Cell wall synthesis specific cytocidal effect of Hansenula mrakii toxin-1 on Saccharomyces cerevisiae.
HM-1 toxin produced by Hansenula mrakii kills sensitive Saccharomyces cerevisiae. We found that the budding cells and the cells that responded to mating factor were sensitive to HM-1 toxin. These findings indicate that the target sites of HM-1 toxin are developing buds and conjugating tubes. The in vitro activity of beta-1,3-glucan synthase solubilized and partially purified from S. cerevisiae membranes was inhibited by HM-1 toxin at a concentration (around 50 nM, 0.5 micrograms/ml) that coincided well with its minimum inhibitory concentration for the growth of yeast cells. These data indicate that the HM-1 toxin perturbs the synthesis of yeast cell walls by inhibiting the glucan synthesis occurring at a budding site or a conjugating tube, which results in cell lysis.
Takasuka
T
T
Department of Molecular Genetics, Nippon Roche Research Center, Kamakura, Japan.
Komiyama
T
T
Furuichi
Y
Y
Watanabe
T
T
D002453:Cell Cycle; D002473:Cell Wall / Q000187:drug effects; D003513:Cycloheximide / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005936:Glucans / Q000096:biosynthesis; D005964:Glucosyltransferases / Q000037:antagonists & inhibitors / Q000378:metabolism; D055646:Killer Factors, Yeast; D008565:Membrane Proteins; D009183:Mycotoxins / Q000494:pharmacology*; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000187:drug effects*; D029702:Schizosaccharomyces pombe Proteins; D013997:Time Factors
D005936:Glucans; D055646:Killer Factors, Yeast; D008565:Membrane Proteins; D009183:Mycotoxins; D029702:Schizosaccharomyces pombe Proteins; D003513:Cycloheximide; D005964:Glucosyltransferases; C020570:1,3-beta-glucan synthase