Fig. 3.

FGFR4 suppresses MST1/2 activation and cleavage in HER2⁺ breast cancer cells. a, b MDA-MB-453 cells transfected with indicated siRNAs were subjected to immunoblotting for a T183/180 phosphorylated MST1/2, and b MST1 and MST2. Note cleaved ~ 37 kDa MST1/N in FGFR4 knockdown cells (arrowhead). Thin gray line indicates cropping to leave out irrelevant sample lane; see uncropped immunoblots in Fig. S8. c MDA-MB-453 cells transduced with indicated shRNAs were transfected with siScr or siFGFR4 siRNA to 3’UTR before transfection of mock or FGFR4 (R) or (G) overexpression plasmid for a rescue experiment. Lysates were subjected to immunoblotting as indicated. Brackets indicate the cleaved MST1 and MST2 fragments. See Fig. S2A for phopsho-FRS2α and short exposure of MST1. d MDA-MB-453 and ZR-75.1 cells were transduced with indicated si/shRNAs; upper, indicated immunoblots of lysates; lower, quantification of pMOB1/MOB1 ratio, N = 3, mean ± SEM; *P < 0.05. For MST1/2 knockdown e ZR-75.1 and f MDA-MB-453 were transduced with shRNAs followed by transfection with siRNAs as indicated, and g BT474 cells were transfected with indicated siRNAs, and subjected to immunoblotting for pT183/180 MST1/2, MST1, MST2, and pMOB1 as indicated (in e arrowhead points to a full-length, bracket to the cleaved MST2) a–g. N = 3 independent repeats for all; except N = 2 in f and g