MOB1A and neoplasm: To define which MOB1 interactions with Hippo core kinases are necessary for tumor suppression, we engineered pools of MCF-7 human breast cancer cells stably expressing either empty vector (EV), HA-MOB1 wild-type (wt), HA-MOB1(D63V), HA-MOB1(K104E/K105E), or HA-MOB1(D63V/K104E/K105E) (Fig. 4a).