The CRY2-CIBN system enables precise, light-controlled recruitment of proteins to various subcellular locations in E. coli. By tagging CIBN to proteins of interest and fusing CRY2 with a fluorescent reporter, researchers can dynamically control protein localization. The system’s flexibility allows for modulation of expression levels to minimize background interactions while maintaining fast recruitment speeds. Applications include targeting proteins to chromosomal DNA, cell poles, midcell, and inner membranes. The system’s reversibility and sensitivity to green light further enhance its utility for studying dynamic cellular processes. While adaptable to other bacterial species, its efficiency varies, highlighting the need for species-specific optimization.
The CRY2-CIBN system allows precise, light-controlled protein recruitment to various subcellular locations in E. coli. By tagging CIBN to proteins of interest and fusing CRY2 with a fluorescent reporter, researchers can dynamically control protein localization. The system’s flexibility enables modulation of expression levels to minimize background interactions while maintaining fast recruitment speeds. Applications include targeting proteins to chromosomal DNA, cell poles, midcell, and inner membranes. The system’s reversibility and sensitivity to green light enhance its utility for studying dynamic cellular processes. While adaptable to other bacterial species, efficiency varies, necessitating species-specific optimization.
The CRY2-CIBN system has been demonstrated to effectively achieve light-dependent protein recruitment in E. coli cells. Here’s an organized and SEO-friendly summary of the findings:
Key Considerations for Using the CRY2-CIBN System in E. coli
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Expression Strategies:
- Two plasmid systems were employed to control CRY2 and CIBN expression levels, crucial for minimizing background interactions and ensuring efficient recruitment.
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Subcellular Compartments Targeted:
- Chromosomal DNA: Recruitment to oriC regions was achieved using a TetR-CIBN fusion. Rapid foci formation (reaching 90% in ~85 seconds) and reversible dissociation (relaxation time ~10 minutes) were observed.
- Cell Pole: PopZ protein scaffolds enabled recruitment to cell poles with rapid kinetics (90% in ~8 seconds).
- Inner Membrane: By fusing CIBN to an amphipathic helix, recruitment to the inner membrane was demonstrated, though hetero-cluster formation varied.
- Midcell (Z-ring): Using ZapA-CIBN, CRY2-mCherry was recruited to midcell, leading to successful LInC assays for cell division inhibition.
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Green Light Sensitivity: Green light (561 nm) modulates the CRY2-CIBN interaction by reducing the level of activated CRY2, without significantly altering association kinetics.
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Adaptation to Other Species:
- B. subtilis: Partial adaptation was achieved with midcell recruitment, though less efficient than in E. coli.
- C. crescentus: Recruitment to cell poles was observed but with low efficiency.
- S. pneumoniae: No successful recruitment was observed, likely due to challenges in CRY2 folding or cofactor availability.
- Applications:
- The system enables precise, temporal control of protein localization, with potential applications in studying bacterial cell biology processes, such as cell division and signaling.
Conclusion
The CRY2-CIBN system offers a powerful optogenetic tool for studying dynamic protein interactions and subcellular processes in E. coli, with some success in other bacterial species. Continued optimization may expand its applicability to other systems.
