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Origin and evolution of the peroxisomal proteome
Toni Gabaldón1, Berend Snel, Frank van Zimmeren
1CMBI, Center for Molecular and Biomolecular Informatics, NCMLS, Nijmegen Center for Molecular Life Sciences, Radboud University Nijmegen Medical Center, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands. tgabaldon@cipf.es
Biology Direct
|March 25, 2006
Summary
Peroxisomes originated from the endoplasmic reticulum, not through endosymbiosis. Phylogenetic analysis reveals proteins were recruited from within the early eukaryotic cell, challenging the endosymbiotic theory for peroxisome evolution.
Area of Science:
- Cell Biology
- Evolutionary Biology
- Biochemistry
Background:
- Peroxisomes are vital eukaryotic organelles involved in oxidative reactions, with conserved biogenesis systems suggesting a single evolutionary origin.
- The evolutionary origin of peroxisomes is debated, with endosymbiotic theories challenged by evidence of ER-derived formation and gene complementation in peroxisome-deficient cells.
- Unlike mitochondria and chloroplasts, peroxisomes lack their own genome, hindering classical evolutionary analyses.
Purpose of the Study:
- To investigate the evolutionary origin of peroxisomes using large-scale phylogenetic analyses.
- To determine whether peroxisomes arose from endosymbiosis or through internal recruitment of proteins within early eukaryotes.
- To elucidate the relationship between peroxisome biogenesis and the Endoplasmic Reticulum.
Main Methods:
- Conducted large-scale phylogenetic analyses of peroxisomal proteomes from yeast and rat.
- Analyzed the origin and homology of peroxisomal proteins, including those involved in biogenesis and enzymatic functions.
- Compared peroxisomal protein homology with proteins from other cellular compartments, particularly the Endoplasmic Reticulum.
Main Results:
- The majority of peroxisomal proteins (39-58%) are of eukaryotic origin, including all proteins essential for organelle biogenesis and maintenance.
- A significant fraction of peroxisomal proteins (13-18%), primarily enzymes, show alpha-proteobacterial origins, suggesting recruitment from mitochondria.
- Key peroxisome biogenesis and maintenance proteins are homologous to proteins from the Endoplasmic Reticulum Assisted Decay pathway, supporting ER involvement.
Conclusions:
- Peroxisomes did not originate via endosymbiosis; their protein components were recruited from existing pools within the primitive eukaryotic cell.
- Phylogenetic reconstruction indicates that peroxisomes, both ontogenetically and phylogenetically, originate from the Endoplasmic Reticulum.
- The study refutes the endosymbiotic origin of peroxisomes and establishes their derivation from the ER.