Interaction of Penicillin‐Binding Protein 2x and Ser/Thr protein kinase StkP, two key players in Streptococcus pneumoniae R6 morphogenesis

Abstract

SummaryBacterial 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, PenicillinBinding 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 latedivision 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.

Biological and Epidemiological Features of Antibiotic-Resistant Streptococcus pneumoniae in Pre- and Post-Conjugate Vaccine Eras: a United States Perspective

“…A missense mutation within the pdgA-encoded peptidoglycan N-acetylglucosamine deacetylase (130) was involved in a late transformational step in achieving high-level penicillin resistance in PBP experiments employing donor chromosomal DNA from a highly penicillin-resistant pneumococcal strain. StkP (Ser/Thr kinase) is involved in pneumococcal cell division (131) and has been shown to colocalize with PBP2x at the cell division site (132). Inactivation of stkP in a penicillin-resistant clinical isolate with altered PBPs abrogated penicillin resistance; however, a survey of penicillin-resistant isolates revealed no altered stkP alleles (133).…”

The PASTA domain of penicillin-binding protein SpoVD is dispensable for endospore cortex peptidoglycan assembly in Bacillus subtilis

“…What would be the importance of peptidoglycan interaction with a PASTA domain? So far, two different roles have been suggested for such interaction: (i) localization of the protein to the site of active peptidoglycan synthesis (Mir et al, 2011;Morlot et al, 2013), and (ii) activation of a novel endospore germination pathway in response to peptidoglycan fragments (Shah et al, 2008).…”

Growth- and Stress-Induced PASTA Kinase Phosphorylation in Enterococcus faecalis

“…PASTA kinases are ubiquitous among Actinobacteria and Firmicutes and regulate critical processes, including antibiotic resistance, cell division, toxin production, and virulence, and they are even essential for viability in certain organisms (6,(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29). However, the molecular signals that are directly sensed by PASTA kinases and the mechanisms by which those signals are processed, integrated, and converted into coordinated adaptive biological responses in vivo are poorly understood.…”