Loss of the plasma membrane-bound protein Gas1p in Saccharomyces cerevisiae results in the release of beta1,3-glucan into the medium and induces a compensation mechanism to ensure cell wall integrity.
Deletion of GAS1/GGP1/CWH52 results in a lower beta-glucan content of the cell wall and swollen, more spherical cells (L. Popolo, M. Vai, E. Gatti, S. Porello, P. Bonfante, R. Balestrini, and L. Alberghina, J. Bacteriol. 175:1879-1885, 1993; A. F. J. Ram, S. S. C. Brekelmans, L. J. W. M. Oehlen, and F. M. Klis, FEBS Lett. 358:165-170, 1995). We show here that gas1delta cells release beta1,3-glucan into the medium. Western analysis of the medium proteins with beta1,3-glucan- and beta1,6-glucan-specific antibodies showed further that at least some of the released beta1,3-glucan was linked to protein as part of a beta1,3-glucan-beta1,6-glucan-protein complex. These data indicate that Gas1p might play a role in the retention of beta1,3-glucan and/or beta-glucosylated proteins. Interestingly, the defective incorporation of beta1,3-glucan in the cell wall was accompanied by an increase in chitin and mannan content in the cell wall, an enhanced expression of cell wall protein 1 (Cwp1p), and an increase in beta1,3-glucan synthase activity, probably caused by the induced expression of Fks2p. It is proposed that the cell wall weakening caused by the loss of Gas1p induces a set of compensatory reactions to ensure cell integrity.
Ram
A F
AF
Institute of Molecular Cell Biology, BioCentrum Amsterdam, University of Amsterdam, The Netherlands.
Kapteyn
J C
JC
Montijn
R C
RC
Caro
L H
LH
Douwes
J E
JE
Baginsky
W
W
Mazur
P
P
van den Ende
H
H
Klis
F M
FM
D015153:Blotting, Western; D050260:Carbohydrate Metabolism; D002241:Carbohydrates / Q000032:analysis; D002473:Cell Wall / Q000737:chemistry / Q000378:metabolism; D002686:Chitin / Q000378:metabolism; D003001:Cloning, Molecular; D017077:Culture Media, Conditioned / Q000032:analysis; D004271:DNA, Fungal / Q000235:genetics / Q000302:isolation & purification; D005656:Fungal Proteins / Q000032:analysis / Q000378:metabolism; D015870:Gene Expression; D005936:Glucans / Q000276:immunology / Q000378:metabolism*; D005964:Glucosyltransferases; D006023:Glycoproteins / Q000378:metabolism; D008351:Mannans / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000235:genetics* / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism; D010957:Plasmids; D016133:Polymerase Chain Reaction; D012331:RNA, Fungal / Q000032:analysis; D011995:Recombination, Genetic; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D017384:Sequence Deletion; D047071:beta-Glucans
C093810:CWP1 protein, S cerevisiae; D002241:Carbohydrates; D017077:Culture Media, Conditioned; D004271:DNA, Fungal; D005656:Fungal Proteins; C066709:GAS1 protein, S cerevisiae; D005936:Glucans; D006023:Glycoproteins; D008351:Mannans; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D012331:RNA, Fungal; D029701:Saccharomyces cerevisiae Proteins; D047071:beta-Glucans; D002686:Chitin; C064197:beta-1,6-glucan; C033363:beta-1,3-glucan; D005964:Glucosyltransferases; C095724:GSC2 protein, S cerevisiae