PPIA and HIV-1 infection: Disruption of CYPA binding either by CYPA knock-out (as demonstrated previously [2,3] and shown above), mutation of the capsid (i.e., through a capsid P90A mutation), or through treatment with the CYPA inhibitor cyclosporin A (CsA) decreases HIV-1 infection due to TRIM5α-mediated restriction (Fig 4c).