Phylogeny of endocytic components yields insight into the process of nonendosymbiotic organelle evolution
- 15 January 2008
- journal article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences of the United States of America
- Vol. 105 (2), 588-593
- https://doi.org/10.1073/pnas.0707318105
Abstract
The process by which some eukaryotic organelles, for example the endomembrane system, evolved without endosymbiotic input remains poorly understood. This problem largely arises because many major cellular systems predate the last common eukaryotic ancestor (LCEA) and thus do not provide examples of organellogenesis in progress. A model is emerging whereby gene duplication and divergence of multiple "specificity-" or "identity-" encoding proteins for the various endomembranous organelles produced the diversity of nonendosymbiotically derived cellular compartments present in modern eukaryotes. To address this possibility, we analyzed three molecular components of the endocytic membrane-trafficking machinery. Phylogenetic analyses of the endocytic syntaxins, Rab 5, and the beta-adaptins each reveal a pattern of ancestral, undifferentiated endocytic homologues in the LCEA. Subsequently, these undifferentiated progenitors independently duplicated in widely divergent lineages, convergently producing components with similar endocytic roles, e.g., beta1 and beta2-adaptin. In contrast, beta3, beta4, and all other adaptin complex subunits, as well as paralogues of the syntaxins and Rabs specific for the other membrane-trafficking organelles, all evolved before the LCEA. Thus, the process giving rise to the differentiated organelles of the endocytic system appears to have been interrupted by the major speciation event that produced the extant eukaryotic lineages. These results suggest that although many endocytic components evolved before the LCEA, other major features evolved independently and convergently after diversification into the primary eukaryotic supergroups. This finding provides an example of a basic cellular system that was simpler in the LCEA than in many extant eukaryotes and yields insight into nonendosymbiotic organelle evolution.Keywords
This publication has 57 references indexed in Scilit:
- Draft Genome Sequence of the Sexually Transmitted Pathogen Trichomonas vaginalisScience, 2007
- RAxML-VI-HPC: maximum likelihood-based phylogenetic analyses with thousands of taxa and mixed modelsBioinformatics, 2006
- Elucidation of Clathrin-Mediated Endocytosis in Tetrahymena Reveals an Evolutionarily Convergent Recruitment of DynaminPLoS Genetics, 2005
- The New Higher Level Classification of Eukaryotes with Emphasis on the Taxonomy of ProtistsThe Journal of Eukaryotic Microbiology, 2005
- ProtTest: selection of best-fit models of protein evolutionBioinformatics, 2005
- Adaptable adaptors for coated vesiclesTrends in Cell Biology, 2004
- Evolution of the rab family of small GTP-binding proteinsJournal of Molecular Biology, 2001
- T-coffee: a novel method for fast and accurate multiple sequence alignmentJournal of Molecular Biology, 2000
- Gapped BLAST and PSI-BLAST: a new generation of protein database search programsNucleic Acids Research, 1997
- Protein Sorting by Transport VesiclesScience, 1996