The β-1,6-glucan containing side-chain of cell wall proteins of Saccharomyces cerevisiae is bound to the glycan core of the GPI moiety

Vaart, J Van Der

doi:10.1016/s0378-1097(96)00440-5

Cited by 35 publications

(22 citation statements)

References 10 publications

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“…This was confirmed here, as 98% of all SDS-resistant proteins in the cell wall could be solubilized by ␤1,3-glucanase digestion of the cell wall ( Table 1). The linkage between these proteins and ␤1,6-glucan was reported to be of the phosphodiester type (18), which is in line with other studies providing evidence for a GPI-derived structure as an attachment site for ␤1,6-glucan (3,23,40,42,45). There are conflicting data concerning the exact structure of the GPI remnant of mature incorporated cell wall proteins.…”

Section: Discussionsupporting

confidence: 84%

Altered extent of cross-linking of beta1,6-glucosylated mannoproteins to chitin in Saccharomyces cerevisiae mutants with reduced cell wall beta1,3-glucan content

et al. 1997

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The yeast cell wall contains ␤1,3-glucanase-extractable and ␤1,3-glucanase-resistant mannoproteins. The ␤1,3-glucanase-extractable proteins are retained in the cell wall by attachment to a ␤1,6-glucan moiety, which in its turn is linked to ␤1,3-glucan (J. C. Kapteyn, R. C. Montijn, E. Vink, J. De La Cruz, A. Llobell, J. E. Douwes, H. Shimoi, P. N. Lipke, and F. M. Klis, Glycobiology 6:337-345, 1996). The ␤1,3-glucanase-resistant protein fraction could be largely released by exochitinase treatment and contained the same set of ␤1,6-glucosylated proteins, including Cwp1p, as the ␤1,3-glucanase-extractable fraction. Chitin was linked to the proteins in the ␤1,3-glucanase-resistant fraction through a ␤1,6-glucan moiety. In wild-type cell walls, the ␤1,3-glucanase-resistant protein fraction represented only 1 to 2% of the covalently linked cell wall proteins, whereas in cell walls of fks1 and gas1 deletion strains, which contain much less ␤1,3-glucan but more chitin, ␤1,3-glucanase-resistant proteins represented about 40% of the total. We propose that the increased crosslinking of cell wall proteins via ␤1,6-glucan to chitin represents a cell wall repair mechanism in yeast, which is activated in response to cell wall weakening.The cell wall is crucial for the integrity of Saccharomyces cerevisiae. Its rigid structure maintains the shape of the cell and offers protection against harmful environmental conditions (6, 19). The wall is mainly composed of ␤-glucans and mannoproteins, in addition to smaller amounts of chitin and lipids (6). The glucans, which are interwoven with the chitin fibrils, form the inner skeletal layer of the cell wall, whereas the outer layer consists of mannoproteins. The majority of the cell wall mannoproteins are anchored into the wall through covalent linkages to heteropolymers of ␤1,6-and ␤1,3-glucan (18, 26, 41, 43) (Fig. 1). The ␤1,6-glucosyl moiety of these polymers is phosphodiester-linked to protein as shown by its sensitivity to treatment with ice-cold aqueous hydrofluoric acid (HF) and phosphodiesterases (18). This observation, together with data from other studies, pointed to a glycosylphosphatidylinositol (GPI)-derived structure as the attachment site for ␤1, 6-glucan (3, 23, 40, 42, 45). The ␤1,3/␤1,6-glucan heteropolymer was proposed to be identical to the alkali-soluble ␤1,3/␤1,6-glucan studied by Fleet and Manners (7,8). In S. cerevisiae, this alkali-soluble glucan becomes alkali insoluble through a linkage with chitin (11, 24) via a ␤1,4 bond from the terminal reducing residue of chitin to the nonreducing end of ␤1,3-glucan (20). Furthermore, by digesting cell walls with ␤1,3-glucanase, followed by incubation with exochitinase, a heterogeneous high-molecular-weight complex was isolated (21). Structural studies indicated that in this complex the terminal reducing residue of chitin is linked to ␤1,6-glucan (21). The nonreducing end of the ␤1,6-glucan polymer is bound to the GPI-derived glycan part of a cell wall protein, whereas its reducing terminus is linked to ␤1,3-glucan (...

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Section: Discussionsupporting

confidence: 84%

Altered extent of cross-linking of beta1,6-glucosylated mannoproteins to chitin in Saccharomyces cerevisiae mutants with reduced cell wall beta1,3-glucan content

et al. 1997

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“…For the synthesis of the cell wall structural network it has been proposed that GPI anchors have a pivotal constitutive role (7). A truncated GPI anchor which no longer contains inositol and glucosamine is the substrate for a phosphatelinked ␤-1,6-glucan extension (49,58). GPI anchors can be liberated in the periplasmic space by the action of phospholipase C (PI-PLC), as present in S. cerevisiae (15) and abundantly expressed in P. brasiliensis (20), or could be transported to the cell wall in vesicles.…”

Section: Discussionmentioning

confidence: 99%

Human Antibodies against a Purified Glucosylceramide fromCryptococcus neoformansInhibit Cell Budding and Fungal Growth

Rodrigues¹,

et al. 2000

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A major ceramide monohexoside (CMH) was purified from lipidic extracts of Cryptococcus neoformans. This molecule was analyzed by high-performance thin-layer chromatography (HPTLC), gas chromatography coupled with mass spectrometry, and fast atom bombardment-mass spectrometry. The cryptococcal CMH is a ␤-glucosylceramide, with the carbohydrate residue attached to 9-methyl-4,8-sphingadienine in amidic linkage to 2-hydroxyoctadecanoic acid. Sera from patients with cryptococcosis and a few other mycoses reacted with the cryptococcal CMH. Specific antibodies were purified from patients' sera by immunoadsorption on the purified glycolipid followed by protein G affinity chromatography. The purified antibodies to CMH (mainly immunoglobulin G1) bound to different strains and serological types of C. neoformans, as shown by flow cytofluorimetry and immunofluorescence labeling. Transmission electron microscopy of yeasts labeled with immunogoldantibodies to CMH and immunostaining of isolated cell wall lipid extracts separated by HPTLC showed that the cryptococcal CMH predominantly localizes to the fungal cell wall. Confocal microscopy revealed that the ␤-glucosylceramide accumulates mostly at the budding sites of dividing cells with a more disperse distribution at the cell surface of nondividing cells. The increased density of sphingolipid molecules seems to correlate with thickening of the cell wall, hence with its biosynthesis. The addition of human antibodies to CMH to cryptococcal cultures of both acapsular and encapsulated strains of C. neoformans inhibited cell budding and cell growth. This process was complement-independent and reversible upon removal of the antibodies. The present data suggest that the cryptococcal ␤-glucosylceramide is a fungal antigen that plays a role on the cell wall synthesis and yeast budding and that antibodies raised against this component are inhibitory in vitro.

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“…Results to date suggest that the GPI is cleaved between its GlcN residue and Man, whereupon the mannose's reducing end is glycosidically linked to a nonreducing end of b1,6-glucan or to a Glc in a b1,6-Glc chain Fujii et al 1999). The b1,6-glucan to which the GPI-CWP is attached is in turn linked to b1,3-glucan and chitin (Kapteyn et al 1996; Van der Vaart et al 1996;Kollar et al 1997;Fujii et al 1999; Figure 1). Some wall-bound GPI proteins may retain enzymatic activity, whereas others may have a structural role .…”

Section: Cell Wall Mannoproteinsmentioning

confidence: 99%

Architecture and Biosynthesis of the Saccharomyces cerevisiae Cell Wall

2012

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The wall gives a Saccharomyces cerevisiae cell its osmotic integrity; defines cell shape during budding growth, mating, sporulation, and pseudohypha formation; and presents adhesive glycoproteins to other yeast cells. The wall consists of b1,3-and b1,6-glucans, a small amount of chitin, and many different proteins that may bear N-and O-linked glycans and a glycolipid anchor. These components become cross-linked in various ways to form higher-order complexes. Wall composition and degree of cross-linking vary during growth and development and change in response to cell wall stress. This article reviews wall biogenesis in vegetative cells, covering the structure of wall components and how they are cross-linked; the biosynthesis of N-and O-linked glycans, glycosylphosphatidylinositol membrane anchors, b1,3-and b1,6-linked glucans, and chitin; the reactions that cross-link wall components; and the possible functions of enzymatic and nonenzymatic cell wall proteins. TABLE OF CONTENTS Abstract 775Introduction 777

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The β-1,6-glucan containing side-chain of cell wall proteins of Saccharomyces cerevisiae is bound to the glycan core of the GPI moiety

Cited by 35 publications

References 10 publications

Altered extent of cross-linking of beta1,6-glucosylated mannoproteins to chitin in Saccharomyces cerevisiae mutants with reduced cell wall beta1,3-glucan content

Altered extent of cross-linking of beta1,6-glucosylated mannoproteins to chitin in Saccharomyces cerevisiae mutants with reduced cell wall beta1,3-glucan content

Human Antibodies against a Purified Glucosylceramide fromCryptococcus neoformansInhibit Cell Budding and Fungal Growth

Architecture and Biosynthesis of the Saccharomyces cerevisiae Cell Wall

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