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Peroxisome reintroduction in Hansenula polymorpha requires Pex25 and Rho1.

Saraya R, Krikken AM, Veenhuis M, van der Klei IJ - J. Cell Biol. (2011)

Bottom Line: Pex25 cells were not themselves peroxisome deficient but instead contained a slightly increased number of peroxisomes.Peroxisomes reappeared in pex11 pex25 cells upon synthesis of Pex25, but not of Pex11.These data therefore provide new and detailed insight into factors important for de novo peroxisome formation in yeast.

View Article: PubMed Central - HTML - PubMed

Affiliation: Molecular Cell Biology, Groningen Biomolecular Sciences and Biotechnology Institute, Kluyver Centre for Genomics of Industrial Fermentation, University of Groningen, 9700 CC Groningen, Netherlands.

ABSTRACT
We identified two proteins, Pex25 and Rho1, which are involved in reintroduction of peroxisomes in peroxisome-deficient yeast cells. These are, together with Pex3, the first proteins identified as essential for this process. Of the three members of the Hansenula polymorpha Pex11 protein family-Pex11, Pex25, and Pex11C-only Pex25 was required for reintroduction of peroxisomes into a peroxisome-deficient mutant strain. In peroxisome-deficient pex3 cells, Pex25 localized to structures adjacent to the ER, whereas in wild-type cells it localized to peroxisomes. Pex25 cells were not themselves peroxisome deficient but instead contained a slightly increased number of peroxisomes. Interestingly, pex11 pex25 double deletion cells, in which both peroxisome fission (due to the deletion of PEX11) and reintroduction (due to deletion of PEX25) was blocked, did display a peroxisome-deficient phenotype. Peroxisomes reappeared in pex11 pex25 cells upon synthesis of Pex25, but not of Pex11. Reintroduction in the presence of Pex25 required the function of the GTPase Rho1. These data therefore provide new and detailed insight into factors important for de novo peroxisome formation in yeast.

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Quantification of peroxisome numbers in various H. polymorpha strains. Cells were grown on glycerol/methanol mixtures for 16 h. The number of peroxisomes in nonbudding cells was counted from randomly taken CLSM images. For each sample peroxisomes were counted from 2 × 100 cells from two independent experiments. The frequency distributions of cells with number of peroxisomes per cell are shown. Bars represent the SEM. (A) Frequency distributions of WT, pex25, pex11C, and pex25 pex11C cells. (B) Distributions in WT, pex11, pex11 pex11C, and pex11 pex25. In pex11 pex25 peroxisomes could not be detected using the fluorescent matrix marker protein (DsRed-SKL).
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fig2: Quantification of peroxisome numbers in various H. polymorpha strains. Cells were grown on glycerol/methanol mixtures for 16 h. The number of peroxisomes in nonbudding cells was counted from randomly taken CLSM images. For each sample peroxisomes were counted from 2 × 100 cells from two independent experiments. The frequency distributions of cells with number of peroxisomes per cell are shown. Bars represent the SEM. (A) Frequency distributions of WT, pex25, pex11C, and pex25 pex11C cells. (B) Distributions in WT, pex11, pex11 pex11C, and pex11 pex25. In pex11 pex25 peroxisomes could not be detected using the fluorescent matrix marker protein (DsRed-SKL).

Mentions: The role of the three Pex11 family proteins in peroxisome formation was analyzed in various deletion strains. Cells of single deletion strains (designated pex11, pex25, and pex11C) grew like wild-type (WT) controls on glucose. However, on methanol the doubling times of pex11 and pex25 cultures (td = 8 h) were twice that of identically grown WT or pex11C cultures (td = 4 h). Quantitative analyses of peroxisome numbers (Fig. 2; Table I) revealed that deletion of PEX11 resulted in a strong reduction in peroxisome numbers in methanol-induced cells, whereas in pex25 cells a slight increase was observed. Deletion of PEX11C had no effect on peroxisome numbers (Fig. 2; Table I). Deletion of PEX11C in pex11 or pex25 cells also had no effect on the phenotype of the initial single mutants (Figs. 1 and 2; Table I). These data confirm the role of Pex11 in peroxisome proliferation, whereas Pex25 has a slightly negative effect in this process.


Peroxisome reintroduction in Hansenula polymorpha requires Pex25 and Rho1.

Saraya R, Krikken AM, Veenhuis M, van der Klei IJ - J. Cell Biol. (2011)

Quantification of peroxisome numbers in various H. polymorpha strains. Cells were grown on glycerol/methanol mixtures for 16 h. The number of peroxisomes in nonbudding cells was counted from randomly taken CLSM images. For each sample peroxisomes were counted from 2 × 100 cells from two independent experiments. The frequency distributions of cells with number of peroxisomes per cell are shown. Bars represent the SEM. (A) Frequency distributions of WT, pex25, pex11C, and pex25 pex11C cells. (B) Distributions in WT, pex11, pex11 pex11C, and pex11 pex25. In pex11 pex25 peroxisomes could not be detected using the fluorescent matrix marker protein (DsRed-SKL).
© Copyright Policy - openaccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3105547&req=5

fig2: Quantification of peroxisome numbers in various H. polymorpha strains. Cells were grown on glycerol/methanol mixtures for 16 h. The number of peroxisomes in nonbudding cells was counted from randomly taken CLSM images. For each sample peroxisomes were counted from 2 × 100 cells from two independent experiments. The frequency distributions of cells with number of peroxisomes per cell are shown. Bars represent the SEM. (A) Frequency distributions of WT, pex25, pex11C, and pex25 pex11C cells. (B) Distributions in WT, pex11, pex11 pex11C, and pex11 pex25. In pex11 pex25 peroxisomes could not be detected using the fluorescent matrix marker protein (DsRed-SKL).
Mentions: The role of the three Pex11 family proteins in peroxisome formation was analyzed in various deletion strains. Cells of single deletion strains (designated pex11, pex25, and pex11C) grew like wild-type (WT) controls on glucose. However, on methanol the doubling times of pex11 and pex25 cultures (td = 8 h) were twice that of identically grown WT or pex11C cultures (td = 4 h). Quantitative analyses of peroxisome numbers (Fig. 2; Table I) revealed that deletion of PEX11 resulted in a strong reduction in peroxisome numbers in methanol-induced cells, whereas in pex25 cells a slight increase was observed. Deletion of PEX11C had no effect on peroxisome numbers (Fig. 2; Table I). Deletion of PEX11C in pex11 or pex25 cells also had no effect on the phenotype of the initial single mutants (Figs. 1 and 2; Table I). These data confirm the role of Pex11 in peroxisome proliferation, whereas Pex25 has a slightly negative effect in this process.

Bottom Line: Pex25 cells were not themselves peroxisome deficient but instead contained a slightly increased number of peroxisomes.Peroxisomes reappeared in pex11 pex25 cells upon synthesis of Pex25, but not of Pex11.These data therefore provide new and detailed insight into factors important for de novo peroxisome formation in yeast.

View Article: PubMed Central - HTML - PubMed

Affiliation: Molecular Cell Biology, Groningen Biomolecular Sciences and Biotechnology Institute, Kluyver Centre for Genomics of Industrial Fermentation, University of Groningen, 9700 CC Groningen, Netherlands.

ABSTRACT
We identified two proteins, Pex25 and Rho1, which are involved in reintroduction of peroxisomes in peroxisome-deficient yeast cells. These are, together with Pex3, the first proteins identified as essential for this process. Of the three members of the Hansenula polymorpha Pex11 protein family-Pex11, Pex25, and Pex11C-only Pex25 was required for reintroduction of peroxisomes into a peroxisome-deficient mutant strain. In peroxisome-deficient pex3 cells, Pex25 localized to structures adjacent to the ER, whereas in wild-type cells it localized to peroxisomes. Pex25 cells were not themselves peroxisome deficient but instead contained a slightly increased number of peroxisomes. Interestingly, pex11 pex25 double deletion cells, in which both peroxisome fission (due to the deletion of PEX11) and reintroduction (due to deletion of PEX25) was blocked, did display a peroxisome-deficient phenotype. Peroxisomes reappeared in pex11 pex25 cells upon synthesis of Pex25, but not of Pex11. Reintroduction in the presence of Pex25 required the function of the GTPase Rho1. These data therefore provide new and detailed insight into factors important for de novo peroxisome formation in yeast.

Show MeSH
Related in: MedlinePlus