Limits...
Peroxisome synthesis in the absence of preexisting peroxisomes.

South ST, Gould SJ - J. Cell Biol. (1999)

Bottom Line: We also identified human PEX16, a novel integral peroxisomal membrane protein, and found that PBD061 had inactivating mutations in the PEX16 gene.These results demonstrate that peroxisomes do not necessarily arise from division of preexisting peroxisomes.We propose that peroxisomes may form by either of two pathways: one that involves PEX11-mediated division of preexisting peroxisomes, and another that involves PEX16-mediated formation of peroxisomes in the absence of preexisting peroxisomes.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.

ABSTRACT
Zellweger syndrome and related diseases are caused by defective import of peroxisomal matrix proteins. In all previously reported Zellweger syndrome cell lines the defect could be assigned to the matrix protein import pathway since peroxisome membranes were present, and import of integral peroxisomal membrane proteins was normal. However, we report here a Zellweger syndrome patient (PBD061) with an unusual cellular phenotype, an inability to import peroxisomal membrane proteins. We also identified human PEX16, a novel integral peroxisomal membrane protein, and found that PBD061 had inactivating mutations in the PEX16 gene. Previous studies have suggested that peroxisomes arise from preexisting peroxisomes but we find that expression of PEX16 restores the formation of new peroxisomes in PBD061 cells. Peroxisome synthesis and peroxisomal membrane protein import could be detected within 2-3 h of PEX16 injection and was followed by matrix protein import. These results demonstrate that peroxisomes do not necessarily arise from division of preexisting peroxisomes. We propose that peroxisomes may form by either of two pathways: one that involves PEX11-mediated division of preexisting peroxisomes, and another that involves PEX16-mediated formation of peroxisomes in the absence of preexisting peroxisomes.

Show MeSH

Related in: MedlinePlus

Import of PEX16myc can precede P70R import in  peroxisomes of rescued PBD061 cells. PBD061 cells were injected with pcDNA3-PEX16myc and processed for indirect immunofluorescence 3 h later using mouse mAbs specific for the  myc epitope tag (A and C) and rabbit antibodies specific for  P70R (B and D), followed by fluorescein-labeled goat anti– mouse and Texas red–labeled goat anti–sheep secondary antibodies. Bar, 10 μm.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2132891&req=5

Figure 10: Import of PEX16myc can precede P70R import in peroxisomes of rescued PBD061 cells. PBD061 cells were injected with pcDNA3-PEX16myc and processed for indirect immunofluorescence 3 h later using mouse mAbs specific for the myc epitope tag (A and C) and rabbit antibodies specific for P70R (B and D), followed by fluorescein-labeled goat anti– mouse and Texas red–labeled goat anti–sheep secondary antibodies. Bar, 10 μm.

Mentions: We repeated these kinetic studies using the PEX16myc expression vector. PBD061 cells were injected with pcDNA3- PEX16myc and processed for indirect immunofluorescence using antibodies specific for the myc epitope tag and for P70R. As with the wild-type expression vector, rescue could not be detected until 3 h after injection. At this time point, some cells contained punctate structures that contained both PEX16myc and P70R, but a few cells were observed that contained only PEX16myc (Fig. 10).


Peroxisome synthesis in the absence of preexisting peroxisomes.

South ST, Gould SJ - J. Cell Biol. (1999)

Import of PEX16myc can precede P70R import in  peroxisomes of rescued PBD061 cells. PBD061 cells were injected with pcDNA3-PEX16myc and processed for indirect immunofluorescence 3 h later using mouse mAbs specific for the  myc epitope tag (A and C) and rabbit antibodies specific for  P70R (B and D), followed by fluorescein-labeled goat anti– mouse and Texas red–labeled goat anti–sheep secondary antibodies. Bar, 10 μm.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2132891&req=5

Figure 10: Import of PEX16myc can precede P70R import in peroxisomes of rescued PBD061 cells. PBD061 cells were injected with pcDNA3-PEX16myc and processed for indirect immunofluorescence 3 h later using mouse mAbs specific for the myc epitope tag (A and C) and rabbit antibodies specific for P70R (B and D), followed by fluorescein-labeled goat anti– mouse and Texas red–labeled goat anti–sheep secondary antibodies. Bar, 10 μm.
Mentions: We repeated these kinetic studies using the PEX16myc expression vector. PBD061 cells were injected with pcDNA3- PEX16myc and processed for indirect immunofluorescence using antibodies specific for the myc epitope tag and for P70R. As with the wild-type expression vector, rescue could not be detected until 3 h after injection. At this time point, some cells contained punctate structures that contained both PEX16myc and P70R, but a few cells were observed that contained only PEX16myc (Fig. 10).

Bottom Line: We also identified human PEX16, a novel integral peroxisomal membrane protein, and found that PBD061 had inactivating mutations in the PEX16 gene.These results demonstrate that peroxisomes do not necessarily arise from division of preexisting peroxisomes.We propose that peroxisomes may form by either of two pathways: one that involves PEX11-mediated division of preexisting peroxisomes, and another that involves PEX16-mediated formation of peroxisomes in the absence of preexisting peroxisomes.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.

ABSTRACT
Zellweger syndrome and related diseases are caused by defective import of peroxisomal matrix proteins. In all previously reported Zellweger syndrome cell lines the defect could be assigned to the matrix protein import pathway since peroxisome membranes were present, and import of integral peroxisomal membrane proteins was normal. However, we report here a Zellweger syndrome patient (PBD061) with an unusual cellular phenotype, an inability to import peroxisomal membrane proteins. We also identified human PEX16, a novel integral peroxisomal membrane protein, and found that PBD061 had inactivating mutations in the PEX16 gene. Previous studies have suggested that peroxisomes arise from preexisting peroxisomes but we find that expression of PEX16 restores the formation of new peroxisomes in PBD061 cells. Peroxisome synthesis and peroxisomal membrane protein import could be detected within 2-3 h of PEX16 injection and was followed by matrix protein import. These results demonstrate that peroxisomes do not necessarily arise from division of preexisting peroxisomes. We propose that peroxisomes may form by either of two pathways: one that involves PEX11-mediated division of preexisting peroxisomes, and another that involves PEX16-mediated formation of peroxisomes in the absence of preexisting peroxisomes.

Show MeSH
Related in: MedlinePlus