MAPK3 and cardiac hypertrophy: To further investigate potential roles of the ERK1/2 and AKT pathways in inhibiting HF by XML, we analyzed a down-stream target, GATA4, which is a zinc finger containing transcription factor that plays key roles in promoting heart growth and regulating cardiac hypertrophy and heart failure11, 12, and is associated with multiple hypertrophic signaling pathways, such as ERK1/213, p3814, AKT15, and CnA/NFATc316.