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Protein N‐glycosylation determines functionality of the Saccharomyces cerevisiae cell wall integrity sensor Mid2p
Author(s) -
Hutzler Franziska,
Gerstl Ronald,
Lommel Mark,
Strahl Sabine
Publication year - 2008
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2008.06243.x
Subject(s) - glycan , saccharomyces cerevisiae , biology , glycosylation , cell wall , mannose , biochemistry , microbiology and biotechnology , extracellular , cell membrane , membrane glycoproteins , n linked glycosylation , glycoprotein , cell , yeast
Summary The fungal cell wall is a highly dynamic structure that is essential to maintain cell shape and stability. Hence in yeasts and fungi cell wall integrity is tightly controlled. The Saccharomyces cerevisiae plasma membrane protein Mid2p is a putative mechanosensor that responds to cell wall stresses and morphological changes during pheromone induction. The extracellular domain of Mid2p, which is crucial to sensing, is highly O‐ and N‐glycosylated. We showed that O‐mannosylation is determining stability of Mid2p. If and how N‐glycosylation is linked to Mid2p function was unknown. Here we demonstrate that Mid2p contains a single high mannose N‐linked glycan at position Asn‐35. The N ‐glycan is located close to the N‐terminus and is exposed from the plasma membrane towards the cell wall through a highly O‐mannosylated domain that is predicted to adopt a rod‐like conformation. In contrast to O‐mannosylation, lack of the N‐linked glycan affects neither, stability of Mid2p nor distribution at the plasma membrane during vegetative and sexual growth. However, non‐N‐glycosylated Mid2p fails to perceive cell wall challenges. Our data further demonstrate that both the extent of the N‐linked glycan and its distance from the plasma membrane affect Mid2p function, suggesting the N ‐glycan to be directly involved in Mid2p sensing.