Purity ≥98%. MW: 416.47. XMU-MP-1 is a potent and selective ATP-competitive mammalian sterile 20-like kinase (MST) 1/2 inhibitor (IC50 values are 38.1 and 71.1 nM for MST2 and MST1, respectively). It is selective for MST1 and 2 over a panel of 468 kinases at a concentration of 1 μM. XMU-MP-1 inhibits phosphorylation of MOB1, LATS1 and 2, and YAP in HepG2 cells as well as MST1 and 2 autophosphorylation in RAW 264.7, U2OS, SW480, RPE1, SNU423, and HepG2 cells in a concentration-dependent manner. Enhances activity of downstream YAP in vitro.