CypA-CA interactions can affect many early steps of HIV-1 replication, disruption of the interaction between HIV-1 and CypA, either genetically or by cyclosporine A (CsA) addition, reduces the efficiency of HIV-1 infection (reviewed in [23]), and some studies have indicated that CypA-CA interactions influence nuclear entry [24,25], and more recently CypA has been shown to protect the HIV-1 CA from restriction by TRIM5⍺ [26,27]. Here, PPIA is linked to HIV-1 infection.