Roles of pneumococcal DivIB in cell division. - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Bacteriology Année : 2008

Roles of pneumococcal DivIB in cell division.

Audrey Le Gouellec
Daniela Fadda
  • Fonction : Auteur
Orietta Massidda
  • Fonction : Auteur
Thierry Vernet
André Zapun

Résumé

DivIB, also known as FtsQ in gram-negative organisms, is a division protein that is conserved in most eubacteria. DivIB is localized at the division site and forms a complex with two other division proteins, FtsL and DivIC/FtsB. The precise function of these three bitopic membrane proteins, which are central to the division process, remains unknown. We report here the characterization of a divIB deletion mutant of Streptococcus pneumoniae, which is a coccus that divides with parallel planes. Unlike its homologue FtsQ in Escherichia coli, pneumococcal DivIB is not required for growth in rich medium, but the Delta divIB mutant forms chains of diplococci and a small fraction of enlarged cells with defective septa. However, the deletion mutant does not grow in a chemically defined medium. In the absence of DivIB and protein synthesis, the partner FtsL is rapidly degraded, whereas other division proteins are not affected, pointing to a role of DivIB in stabilizing FtsL. This is further supported by the finding that an additional copy of ftsL restores growth of the Delta divIB mutant in defined medium. Functional mapping of the three distinct alpha, beta, and gamma domains of the extracellular region of DivIB revealed that a complete beta domain is required to fully rescue the deletion mutant. DivIB with a truncated beta domain reverts only the chaining phenotype, indicating that DivIB has distinct roles early and late in the division process. Most importantly, the deletion of divIB increases the susceptibility to beta-lactams, more evidently in a resistant strain, suggesting a function in cell wall synthesis.
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Dates et versions

hal-01464088 , version 1 (09-02-2017)

Identifiants

  • HAL Id : hal-01464088 , version 1
  • PUBMED : 18441058

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Audrey Le Gouellec, Laure Roux, Daniela Fadda, Orietta Massidda, Thierry Vernet, et al.. Roles of pneumococcal DivIB in cell division.. Journal of Bacteriology, 2008, pp.4501-11. ⟨hal-01464088⟩
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