MAPK1 and viral infectious disease: This signaling pathway has been shown to play an important role in viral infections, such as HCV (which increases the activity of p38 MAPK pathway), HIV (which upregulates the ERK activation) (Gaur et al., 2011) or cytomegalovirus (which, by increasing the activity of MAP2K3, maintains p38 active for viral replication) (Johnson et al., 2000).