GCN2 activator-1 (Compound 20) is a GCN2 activator. GCN2 activator-1 binds within the ATP-pocket of GCN2 and activates GCN2 in a GCN1-independent manner. GCN2 activator-1 activates Integrated Stress Response (ISR) in cells. GCN2 activator-1 inhibits PKR with an IC50 of 3.75 µM. GCN2 activator-1 can be used for research of pulmonary veno-occlusive disease (PVOD)[1].