Contributors: Institut de biologie structurale (IBS - UMR 5075); Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG); Direction de Recherche Fondamentale (CEA) (DRF (CEA)); Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)); Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA); MICrobiologie de l'ALImentation au Service de la Santé (MICALIS); AgroParisTech-Université Paris-Saclay-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE); Microbiologie moléculaire et biochimie structurale - Molecular Microbiology and Structural Biochemistry (MMSB); Université Claude Bernard Lyon 1 (UCBL); Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS); Département de pharmacochimie moléculaire (DPM); Institut de Chimie - CNRS Chimie (INC-CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA); Laboratoire de microbiologie et génétique moléculaires - UMR5100 (LMGM); Centre de Biologie Intégrative (CBI); Université Toulouse III - Paul Sabatier (UT3); Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3); Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS); Groupe Pneumocoque (IBS-PG); Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG); Support for this work comes from the Agence Nationale de la Recherche (ANR-16-CE11-0016 and ANR-23-CE11-0029 to C.M., ANR-19-CE15-0011 to C.G., Labex ARCANE ANR-17-EURE-0003 to Y.S.W., and ANR-17-CE13-0031 to R.C.L. and N.C.), from the European Research Council (ERC) under the Horizon 2020 research and innovation program (grant agreement No 772178 to R.C.L.), and from a fellowship "Fin de thèse" of the Fondation pour la Recherche Médicale (FDT202204014744 to D.J.). This work used the platforms of the Grenoble Instruct-ERIC centre (ISBG; UMS 3518 CNRS-CEA-UGA-EMBL) within the Grenoble Partnership for Structural Biology (PSB), supported by FRISBI (ANR-10-INBS-05-02) and GRAL, financed within the University Grenoble Alpes graduate school (Ecoles Universitaires de Recherche) CBH-EUR-GS (ANR-17-EURE-0003). I.B.S. acknowledges integration into the Interdisciplinary Research Institute of Grenoble (IRIG, CEA).; ANR-16-CE11-0016,DIVinHD,Imagerie super-résolue de la division bactérienne(2016); ANR-23-CE11-0029,NanoWall,Analyse de la dynamique de synthèse et de maturation de la paroi cellulaire bactérienne à l'échelle nanométrique(2023); ANR-19-CE15-0011,LookingForPegase,A la recherche de protéines régulant des enzymes responsables de la synthèse du peptidoglycane(2019); ANR-17-CE13-0031,EXStasis,MECANISME DE L'ARRET DE CROISSANCE PROGRAMME PENDANT LA COMPETENCE POUR LA TRANSFORMATION CHEZ STREPTOCOCCUS PNEUMONIAE(2017); ANR-17-EURE-0003,CBH-EUR-GS,CBH-EUR-GS(2017)
نبذة مختصرة : International audience ; Bacterial shape and division rely on the dynamics of cell wall assembly, which involves regulated synthesis and cleavage of the peptidoglycan. In ovococci, these processes are coordinated within an annular mid-cell region with nanometric dimen sions. More precisely, the cross-wall synthesized by the divisome is split to generate a lateral wall, whose expansion is insured by the insertion of the so-called peripheral peptidoglycan by the elongasome. Septum cleavage and peripheral peptidoglycan synthesis are, thus, crucial remodeling events for ovococcal cell division and elongation. The structural DivIVA protein has long been known as a major regulator of these processes, but its mode of action remains unknown. Here, we integrate click chemis try-based peptidoglycan labeling, direct stochastic optical reconstruction microscopy, and in silico modeling, as well as epifluorescence and stimulated emission depletion microscopy to investigate the role of DivIVA in Streptococcus pneumoniae cell morpho genesis. Our work reveals two distinct phases of peptidoglycan remodeling during the cell cycle that are differentially controlled by DivIVA. In particular, we show that DivIVA ensures homogeneous septum cleavage and peripheral peptidoglycan synthesis around the division site and their maintenance throughout the cell cycle. Our data additionally suggest that DivIVA impacts the contribution of the elongasome and class A penicillin-binding proteins to cell elongation. We also report the position of DivIVA on either side of the septum, consistent with its known affinity for negatively curved membranes. Finally, we take the opportunity provided by these new observations to propose hypotheses for the mechanism of action of this key morphogenetic protein.
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