Genetic Screens Identify Additional Genes Implicated in Envelope Remodeling during the Engulfment Stage of Bacillus subtilis Sporulation.

During bacterial endospore formation, the developing spore is internalized into the mother cell through a phagocytic-like process called engulfment, which involves synthesis and hydrolysis of peptidoglycan. Engulfment peptidoglycan hydrolysis requires the widely conserved and well-characterized DMP complex, composed of SpoIID, SpoIIM, and SpoIIP. In contrast, although peptidoglycan synthesis has been implicated in engulfment, the protein players involved are less well defined.

Calcium Contributes to Polarized Targeting of HIV Assembly Machinery by Regulating Complex Stability.

Polarized or precision targeting of protein complexes to their destinations is fundamental to cellular homeostasis, but the mechanism underpinning directional protein delivery is poorly understood. Here, we use the uropod targeting HIV synapse as a model system to show that the viral assembly machinery Gag is copolarized with the intracellular calcium (Ca) gradient and binds specifically with Ca. Conserved glutamic/aspartic acids flanking endosomal sorting complexes required for transport binding motifs are major Ca binding sites.

Chromosome Segregation and Peptidoglycan Remodeling Are Coordinated at a Highly Stabilized Septal Pore to Maintain Bacterial Spore Development.

Asymmetric division, a hallmark of endospore development, generates two cells, a larger mother cell and a smaller forespore. Approximately 75% of the forespore chromosome must be translocated across the division septum into the forespore by the DNA translocase SpoIIIE. Asymmetric division also triggers cell-specific transcription, which initiates septal peptidoglycan remodeling involving synthetic and hydrolytic enzymes.

A dynamic, ring-forming MucB / RseB-like protein influences spore shape in Bacillus subtilis.

How organisms develop into specific shapes is a central question in biology. The maintenance of bacterial shape is connected to the assembly and remodelling of the cell envelope. In endospore-forming bacteria, the pre-spore compartment (the forespore) undergoes morphological changes that result in a spore of defined shape, with a complex, multi-layered cell envelope.