Fig. 3
A molecular handshake between TraA receptors governs cell–cell recognition. a A representative time series (45 s between frames) shows dynamic handshakes between a TraA-GFP cell and a TraA-mCherry cell. Fluorescence intensities at cell–cell contacts are quantified. Fluorescence was measured in arbitrary units (AU) throughout this study. b Representative images showing the colocalization of TraA-GFP and TraA-mCherry foci between two filamentous cells treated with cephalexin. Fluorescence intensity profiles along the entire cell–cell junction are shown below. c Self-contact of a filamentous TraA-mCherry cell caused foci formation. A single cell that tied a knot is shown (see Supplementary Fig. 5 for more examples). d TraA receptors cluster and colocalize (indicated with arrows) between cells harboring compatible traA alleles, whereas no clusters form between cells with incompatible alleles, i.e., DK1622 + Mf. e A merodiploid strain (indicated with dashed outlines) expressing both TraADK1622-mCherry and TraAMf-GFP selectively clusters its different receptors when encountering cognate unlabeled cells. Black borders and white arrows highlight specific recognition between the merodiploid strain and unlabeled social partners. Images shown in (c, d) represent the experimental observation of >100 cell–cell contacts in each mixing combination. See Supplementary Table 1 for strain details. Scale bar = 1 µm. Source data are provided as a Source Data file
