Figure 3. Loss of MST in PAX3-FOXO1-aRMS inhibits non-canonical Hippo signaling.

(A) IHC of tumors from MST^WT and MST^Null mice both show strong nuclear YAP1 staining, suggesting that loss of MST1 and MST2 in the MST^Null group is not impacting canonical Hippo signaling, in accord with the immunoblot of Hippo pathway proteins shown in Fig.2A. Representative images shown. (B) Immunofluorescence of tumor-derived cell lines from both MST^WT and MST^Null groups show strong nuclear YAP1 staining. Scale bar: 50µm. (C) Immunoblots of fractionated cell lysates of tumor-derived cell lines show YAP1 in the nuclear but not cytoplasmic fraction, independent of cell density.