title: Interaction of Penicillin-Binding Protein 2x and Ser/Thr protein kinase StkP, two key players in Streptococcus pneumoniae R6 morphogenesis.
abstract: Bacterial cell growth and division require the co-ordinated action of peptidoglycan biosynthetic enzymes and cell morphogenesis proteins. However, the regulatory mechanisms that allow generating proper bacterial shape and thus preserving cell integrity remain largely uncharacterized, especially in ovococci. Recently, the conserved eukaryotic-like Ser/Thr protein kinase of Streptococcus pneumoniae (StkP) was demonstrated to play a major role in cell shape and division. Here, we investigate the molecular mechanisms underlying the regulatory function(s) of StkP and show that it involves one of the essential actors of septal peptidoglycan synthesis, Penicillin-Binding Protein 2x (PBP2x). We demonstrate that StkP and PBP2x interact directly and are present in the same membrane-associated complex in S. pneumoniae. We further show that they both display a late-division localization pattern at the division site and that the positioning of PBP2x depends on the presence of the extracellular PASTA domains of StkP. We demonstrate that StkP and PBP2x interaction is mediated by their extracellular regions and that the complex formation is inhibited in vitro in the presence of cell wall fragments. These data suggest that the role of StkP in cell division is modulated by an interaction with PBP2x.
authors.affiliation: Univ. Grenoble Alpes, IBS, F-38027, Grenoble, France; CNRS, IBS, F-38027, Grenoble, France; CEA, IBS, Institut de Biologie Structurale, Pneumococcus Group, F-38027, Grenoble, France.
authors.forename: C
authors.initials: C
authors.lastname: Morlot
authors.forename: L
authors.initials: L
authors.lastname: Bayle
authors.forename: M
authors.initials: M
authors.lastname: Jacq
authors.forename: A
authors.initials: A
authors.lastname: Fleurie
authors.forename: G
authors.initials: G
authors.lastname: Tourcier
authors.forename: F
authors.initials: F
authors.lastname: Galisson
authors.forename: T
authors.initials: T
authors.lastname: Vernet
authors.forename: C
authors.initials: C
authors.lastname: Grangeasse
authors.forename: A M
authors.initials: AM
authors.lastname: Di Guilmi
mesh_terms: D002473:Cell Wall / Q000201:enzymology / Q000378:metabolism; D046915:Penicillin-Binding Proteins / Q000378:metabolism*; D011485:Protein Binding; D025941:Protein Interaction Mapping; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D013296:Streptococcus pneumoniae / Q000201:enzymology* / Q000254:growth & development*
chemical_list: D046915:Penicillin-Binding Proteins; C072223:PBP 2x protein, Streptococcus; D017346:Protein Serine-Threonine Kinases