Fig 4. PBP4 is recruited by the septal cleavage complex FtsEX.

(A) Cells of BW25113 expressing the proteins indicated were grown in LB at 37°C to OD₆₀₀ = 0.3, fixed and labeled with specific antibodies against PBP4. From left to right, the phase contrast, corresponding fluorescence image of the PBP4 labeling, and the merged former two images, demograph of fluorescence with the cell lengths outlined (with the same contrast and brightness) for all demographs of PBP4 localization where cells are sorted according to their cell length are shown. The number of cells analyzed were 687 for ΔenvC, 434 for ΔftsE, and 346 for ΔftsEX. The scale bar equals 5 μm. (B) Cells of LMC500 or XL36 (LMC500ΔftsE::pTrc99Adown ftsX) expressing wild-type or active site versions of FtsE were immunolabeled with anti-PBP4 antibodies. Cells were grown in TY at 30°C and FtsE expression from plasmid was induced for 2 mass doubling with 30 μM IPTG, and cell were fixed and harvested at an OD₆₀₀ of 0.3. The demographs of PBP4 fluorescence with the cell lengths outlined is shown for the indicated strains. Number of cells analyzed: LMC500 (2462), wild-type (2588), K41Q (728), D162A (554), and E163E (1052).