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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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Sorbitol normalizes surface transport of GPI proteins and actin depolarization in cdc1 cells. WT and cdc1 cells expressing Gas1-GFP (A) or Crh2-GFP (B) under their own promoters and present on centromeric plasmids were grown overnight at the indicated temperatures without or with 1 M sorbitol (+ 1MS). Cells were viewed under a fluorescence microscope. Magnification is the same in all pictures; scale bars: 5 μm. (C) actin patches and cables were stained with rhodamine phalloidin in cells grown overnight under the indicated conditions. (D and E) Actin polarization in cells grown overnight at 33 (D) or 37°C (E) was quantified by measuring the phalloidin fluorescence density in buds and their mothers and then calculating the bud/mother density ratios. Each dot represents a budded cell; bud/mother density ratios are plotted as a function of the bud/mother size ratio and data were subjected to linear regression analysis. Note that these fluorescence density ratios are quite small, because they do not account for the volume but only the area occupied by buds and mothers.
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Figure 7: Sorbitol normalizes surface transport of GPI proteins and actin depolarization in cdc1 cells. WT and cdc1 cells expressing Gas1-GFP (A) or Crh2-GFP (B) under their own promoters and present on centromeric plasmids were grown overnight at the indicated temperatures without or with 1 M sorbitol (+ 1MS). Cells were viewed under a fluorescence microscope. Magnification is the same in all pictures; scale bars: 5 μm. (C) actin patches and cables were stained with rhodamine phalloidin in cells grown overnight under the indicated conditions. (D and E) Actin polarization in cells grown overnight at 33 (D) or 37°C (E) was quantified by measuring the phalloidin fluorescence density in buds and their mothers and then calculating the bud/mother density ratios. Each dot represents a budded cell; bud/mother density ratios are plotted as a function of the bud/mother size ratio and data were subjected to linear regression analysis. Note that these fluorescence density ratios are quite small, because they do not account for the volume but only the area occupied by buds and mothers.

Mentions: The reason why emp24∆, per1∆, and gup1∆ restore the growth of cdc1 at 30°C may be that all these mutants reportedly accumulate GPI proteins in the ER (Fujita and Jigami, 2008; Castillon et al., 2011; Figure S3B). This would prolong the time span during which newly synthesized GPI proteins can be acted on by the residual phosphodiesterase activity of Cdc1-314 in the ER, thereby increasing the percentage of correctly processed anchors. It may also be, however, that the strong UPR induced by deletions such as emp24∆, per1∆, and gup1∆ (Jonikas et al., 2009) would help cdc1 cells to overcome its late secretion block (see Figure 7A later in this article). Indeed, the similar sec1ts block is partially cured by a strong UPR (Chang et al., 2004). On the other hand, subsistence of the acyl on the inositol moiety in bst1∆ may impede the interaction of the GPI anchor with Cdc1, leading to the strongly negative interaction of bst1∆ and cdc1 (Table S1).


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)

Sorbitol normalizes surface transport of GPI proteins and actin depolarization in cdc1 cells. WT and cdc1 cells expressing Gas1-GFP (A) or Crh2-GFP (B) under their own promoters and present on centromeric plasmids were grown overnight at the indicated temperatures without or with 1 M sorbitol (+ 1MS). Cells were viewed under a fluorescence microscope. Magnification is the same in all pictures; scale bars: 5 μm. (C) actin patches and cables were stained with rhodamine phalloidin in cells grown overnight under the indicated conditions. (D and E) Actin polarization in cells grown overnight at 33 (D) or 37°C (E) was quantified by measuring the phalloidin fluorescence density in buds and their mothers and then calculating the bud/mother density ratios. Each dot represents a budded cell; bud/mother density ratios are plotted as a function of the bud/mother size ratio and data were subjected to linear regression analysis. Note that these fluorescence density ratios are quite small, because they do not account for the volume but only the area occupied by buds and mothers.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

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Figure 7: Sorbitol normalizes surface transport of GPI proteins and actin depolarization in cdc1 cells. WT and cdc1 cells expressing Gas1-GFP (A) or Crh2-GFP (B) under their own promoters and present on centromeric plasmids were grown overnight at the indicated temperatures without or with 1 M sorbitol (+ 1MS). Cells were viewed under a fluorescence microscope. Magnification is the same in all pictures; scale bars: 5 μm. (C) actin patches and cables were stained with rhodamine phalloidin in cells grown overnight under the indicated conditions. (D and E) Actin polarization in cells grown overnight at 33 (D) or 37°C (E) was quantified by measuring the phalloidin fluorescence density in buds and their mothers and then calculating the bud/mother density ratios. Each dot represents a budded cell; bud/mother density ratios are plotted as a function of the bud/mother size ratio and data were subjected to linear regression analysis. Note that these fluorescence density ratios are quite small, because they do not account for the volume but only the area occupied by buds and mothers.
Mentions: The reason why emp24∆, per1∆, and gup1∆ restore the growth of cdc1 at 30°C may be that all these mutants reportedly accumulate GPI proteins in the ER (Fujita and Jigami, 2008; Castillon et al., 2011; Figure S3B). This would prolong the time span during which newly synthesized GPI proteins can be acted on by the residual phosphodiesterase activity of Cdc1-314 in the ER, thereby increasing the percentage of correctly processed anchors. It may also be, however, that the strong UPR induced by deletions such as emp24∆, per1∆, and gup1∆ (Jonikas et al., 2009) would help cdc1 cells to overcome its late secretion block (see Figure 7A later in this article). Indeed, the similar sec1ts block is partially cured by a strong UPR (Chang et al., 2004). On the other hand, subsistence of the acyl on the inositol moiety in bst1∆ may impede the interaction of the GPI anchor with Cdc1, leading to the strongly negative interaction of bst1∆ and cdc1 (Table S1).

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