Wenyan Zhang, Jianwei Chen, Jie Dai, Shiwei Zhu, Hugo Le Guenno, Artemis Kosta, Hongmiao Pan, Xin-Xin Qian, Claire-Lise Santini, Nicolas Menguy, Xuegong Li, Yiran Chen, Jia Liu, Kaixuan Cui, Yicong Zhao, Guilin Liu, Eric Durand, Wei-Jia Zhang, Alain Roussel, Tian Xiao, Long-Fei Wu, Helmholtz-Zentrum Geesthacht (GKSS), Ming Hsieh Department of Electrical Engineering [Los Angeles], USC Viterbi School of Engineering, University of Southern California (USC)-University of Southern California (USC), Research Center for Proteome Analysis Key Lab of Proteomics, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Chinese Academy of Sciences [Beijing] (CAS), Yale School of Medicine [New Haven, Connecticut] (YSM), Centre d'Immunologie de Marseille - Luminy (CIML), Aix Marseille Université (AMU)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), CAS Key Laboratory of Marine Ecology and Environmental Science (KLMEES), CAS Institute of Oceanology (IOCAS), Chinese Academy of Sciences [Beijing] (CAS)-Chinese Academy of Sciences [Beijing] (CAS), Laboratoire de chimie bactérienne (LCB), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de recherche pour le développement [IRD] : UR206-Centre National de la Recherche Scientifique (CNRS), International Associated Laboratory of Evolution and Development of Magnetotactic Multicellular Organisms ( LIA-MagMC), Chinese Academy of Sciences [Beijing] (CAS)-Centre National de la Recherche Scientifique (CNRS), Xi'an Jiaotong University (Xjtu), Endothélium, valvulopathies et insuffisance cardiaque (EnVI), Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Normandie Université (NU)-Institut National de la Santé et de la Recherche Médicale (INSERM), Architecture et fonction des macromolécules biologiques (AFMB), and Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)
Endosomal sorting complex required transport (ESCRT) III proteins are essential for membrane remodeling and repair across all domains of life. Eukaryotic ESCRT-III and the cyanobacterial homologs PspA and Vipp1/Imm30 remodel membrane into vesicles, rings, filaments and tubular rods structures. Here our microscopy analysis showed that multicellular bacteria, referred to as magnetoglobules, possess multiple compartments including magnetosome organelles, polyphosphate granules, vesicles, rings, tubular rods, filaments and MVB-like structures. Therefore, membrane remodeling protein PspA might be required for the formation of these compartments, and contribute to the morphogenesis and evolution of multicellularity. To assess these hypotheses, we sequenced nine genomes of magnetoglobules and found a significant genome expansion compared to unicellular magnetotactic bacteria. Moreover, PspA was ubiquitous in magnetoglobules and formed a distinct clade on the tree of eubacterial and archaeal ESCRT-III. The phylogenetic feature suggested the evolution of magnetoglobules from a unicellular ancestor of deltaproteobacterium. Hetero-expression of ellipsoidal magnetoglobulepspA2gene alone inEscherichia coliresulted in intracellular membrane aggregation. GFP fusion labeling revealed polar location of PspA2 in rod-shaped unicells and regular interval location in filamentous cells. Cryo-electron tomography analysis showed filament bundle, membrane sacculus, vesicles and MVB-like structure in the cells expressing PspA2. Moreover, electron-dense area with a similar distribution as GFP-PspA2 foci in filamentous cells changed the inward orientation of the septum, which might interfere with the cell division. Collectively, these results show the membrane remodeling function of magnetoglobule PspA proteins, which may contribute to morphogenesis and the evolution of multicellularity of magnetotactic bacteria.