Repurposing of a DNA segregation machinery into a cytoskeletal system controlling cell shape
Summary
Bacteria, like eukaryotes, use conserved cytoskeletal systems for intracellular organization. The plasmid-encoded ParMRC system forms actin-like filaments that segregate low-copy number plasmids. In multicellular cyanobacteria such as Anabaena sp., we found that a chromosomally encoded ParMR system has evolved into a cytoskeletal system named CorMR with a function in cell shape control rather than DNA segregation. Live-cell imaging, in vitro reconstitution, and cryo-electron microscopy rev
Content
# Repurposing of a DNA segregation machinery into a cytoskeletal system controlling cell shape
*Published: 2026 Apr 16*
Bacteria, like eukaryotes, use conserved cytoskeletal systems for intracellular
organization. The plasmid-encoded ParMRC system forms actin-like filaments that
segregate low-copy number plasmids. In multicellular cyanobacteria such as
Anabaena sp., we found that a chromosomally encoded ParMR system has evolved
into a cytoskeletal system named CorMR with a function in cell shape control
rather than DNA segregation. Live-cell imaging, in vitro reconstitution, and
cryo-electron microscopy revealed that CorM formed dynamically unstable,
antiparallel double-stranded filaments that were recruited to the membrane by
CorR through an amphipathic helix conserved in multicellular cyanobacteria.
CorMR filaments were regulated by MinC, which excluded them from the poles and
division plane. Comparative genomics indicated that the repurposing of ParMR and
Min systems coevolved with cyanobacterial multicellularity, highlighting the
evolutionary plasticity of cytoskeletal systems in bacteria.
DOI: 10.1126/science.aea6343