Cytoplasmic contractile injection systems mediate cell death in Streptomyces.

Contractile injection systems (CIS) are bacteriophage tail-like structures that mediate bacterial cell-cell interactions. While CIS are highly abundant across diverse bacterial phyla, representative gene clusters in Gram-positive organisms remain poorly studied. Here we characterize a CIS in the Gram-positive multicellular model organism Streptomyces coelicolor and show that, in contrast to most other CIS, S.

Cap-tivating findings provide insight into bacterial cell division.

In most bacteria, cell division is orchestrated by the tubulin homolog FtsZ. To ensure the correct placement of the division machinery, FtsZ activity needs to be tightly regulated. Corrales-Guerrero et al.

A conserved cell division protein directly regulates FtsZ dynamics in filamentous and unicellular actinobacteria.

Bacterial cell division is driven by the polymerization of the GTPase FtsZ into a contractile structure, the so-called Z-ring. This essential process involves proteins that modulate FtsZ dynamics and hence the overall Z-ring architecture. Actinobacteria like and lack known key FtsZ-regulators.