The fission yeast SEL1 domain protein Cfh3p: a novel regulator of the glucan synthase Bgs1p whose function is more relevant under stress conditions.
In Schizosaccharomyces pombe, Bgs1/Cps1p is a beta(1,3)-glucan synthase required for linear beta(1,3)-glucan synthesis and primary septum formation. Here, we have studied the regulation of Bgs1p by Cfh3/Chr4p, a member of a family of conserved adaptor proteins, which resembles the chitin synthase regulator Chs4p from Saccharomyces cerevisiae and Candida albicans. cfh3Delta cells showed a genetic interaction with cps1-191, and Cfh3p co-immunoprecipitated with Bgs1/Cps1p. In the absence of cfh3(+), cells were more sensitive to digestion by glucanases, and both Calcofluor staining and glucan synthesis were reduced. We found that in a wild-type strain, beta(1,3)-glucan synthesis was reduced under stress conditions. In the cfh3Delta, cps1-191, and cfh3Delta cps1-191 strains, beta(1,3)-glucan synthesis was further reduced, and growth was impaired under stress conditions, suggesting that Cfh3p and Bgs1p might play a role in ensuring growth in unfavorable environments. In a cfh3Delta mutant, Bgs1p was delocalized when the cells were distressed, but a blockade in endocytosis prevented this delocalization. Finally, we found that the SEL1 repeats are required for Cfh3p function. These results show that Cfh3p is a regulatory protein for Bgs1p and that its function is particularly necessary when the cells are undergoing stress.
Sharifmoghadam
Mohammad Reza
MR
Departamento de Microbiología y Genética/Instituto de Microbiología Bioquímica, Universidad de Salamanca/CSIC, 37007 Salamanca, Spain.
Valdivieso
M-Henar
MH
D001557:Benzenesulfonates / Q000737:chemistry; D002352:Carrier Proteins / Q000378:metabolism*; D002473:Cell Wall / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D005964:Glucosyltransferases / Q000737:chemistry* / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000378:metabolism; D009154:Mutation; D010641:Phenotype; D017434:Protein Structure, Tertiary; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D012568:Schizosaccharomyces / Q000378:metabolism* / Q000502:physiology*; D029702:Schizosaccharomyces pombe Proteins / Q000096:biosynthesis / Q000378:metabolism / Q000502:physiology*; D015398:Signal Transduction; D013997:Time Factors
D001557:Benzenesulfonates; D002352:Carrier Proteins; C541035:Cfh3 protein, S pombe; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; C507001:UBX2 protein, S cerevisiae; D049452:Green Fluorescent Proteins; C007061:C.I. Fluorescent Brightening Agent 28; D005964:Glucosyltransferases; C040232:glucan synthase; C020570:1,3-beta-glucan synthase