The D,D-carboxypeptidase PBP3 organizes the division process of Streptococcus pneumoniae.
Bacterial division requires the co-ordination of membrane invagination, driven by the constriction of the FtsZ-ring, and concomitant cell wall synthesis, performed by the high-molecular-weight penicillin-binding proteins (HMW PBPs). Using immunofluorescence techniques, we show in Streptococcus pneumoniae that this co-ordination requires PBP3, a D,D-carboxypeptidase that degrades the substrate of the HMW PBPs. In a mutant deprived of PBP3, the apparent rings of HMW PBPs and that of FtsZ are no longer co-localized. In wild-type cells, PBP3 is absent at the future division site and present over the rest of the cell surface, implying that the localization of the HMW PBPs at mid-cell depends on the availability of their substrate. FtsW, a putative translocase of the substrate of the PBPs, forms an apparent ring that is co-localized with the septal HMW PBPs throughout the cell cycle of wild-type cells. In particular, the constriction of the FtsW-ring occurs after that of the FtsZ-ring, with the same delay as the constriction of the septal PBP-rings. However, in the absence of PBP3, FtsW remains co-localized with FtsZ in contrast to the HMW PBPs. Our work reveals an unexpected complexity in the relationships between the division proteins. The consequences of the absence of PBP3 indicate that the peptidoglycan composition is central to the co-ordination of the division process.
Laboratoire d'Ingénierie des Macromolécules, Institut de Biologie Structurale J-P Ebel (CEA/CNRS/UJF, UMR 5075), 41 rue Jules Horowitz, 38027 Grenoble Cedex 1, France.
Cécile
C
Morlot
Marjolaine
M
Noirclerc-Savoye
André
A
Zapun
Otto
O
Dideberg
Thierry
T
Vernet
D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000378:metabolism; D002455:Cell Division; D003598:Cytoskeletal Proteins / Q000235:genetics* / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D006602:Hexosyltransferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D002267:Muramoylpentapeptide Carboxypeptidase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D046915:Penicillin-Binding Proteins; D010457:Peptidoglycan / Q000378:metabolism; D010458:Peptidyl Transferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport; D013296:Streptococcus pneumoniae / Q000166:cytology / Q000201:enzymology* / Q000235:genetics / Q000502:physiology*
D001426:Bacterial Proteins; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D003598:Cytoskeletal Proteins; C071525:FtsZ protein, Bacteria; D008565:Membrane Proteins; D046915:Penicillin-Binding Proteins; D010457:Peptidoglycan; C061684:FtsW protein, Bacteria; D010458:Peptidyl Transferases; D006602:Hexosyltransferases; D002267:Muramoylpentapeptide Carboxypeptidase