Identification of a putative alpha-glucan synthase essential for cell wall construction and morphogenesis in fission yeast.
The cell wall protects fungi against lysis and determines their cell shape. Alpha-glucan is a major carbohydrate component of the fungal cell wall, but its function is unknown and its synthase has remained elusive. Here, we describe a fission yeast gene, ags1(+), which encodes a putative alpha-glucan synthase. In contrast to the structure of other carbohydrate polymer synthases, the predicted Ags1 protein consists of two probable catalytic domains for alpha-glucan assembly, namely an intracellular domain for alpha-glucan synthesis and an extracellular domain speculated to cross-link or remodel alpha-glucan. In addition, the predicted Ags1 protein contains a multipass transmembrane domain that might contribute to transport of alpha-glucan across the membrane. Loss of Ags1p function in a temperature-sensitive mutant results in cell lysis, whereas mutant cells grown at the semipermissive temperature contain decreased levels of cell wall alpha-glucan and fail to maintain rod shapes, causing rounding of the cells. These findings demonstrate that alpha-glucan is essential for fission yeast morphogenesis.
Cell Biology and Metabolism Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA. hochstenbach@bio.uva.nl
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F
Hochstenbach
F M
FM
Klis
H
H
van den Ende
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E
van Donselaar
P J
PJ
Peters
R D
RD
Klausner
D000595:Amino Acid Sequence; D002473:Cell Wall; D003001:Cloning, Molecular; D005964:Glucosyltransferases / Q000235:genetics / Q000378:metabolism*; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D012568:Schizosaccharomyces / Q000166:cytology / Q000201:enzymology* / Q000648:ultrastructure; D029702:Schizosaccharomyces pombe Proteins; D017386:Sequence Homology, Amino Acid
D029702:Schizosaccharomyces pombe Proteins; D005964:Glucosyltransferases; C114021:ags1 protein, S pombe