Cell cycle dependent coordination of surface layer biogenesis in Caulobacter crescentus

Area of Science:

• Microbiology
• Cell Biology
• Biochemistry

Background:

• Surface layers (S-layers) are protein arrays forming the cell envelope in many prokaryotes.
• Understanding S-layer biogenesis is crucial for comprehending bacterial cell structure and function.

Purpose of the Study:

• To investigate the mechanisms of S-layer biogenesis in the model bacterium Caulobacter crescentus.
• To elucidate the relationship between S-layer assembly and other cell envelope components.

Main Methods:

• Fluorescence microscopy to track S-layer incorporation.
• Light microscopy and electron cryotomography on drug-treated cells.
• Correlated cryo-light microscopy and electron cryotomography.

Main Results:

• S-layer incorporation is localized to cell poles and mid-cell, correlating with growth regions.
• S-layer insertion depends on MreB and lipopolysaccharide integrity.
• S-layer biogenesis follows peptidoglycan synthesis and occurs at sites of high cell wall turnover.
• Discontinuities were observed in the S-layer lattice during insertion.

Conclusions:

• S-layer assembly in C. crescentus is a coordinated process linked to cell wall synthesis.
• The findings provide insights into the spatial and temporal regulation of S-layer formation.
• This study enhances our understanding of bacterial cell envelope construction.