Fig. 1

FGFR4 substrate screen identifies tyrosine-phosphorylated Hippo pathway proteins including MST1/2. a Scheme of the substrate screen with recombinant FGFR4 kinase domain. b Top 10 FGFR4 substrates ranked by the Z-score include Hippo pathway -associated proteins (yellow). See Table S1 for the full substrate list. c, d MST1/2 are tyrosine phosphorylated by FGFR4 in COS-1 cells. Flag-tagged MST1/2 were immunoprecipitated after transfection of MST1 and MST2 alone or in combination with FGFR4 G388 (G), or R388 (R) kinase (wt), or kinase-dead (KD) variants, and detected by immunoblotting. e MST1 immunoprecipitates from COS-1 cells co-transfected with FGFR4 (R)-wt or FGFR4 (R)-KD (See Fig. S1A) were trypsin digested and subjected to phoshopeptide enrichment prior to LC-MS/MS analysis (N = 3) that identified phosphorylated Y433 (red) on MST1 only with FGFR4 (R)-wt, and phosphorylated S410 (green) only with FGFR4 (R)-KD