MAPK3 and cardiac hypertrophy: ERK and Akt signalling pathways are closely involved in cardiac hypertrophy and pulmonary vascular remodelling and oestrogen has been shown to regulate activation of Akt signalling in right heart failure.32,41 Additionally, selective activation of ERα in endothelial cells in aorta increases ERK expression and ERK1/2-mediated cell proliferation.