Temel Kavramlar
Aeg1 is a previously unrecognized core component of the Acinetobacter baumannii divisome that interacts with multiple cell division proteins, including FtsN, to recruit and activate the septal peptidoglycan synthase FtsWI.
Özet
The content describes the identification and characterization of Aeg1, a previously unrecognized essential cell division protein in the pathogenic bacterium Acinetobacter baumannii. Key highlights:
Using a conditional gene deletion method, the authors identified three previously annotated "hypothetical" genes, including aeg1 (A1S_3387), as essential for A. baumannii viability on rich medium.
Depletion of Aeg1 caused cell elongation, a phenotype associated with defects in cell division. Suppressor mutations that bypassed the requirement of Aeg1 mapped to the cell division gene ftsA, suggesting Aeg1 participates in the cell division process.
The authors demonstrated that Aeg1 interacts with multiple core divisome proteins, including ZipA, FtsK, FtsL, FtsB, and FtsN. Aeg1 colocalized with these divisome proteins at the division site.
Depletion of Aeg1 prevented the localization of these divisome proteins to the midcell, indicating Aeg1 is required for their proper recruitment.
Constitutively active mutants of FtsB, FtsL, and FtsW were able to bypass the need for Aeg1, suggesting Aeg1 functions upstream of these proteins to activate the septal peptidoglycan synthase FtsWI.
The authors propose a model in which Aeg1 acts as a scaffold to recruit FtsN, which in turn activates the FtsQLB complex and FtsA to induce the septal peptidoglycan synthesis by FtsWI, thereby playing a critical role in the assembly of the bacterial divisome.
İstatistikler
Depletion of Aeg1 caused more than 96% of A. baumannii cells to become elongated with cell lengths ranging from 5 μm to over 10 μm.
Expression of the FtsAE202K mutant allowed the Δaeg1 strain to grow in the absence of Aeg1, while wild-type FtsA could not.
Aeg1 interacted strongly with ZipA and FtsN in the bacterial two-hybrid assay.
Expression of the FtsBE65A, FtsLQ70K, FtsWM254I, and FtsWS274G mutants bypassed the requirement of Aeg1 in A. baumannii.
Alıntılar
"Aeg1 is a cell division protein that arrives at the division site to initiate cell division by recruiting FtsN, which activates FtsQLB and FtsA to induce the septal peptidoglycan synthase FtsWI."
"The discovery of the new essential cell division protein has provided a new target for the development of antibacterial agents."