RRC ID 889
Author Cortés JC, Katoh-Fukui R, Moto K, Ribas JC, Ishiguro J.
Title Schizosaccharomyces pombe Pmr1p is essential for cell wall integrity and is required for polarized cell growth and cytokinesis.
Journal Eukaryot Cell
Abstract The cps5-138 fission yeast mutant shows an abnormal lemon-like morphology at 28 degrees C in minimal medium and a lethal thermosensitive phenotype at 37 degrees C. Cell growth is completely inhibited at 28 degrees C in a Ca2+-free medium, in which the wild type is capable of growing normally. Under these conditions, actin patches become randomly distributed throughout the cell, and defects in septum formation and subsequent cytokinesis appear. The mutant cell is hypersensitive to the cell wall-digesting enzymatic complex Novozym234 even under permissive conditions. The gene SPBC31E1.02c, which complements all the mutant phenotypes described above, was cloned and codes for the Ca2+-ATPase homologue Pmr1p. The gene is not essential under optimal growth conditions but is required under conditions of low Ca2+ (<0.1 mM) or high temperature (>35 degrees C). The green fluorescent protein-tagged Cps5 proteins, which are expressed under physiological conditions (an integrated single copy with its own promoter in the cps5Delta strain), display a localization pattern typical of endoplasmic reticulum proteins. Biochemical analyses show that 1,3-beta-D-glucan synthase activity in the mutant is decreased to nearly half that of the wild type and that the mutant cell wall contains no detectable galactomannan when the cells are exposed to a Ca2+-free medium. The mutant acid phosphatase has an increased electrophoretic mobility, suggesting that incomplete protein glycosylation takes place in the mutant cells. These results indicate that S. pombe Pmr1p is essential for the maintenance of cell wall integrity and cytokinesis, possibly by allowing protein glycosylation and the polarized actin distribution to take place normally. Disruption and complementation analyses suggest that Pmr1p shares its function with a vacuolar Ca2+-ATPase homologue, Pmc1p (SPAPB2B4.04c), to prevent lethal activation of calcineurin for cell growth.
Volume 3(5)
Pages 1124-35
Published 2004-10-1
DOI 10.1128/EC.3.5.1124-1135.2004
PII 3/5/1124
PMID 15470240
PMC PMC522595
MeSH Actins / metabolism Base Sequence Calcium / metabolism Calcium-Transporting ATPases / genetics Calcium-Transporting ATPases / metabolism* Cell Division Cell Wall / metabolism Cytokinesis DNA, Fungal / genetics Galactose / analogs & derivatives Genes, Fungal Glucosyltransferases / metabolism Green Fluorescent Proteins / genetics Green Fluorescent Proteins / metabolism Hot Temperature Mannans / metabolism Mutation Phenotype Recombinant Fusion Proteins / genetics Recombinant Fusion Proteins / metabolism Schizosaccharomyces / genetics Schizosaccharomyces / growth & development* Schizosaccharomyces / metabolism* Schizosaccharomyces pombe Proteins / genetics Schizosaccharomyces pombe Proteins / metabolism*
IF 2.992
Times Cited 27
Yeast FY13839(CP13-8) FY7512(JY741) FY7499(JY746)