title: Cyclophilin A renders human immunodeficiency virus type 1 sensitive to Old World monkey but not human TRIM5 alpha antiviral activity.
abstract: TRIM5alpha is an important mediator of antiretroviral innate immunity influencing species-specific retroviral replication. Here we investigate the role of the peptidyl prolyl isomerase enzyme cyclophilin A in TRIM5alpha antiviral activity. Cyclophilin A is recruited into nascent human immunodeficiency virus type 1 (HIV-1) virions as well as incoming HIV-1 capsids, where it isomerizes an exposed proline residue. Here we show that cyclophilin A renders HIV-1 sensitive to restriction by TRIM5alpha in cells from Old World monkeys, African green monkey and rhesus macaque. Inhibition of cyclophilin A activity with cyclosporine A, or reducing cyclophilin A expression with small interfering RNA, rescues TRIM5alpha-restricted HIV-1 infectivity. The effect of cyclosporine A on HIV-1 infectivity is dependent on TRIM5alpha expression, and expression of simian TRIM5alpha in permissive feline cells renders them able to restrict HIV-1 in a cyclosporine A-sensitive way. We use an HIV-1 cyclophilin A binding mutant (CA G89V) to show that cyclophilin A has different roles in restriction by Old World monkey TRIM5alpha and owl monkey TRIM-Cyp. TRIM-Cyp, but not TRIM5alpha, recruits its tripartite motif to HIV-1 capsid via cyclophilin A and, therefore, HIV-1 G89V is insensitive to TRIM-Cyp but sensitive to TRIM5alpha. We propose that cyclophilin A isomerization of a proline residue in the TRIM5alpha sensitivity determinant of the HIV-1 capsid sensitizes it to restriction by Old World monkey TRIM5alpha. In humans, where HIV-1 has adapted to bypass TRIM5alpha activity, the effects of cyclosporine A are independent of TRIM5alpha. We speculate that cyclophilin A alters HIV-1 sensitivity to a TRIM5alpha-independent innate immune pathway in human cells.
authors.affiliation: Department of Infection, Royal Free and University College Medical School, University College London, Windeyer Building, 46 Cleveland Street, London W1T4JF, United Kingdom.
authors.forename: Zuzana
authors.initials: Z
authors.lastname: Keckesova
authors.forename: Laura M J
authors.initials: LM
authors.lastname: Ylinen
authors.forename: Greg J
authors.initials: GJ
authors.lastname: Towers
mesh_terms: D000818:Animals; D019380:Anti-HIV Agents / Q000494:pharmacology*; D000090103:Antiviral Restriction Factors; D002352:Carrier Proteins / Q000494:pharmacology*; D002415:Cats; D002460:Cell Line; D002520:Cercopithecidae; D021984:Cyclophilin A / Q000494:pharmacology*; D016572:Cyclosporine / Q000494:pharmacology; D024882:Drug Resistance, Viral / Q000187:drug effects; D015658:HIV Infections / Q000188:drug therapy; D015497:HIV-1 / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D009052:Leukemia Virus, Murine / Q000378:metabolism; D015302:Simian Immunodeficiency Virus / Q000378:metabolism; D000070584:Tripartite Motif Proteins; D044767:Ubiquitin-Protein Ligases
chemical_list: D019380:Anti-HIV Agents; D000090103:Antiviral Restriction Factors; D002352:Carrier Proteins; D000070584:Tripartite Motif Proteins; D016572:Cyclosporine; C477346:TRIM5 protein, human; D044767:Ubiquitin-Protein Ligases; D021984:Cyclophilin A