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11:33
Monitoring the Assembly of a Secreted Bacterial Virulence Factor Using Site-specific Crosslinking
Published on: December 17, 2013
Small proteins link coat and cortex assembly during sporulation in Bacillus subtilis
Sarah E Ebmeier1, Irene S Tan, Katie Rose Clapham
1Laboratory of Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
Molecular Microbiology
|April 3, 2012
Summary
A newly discovered protein, CmpA, acts as a checkpoint in Bacillus subtilis spore formation. It ensures proper assembly of the spore coat before allowing the inner cortex layer to form, coordinating development.
Area of Science:
- Microbiology
- Bacterial spore formation
- Cellular morphogenesis
Background:
- Bacillus subtilis spores have two layers: a peptidoglycan cortex and a proteinaceous coat.
- The coat's basement layer is anchored by the SpoVM protein.
- Coordinated assembly of spore coat and cortex is crucial but poorly understood.
Purpose of the Study:
- To investigate the mechanisms coordinating Bacillus subtilis spore coat and cortex morphogenesis.
- To identify novel proteins involved in spore layer assembly regulation.
Main Methods:
- Gene expression analysis under sporulation-specific transcription factors.
- Protein localization studies on developing spores.
- Gene deletion and overexpression experiments (e.g., deletion of cmpA).
Main Results:
- A previously un-annotated gene, cmpA, encodes a 37-amino-acid protein, CmpA.
- CmpA localizes to the developing spore surface.
- Deletion of cmpA accelerated sporulation; CmpA overproduction delayed sporulation and inhibited cortex assembly.
- CmpA is removed post-translationally after coat assembly initiation.
Conclusions:
- CmpA acts as a developmental checkpoint protein in Bacillus subtilis sporulation.
- CmpA represses cortex assembly until coat assembly is initiated, ensuring proper morphogenesis.
- This mechanism coordinates the development of the spore's outer coat and inner cortex layers.
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