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Signal sequence directs localized secretion of bacterial surface proteins
Fredric Carlsson1, Margaretha Stålhammar-Carlemalm, Klas Flärdh
1Department of Laboratory Medicine, Lund University, SE-22362 Lund, Sweden.
Nature
|August 25, 2006
Summary
Bacterial protein secretion is more complex than previously thought. Signal sequences not only direct proteins across membranes but also specify their precise location on the cell surface.
Area of Science:
- Cell Biology
- Microbiology
- Molecular Biology
Background:
- Cell surface protein targeting is essential for all living cells.
- In bacteria, protein secretion across the cytoplasmic membrane is typically mediated by N-terminal signal sequences.
- Mechanisms for localized protein secretion in bacteria are not well understood.
Purpose of the Study:
- To investigate the mechanisms of localized protein secretion in Streptococcus pyogenes.
- To determine if signal sequences contain information for subcellular targeting of surface proteins.
Main Methods:
- Analysis of localized secretion of M protein and protein F (PrtF) in Streptococcus pyogenes.
- Investigation of the role of signal sequences in directing protein secretion to specific subcellular regions.
Main Results:
- Signal sequences of M protein and PrtF direct secretion to distinct subcellular locations.
- M protein signal sequence promotes secretion at the division septum.
- PrtF signal sequence promotes secretion at the old pole.
Conclusions:
- Bacterial signal sequences possess dual functions: promoting secretion and directing subcellular localization.
- This finding reveals a new layer of complexity in protein translocation.
- Bacterial systems offer valuable models for studying fundamental cell-biological processes.
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