CAPN1 and infection: Furthermore, based on previous studies that reported an important role for calpain 1 in infection, intracellular trafficking and uncoating of echovirus 1, coxsackievirus, human immunodeficiency virus type 1, hepatitis C virus and herpes simplex virus type 1 (Upla et al., 2008; Bozym et al., 2010; Zheng et al., 2014), we focused on calpain 1 for further studies and found that inhibition of calpain 1 strongly suppressed viral replication in both MARC-145 cells and PAMs (Figure 7).