A CTP-binding protein links the ParABS chromosome segregation system to the bactofilin cytoskeleton in Myxococcus xanthus

Bactoflins are a new class of bacteria-specific cytoskeletal elements that polymerize spontaneously in the absence of additional cofactors. Bactofilins are widespread among bacteria and participate in diverse functions in different bacterial species, such as cell shape maintenance, cell wall stability, and motility.
We have recently characterized a new role of bactofilins in chromosome segregation in Myxococcus xanthus, where bactofilins BacNOP co-assemble into elongated scaffolds at the cell poles that immobilize the ParAB chromosome segregation machinery. The centromere-binding protein ParB associates to the pole-distal ends of these structures, whereas the partitioning ATPase ParA binds along their entire length via the CTP-binding protein PadC. Mutations in the CTP binding pocket of PadC disrupt ParA recruitment to the cell poles, a possible role of CTP will be discussed.