Fig. 2: Selectivity of BG towards TGF-β family ligands.

a Confocal microscopy images of HEK293T cells stably transfected with a SNAP-tagged BG construct (SNAP-BG) stained with DAPI (left panels, blue), incubated with SNAP-tag ligand conjugated to the CF567 fluorescent dye (middle panels, red), along with TGF-β2 tagged with AF647 fluorescent dye (right panels, violet) alone (row 1) or with the addition of an excess of indicated unlabeled ligands (rows 2–7). Scale bar, 50 µm. b Quantification of the fluorescent colocalized SNAP-BG/TGF-β2 microscopy data. Each data point represents the ratio of SNAP-BG signal to TGF-β2 signal within a segmented region of the image generated by applying the Otsu thresholding method to the SNAP-BG channel. Analysis was performed on three images per condition, each corresponding to an independent biological replicate (n = 3). AF2M analysis for ratBGO (c) and BGZP-C (d) complex formation capability with selected ligands. The y-axis represents the iptm+ptm score mean values with standard deviation derived from a total of 25 models generated for each complex. GF, growth factor. Source data are provided as a Source Data file.