Fig. 1

FGFR expression and phosphorylation signature in TNBC cell lines as determined by MS-based tyrosine phosphorylation profiling. a, Relative normalized abundance of FGFR1–4 phosphorylated tyrosine (pY) residues based on z-score across a panel of 24 TNBC cell lines. The z-scores of detectable tyrosine-phosphosites were obtained by subtracting the mean of all pY sites across the 24 TNBC cell line panel from the value for the pY site, and then dividing by the standard deviation of all 24 TNBC cell lines. The white box represents a non-detectable pY site. The asterisks indicate that FGFR3_Y599 is identical to FGFR1 (Y605) while FGFR3_Y607 is identical to FGFR2 (Y616), but the FGFR3 assignment is more likely given relative receptor expression levels. b, Characterization of FGFR1–4 expression in a panel of 11 TNBC cell lines. Cell lysates were Western blotted as indicated. Arrow indicates FGFR3-TACC3 fusion protein, bracket indicates wildtype FGFR3. c, Schematic of FGFR3-TACC3 fusion protein adapted from Shaver et al. (2016). The protein structure of wildtype FGFR3 is shown in pink and wildtype TACC3 is shown in blue. The grey dotted lines highlight the junction between FGFR3 and TACC3, which forms the FGFR3-TACC3 fusion protein in the SUM185PE cell line. FW FGFR3 antibody detects the region of FGFR3 between amino acids 25–124, recognising both wildtype FGFR3 and the FGFR3-TACC3 fusion protein. Wildtype FGFR3 antibody detects FGFR3 at the C-terminal region, only recognising wildtype FGFR3. TM = transmembrane