosynthesis of mannosylinositol phosphorylceramide ( MIPC ) causes a defect in cell wall integrity (CWI). In this study, we screened for multicopy suppressor genes that rescue the defect in CWI in cells lacking MIPC synthases (Sur1 and Csh1), and found that the defect is partly suppressed by upregulation of ergosterol biosynthesis. In addition, repression of expression of ERG 9 , which encodes squalene synthase in the ergosterol biosynthesis pathway, in sur1∆ csh1∆ cells caused a strong growth defect and enhancement of the defect in CWI. The repression of ERG 9 and/or the deletion of SUR 1 and CSH 1 caused an increase in the phosphorylated form of Slt2, a mitogen‐activated protein kinase activated through impairment of CWI. Moreover, the deletion of SLT 2 or WSC 1/2 , encoding a sensor protein recognizing CWI, enhanced the growth defect in the ERG 9 ‐repressed sur1∆ csh1∆ cells. On the other hand, the ERG 9 ‐repressed sur1∆ csh1∆ cells also exhibited an increase in the cell wall chitin level in a Slt2‐ and Wsc1/2‐independent manner. These results suggested that MIPC and ergosterol are coordinately involved in maintenance of CWI, and the activation of Slt2 suppressed the CWI defect caused by these metabolic defects.