TY - JOUR TI - Modularity and determinants of a (bi-)polarization control system from free-living and obligate intracellular bacteria AU - Bergé, Matthieu AU - Campagne, Sébastien AU - Mignolet, Johann AU - Holden, Seamus AU - Théraulaz, Laurence AU - Manley, Suliana AU - Allain, Frédéric H-T AU - Viollier, Patrick H A2 - Veening, Jan Willem VL - 5 PY - 2016 DA - 2016/12/23 SP - e20640 C1 - eLife 2016;5:e20640 DO - 10.7554/eLife.20640 UR - https://doi.org/10.7554/eLife.20640 AB - Although free-living and obligate intracellular bacteria are both polarized it is unclear whether the underlying polarization mechanisms and effector proteins are conserved. Here we dissect at the cytological, functional and structural level a conserved polarization module from the free living α-proteobacterium Caulobacter crescentus and an orthologous system from an obligate intracellular (rickettsial) pathogen. The NMR solution structure of the zinc-finger (ZnR) domain from the bifunctional and bipolar ZitP pilus assembly/motility regulator revealed conserved interaction determinants for PopZ, a bipolar matrix protein that anchors the ParB centromere-binding protein and other regulatory factors at the poles. We show that ZitP regulates cytokinesis and the localization of ParB and PopZ, targeting PopZ independently of the previously known binding sites for its client proteins. Through heterologous localization assays with rickettsial ZitP and PopZ orthologs, we document the shared ancestries, activities and structural determinants of a (bi-)polarization system encoded in free-living and obligate intracellular α-proteobacteria. KW - Caulobacter crescentus KW - Rickettsia massiliae KW - Rhodobacter sphaeroides KW - polarity KW - PopZ KW - ZitP JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -