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PPR-SMRs: ancient proteins with enigmatic functions.
Sheng Liu1, Joanna Melonek1, Laura M Boykin2
1Australian Research Council Centre of Excellence in Plant Energy Biology; The University of Western Australia; Crawley, WA Australia.
RNA Biology
|September 6, 2013
Summary
Pentatricopeptide repeat-small MutS-related (PPR-SMR) proteins are crucial for chloroplast biogenesis and signaling in plants. Phylogenetic analysis reveals their ancient origins within the Viridiplantae clade.
Area of Science:
- Plant Biology
- Molecular Evolution
- Cellular Biology
Background:
- Pentatricopeptide repeat (PPR) proteins are a large family in plants.
- A small subset of PPR proteins possess a C-terminal small MutS-related (SMR) domain.
- These PPR-SMR proteins are significant in chloroplast biogenesis and retrograde signaling.
Purpose of the Study:
- To review current knowledge on PPR-SMR proteins.
- To analyze their occurrence and evolutionary history in Viridiplantae.
- To discuss their potential functions, including endonucleolytic activity.
Main Methods:
- Review of proteomic and mutant studies in Arabidopsis and maize.
- Phylogenetic analysis of PPR-SMR proteins across various organisms.
- Comparative analysis of SMR domain conservation.
Main Results:
- PPR-SMR proteins are found in species with chloroplasts.
- Phylogenetic analysis indicates early evolution of PPR-SMR proteins in the Viridiplantae clade.
- Conservation of SMR domains suggests potential shared functions, possibly endonucleolytic activity.
Conclusions:
- PPR-SMR proteins have a long evolutionary history within photosynthetic eukaryotes.
- Their conserved structure and potential functions highlight their importance in chloroplast biology.
- Further research is needed to fully elucidate the roles of these proteins.
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