Open AccessLocalized deposition of chitin on the yeast cell surface in response to mating pheromone
Author(s) -
Randy Schekman,
Vicki Brawley
Publication year - 1979
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.76.2.645
Subject(s) - chitin , chitin synthase , biochemistry , biology , mating type , intracellular , zymogen , cell wall , budding , enzyme , microbiology and biotechnology , chitosan , gene
Treatment ofa mating-typeSaccharomyces cerevisiae cells with the pheromone α-factor (secreted by α mating-type cells) induces the synthesis of chitin. Small daughter cells, which start with no detectable chitin, make 3 times more chitin when grown in the presence of α-factor than do untreated exponentially growing cells. Budding cells accumulate chitin in the nascent division septum [Cabib, E. & Bowers, B. (1975)J. Bacteriol . 124, 1586), as detected by staining with the fluorescent dye primulin. In the absence of a division septum, α-factor-treated cells accumulate chitin in the area of pheromone-stimulated growth. Enzymatic lysis of budding and pheromone-treated cells allows the separation of membrane-bound chitin synthase (UDP-2-acetamido-2-deoxy-D-glucose: chitin 4-β-acetamidodeoxyglucosyltransferase, EC 2.4.1.16) activity from a dense particulate fraction containing chitin. Chitin synthase activity is associated with both the plasma membrane and small intracellular particles. During pheromone treatment, the levels of chitin synthase in the plasma membrane and in intracellular particle fractions increase 11- and 4-fold, respectively. Although chitin synthase is made as zymogen that requires proteolytic activation, the plasma membrane of pheromone-treated cells shows a significant fraction of preactivated enzyme; intracellular membrane-bound synthase is found exclusively in the zymogen form.