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Cdc1 removes the ethanolamine phosphate of the first mannose of GPI anchors and thereby facilitates the integration of GPI proteins into the yeast cell wall.

Vazquez HM, Vionnet C, Roubaty C, Conzelmann A - Mol. Biol. Cell (2014)

Bottom Line: We find that the essential CDC1 gene can be deleted in mcd4∆ cells, which do not attach EtN-P to mannose 1 of the GPI anchor, suggesting that Cdc1 removes the EtN-P added by Mcd4.Cdc1-314(ts) mutants do not accumulate GPI proteins in the ER but have a partial secretion block later in the secretory pathway.This suggests that the presumed transglycosidases Dfg5 and Dcw1 of cdc1-314(ts) transfer GPI proteins to cell wall β1,6-glucans inefficiently.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, University of Fribourg, CH-1700 Fribourg, Switzerland.

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GPI anchor remodeling and subsequent attachment to the cell wall. Essential genes are indicated in blue. Mature GPI anchor lipids (left) contain EtN-Ps on Man1, Man2, and Man3; their addition is catalyzed by MCD4, GPI7, and GPI13, respectively. After the protein is attached to the GPI lipid by the transamidase complex, the lipid moiety is remodeled by Bst1, Per1, Gup1, and Cwh43 (middle). At some time during lipid remodeling, EtN-Ps may be removed from Man1 and Man2. At the plasma membrane, Man1 of the anchor of GPI-CWPs is transferred and covalently linked to β1,6-glucans. This reaction is presumably catalyzed by Dcw1 and Dfg5.
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Figure 1: GPI anchor remodeling and subsequent attachment to the cell wall. Essential genes are indicated in blue. Mature GPI anchor lipids (left) contain EtN-Ps on Man1, Man2, and Man3; their addition is catalyzed by MCD4, GPI7, and GPI13, respectively. After the protein is attached to the GPI lipid by the transamidase complex, the lipid moiety is remodeled by Bst1, Per1, Gup1, and Cwh43 (middle). At some time during lipid remodeling, EtN-Ps may be removed from Man1 and Man2. At the plasma membrane, Man1 of the anchor of GPI-CWPs is transferred and covalently linked to β1,6-glucans. This reaction is presumably catalyzed by Dcw1 and Dfg5.

Mentions: The activity transferring GPI proteins from the plasma membrane onto β-glucans may reside with Dfg5 and Dcw1, two highly homologous GPI proteins (54% identity; Kitagaki et al., 2002). During the transfer of GPI-CWPs to cell wall glucans, the glucosamine–inositol–phospholipid moiety of the anchor is lost, whereas four to five mannoses (Man), the phosphodiester bond, and the bridging ethanolamine (EtN) remain attached to the protein (Figure 1). Therefore Dfg5 and Dcw1, having homology with bacterial endomannosidases, are proposed to cleave the Manα1,4glucosamine linkage of the GPI anchor and to reattach the liberated Man residue with the attached GPI protein to β1,6-glucans of the cell wall (Kollar et al., 1997; Fujii et al., 1999; Kitagaki et al., 2002). Simultaneous deletion of DFG5 and DCW1 is lethal, suggesting that the covalent attachment of GPI-CWPs to glucans is essential, and this remains true even if cells receive osmotic support (Kitagaki et al., 2002).


Cdc1 removes the ethanolamine phosphate of the first mannose of GPI anchors and thereby facilitates the integration of GPI proteins into the yeast cell wall.

Vazquez HM, Vionnet C, Roubaty C, Conzelmann A - Mol. Biol. Cell (2014)

GPI anchor remodeling and subsequent attachment to the cell wall. Essential genes are indicated in blue. Mature GPI anchor lipids (left) contain EtN-Ps on Man1, Man2, and Man3; their addition is catalyzed by MCD4, GPI7, and GPI13, respectively. After the protein is attached to the GPI lipid by the transamidase complex, the lipid moiety is remodeled by Bst1, Per1, Gup1, and Cwh43 (middle). At some time during lipid remodeling, EtN-Ps may be removed from Man1 and Man2. At the plasma membrane, Man1 of the anchor of GPI-CWPs is transferred and covalently linked to β1,6-glucans. This reaction is presumably catalyzed by Dcw1 and Dfg5.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

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Figure 1: GPI anchor remodeling and subsequent attachment to the cell wall. Essential genes are indicated in blue. Mature GPI anchor lipids (left) contain EtN-Ps on Man1, Man2, and Man3; their addition is catalyzed by MCD4, GPI7, and GPI13, respectively. After the protein is attached to the GPI lipid by the transamidase complex, the lipid moiety is remodeled by Bst1, Per1, Gup1, and Cwh43 (middle). At some time during lipid remodeling, EtN-Ps may be removed from Man1 and Man2. At the plasma membrane, Man1 of the anchor of GPI-CWPs is transferred and covalently linked to β1,6-glucans. This reaction is presumably catalyzed by Dcw1 and Dfg5.
Mentions: The activity transferring GPI proteins from the plasma membrane onto β-glucans may reside with Dfg5 and Dcw1, two highly homologous GPI proteins (54% identity; Kitagaki et al., 2002). During the transfer of GPI-CWPs to cell wall glucans, the glucosamine–inositol–phospholipid moiety of the anchor is lost, whereas four to five mannoses (Man), the phosphodiester bond, and the bridging ethanolamine (EtN) remain attached to the protein (Figure 1). Therefore Dfg5 and Dcw1, having homology with bacterial endomannosidases, are proposed to cleave the Manα1,4glucosamine linkage of the GPI anchor and to reattach the liberated Man residue with the attached GPI protein to β1,6-glucans of the cell wall (Kollar et al., 1997; Fujii et al., 1999; Kitagaki et al., 2002). Simultaneous deletion of DFG5 and DCW1 is lethal, suggesting that the covalent attachment of GPI-CWPs to glucans is essential, and this remains true even if cells receive osmotic support (Kitagaki et al., 2002).

Bottom Line: We find that the essential CDC1 gene can be deleted in mcd4∆ cells, which do not attach EtN-P to mannose 1 of the GPI anchor, suggesting that Cdc1 removes the EtN-P added by Mcd4.Cdc1-314(ts) mutants do not accumulate GPI proteins in the ER but have a partial secretion block later in the secretory pathway.This suggests that the presumed transglycosidases Dfg5 and Dcw1 of cdc1-314(ts) transfer GPI proteins to cell wall β1,6-glucans inefficiently.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, University of Fribourg, CH-1700 Fribourg, Switzerland.

Show MeSH
Related in: MedlinePlus