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PHD1 links cell-cycle progression to oxygen sensing through hydroxylation of the centrosomal protein Cep192.

Moser SC, Bensaddek D, Ortmann B, Maure JF, Mudie S, Blow JJ, Lamond AI, Swedlow JR, Rocha S - Dev. Cell (2013)

Bottom Line: Importantly, PHD1 is also required for primary cilia formation.Cep192 is hydroxylated by PHD1 on proline residue 1717.This hydroxylation is required for binding of the E3 ubiquitin ligase SCF(Skp2), which ubiquitinates Cep192, targeting it for proteasomal degradation.

View Article: PubMed Central - PubMed

Affiliation: Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK.

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Cep192 Overexpression Phenotype Overlaps with PHD1 Depletion(A) Cep192 overexpression interferes with centrosomal recruitment of γ-tubulin. HeLa cells were transfected with Cep192-GFP (green) and stained for pericentrin (red) and γ-tubulin (blue). The scale bar represents 1 μm.(B) Quantification of the relative fluorescence intensity of γ-tubulin. Error bars represent SD.(C) Overexpression of Cep192 interferes with centriolar duplication. HeLa cells transfected with Cep192-GFP were stained for centrin (green) and DNA (blue). Phenotype was observed in n = 8/20. The scale bar represents 5 μm.(D) Schematic of the proposed model for PHD1 regulation of Cep192.
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fig7: Cep192 Overexpression Phenotype Overlaps with PHD1 Depletion(A) Cep192 overexpression interferes with centrosomal recruitment of γ-tubulin. HeLa cells were transfected with Cep192-GFP (green) and stained for pericentrin (red) and γ-tubulin (blue). The scale bar represents 1 μm.(B) Quantification of the relative fluorescence intensity of γ-tubulin. Error bars represent SD.(C) Overexpression of Cep192 interferes with centriolar duplication. HeLa cells transfected with Cep192-GFP were stained for centrin (green) and DNA (blue). Phenotype was observed in n = 8/20. The scale bar represents 5 μm.(D) Schematic of the proposed model for PHD1 regulation of Cep192.

Mentions: Our results so far suggested that Cep192 is required to ensure proper centrosome function. However, PHD1 depletion results in higher levels of Cep192, but with similar effects on centrosomal function to Cep192 depletion. Therefore, we tested whether overexpression of Cep192 would have similar effects on the centrosome as PHD1 or Cep192 depletion. When we transfected HeLa cells with WT Cep192 cDNA, we noticed that γ-tubulin levels at the centrosome decreased (Figures 7A and 7B), whereas transfected mitotic cells showed reduced numbers of centrioles (Figure 7C). These results indicate that overexpression of WT Cep192 has serious consequences, possibly because excess amounts of Cep192 can interfere with centriolar duplication by disrupting the recruitment of γ-tubulin by the centrosome.


PHD1 links cell-cycle progression to oxygen sensing through hydroxylation of the centrosomal protein Cep192.

Moser SC, Bensaddek D, Ortmann B, Maure JF, Mudie S, Blow JJ, Lamond AI, Swedlow JR, Rocha S - Dev. Cell (2013)

Cep192 Overexpression Phenotype Overlaps with PHD1 Depletion(A) Cep192 overexpression interferes with centrosomal recruitment of γ-tubulin. HeLa cells were transfected with Cep192-GFP (green) and stained for pericentrin (red) and γ-tubulin (blue). The scale bar represents 1 μm.(B) Quantification of the relative fluorescence intensity of γ-tubulin. Error bars represent SD.(C) Overexpression of Cep192 interferes with centriolar duplication. HeLa cells transfected with Cep192-GFP were stained for centrin (green) and DNA (blue). Phenotype was observed in n = 8/20. The scale bar represents 5 μm.(D) Schematic of the proposed model for PHD1 regulation of Cep192.
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fig7: Cep192 Overexpression Phenotype Overlaps with PHD1 Depletion(A) Cep192 overexpression interferes with centrosomal recruitment of γ-tubulin. HeLa cells were transfected with Cep192-GFP (green) and stained for pericentrin (red) and γ-tubulin (blue). The scale bar represents 1 μm.(B) Quantification of the relative fluorescence intensity of γ-tubulin. Error bars represent SD.(C) Overexpression of Cep192 interferes with centriolar duplication. HeLa cells transfected with Cep192-GFP were stained for centrin (green) and DNA (blue). Phenotype was observed in n = 8/20. The scale bar represents 5 μm.(D) Schematic of the proposed model for PHD1 regulation of Cep192.
Mentions: Our results so far suggested that Cep192 is required to ensure proper centrosome function. However, PHD1 depletion results in higher levels of Cep192, but with similar effects on centrosomal function to Cep192 depletion. Therefore, we tested whether overexpression of Cep192 would have similar effects on the centrosome as PHD1 or Cep192 depletion. When we transfected HeLa cells with WT Cep192 cDNA, we noticed that γ-tubulin levels at the centrosome decreased (Figures 7A and 7B), whereas transfected mitotic cells showed reduced numbers of centrioles (Figure 7C). These results indicate that overexpression of WT Cep192 has serious consequences, possibly because excess amounts of Cep192 can interfere with centriolar duplication by disrupting the recruitment of γ-tubulin by the centrosome.

Bottom Line: Importantly, PHD1 is also required for primary cilia formation.Cep192 is hydroxylated by PHD1 on proline residue 1717.This hydroxylation is required for binding of the E3 ubiquitin ligase SCF(Skp2), which ubiquitinates Cep192, targeting it for proteasomal degradation.

View Article: PubMed Central - PubMed

Affiliation: Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK.

Show MeSH
Related in: MedlinePlus