Figure 4.

Respective roles of aPBP, the elongasome and the divisome. The synthesis of PG is carried out by three distinct complexes, namely, the elongasome, the divisome and the repairome. The elongasome is responsible for constructing the foundational lateral PG structure, and the GTase RodA plays a key role in this process. The repairome, which includes aPBPs, is involved in repairing and strengthening the PG meshwork in collaboration with the elongasome complex. In B. subtilis, PBP1a, the main aPBP, has an extracytoplasmic IDR that guides the GTase to gaps in the PG meshwork for repair. When aPBPs are absent, cells increase the expression of rodA, mreBH and lytE genes to upregulate elongasome activity. The divisome, on the other hand, is responsible for building the septal PG, and during cell division, the GTase FtsW plays a key role. Antagonistic activities are observed between the elongasome and the divisome, with the activity of one being repressed during the activity of the other.