PPIA and infection: Two of these mIMRs terminate within capsid D235..E260 which is a region of small helices and loops adjacent to the CypA binding site that is probably essential to disassembling the core upon infection [14]; these mIMRs, then, begin at sequences that localize Gag to the cell membrane – a process essential to core formation – and end at sequences that dissolve the virion core (upon infection).