title: Roles of Capsid-Interacting Host Factors in Multimodal Inhibition of HIV-1 by PF74.
abstract: The viral capsid of HIV-1 interacts with a number of host factors to orchestrate uncoating and regulate downstream events, such as reverse transcription, nuclear entry, and integration site targeting. PF-3450074 (PF74), an HIV-1 capsid-targeting low-molecular-weight antiviral compound, directly binds to the capsid (CA) protein at a site also utilized by host cell proteins CPSF6 and NUP153. Here, we found that the dose-response curve of PF74 is triphasic, consisting of a plateau and two inhibitory phases of different slope values, consistent with a bimodal mechanism of drug action. High PF74 concentrations yielded a steep curve with the highest slope value among different classes of known antiretrovirals, suggesting a dose-dependent, cooperative mechanism of action. CA interactions with both CPSF6 and cyclophilin A (CypA) were essential for the unique dose-response curve. A shift of the steep curve at lower drug concentrations upon blocking the CA-CypA interaction suggests a protective role for CypA against high concentrations of PF74. These findings, highlighting the unique characteristics of PF74, provide a model in which its multimodal mechanism of action of both noncooperative and cooperative inhibition by PF74 is regulated by interactions of cellular proteins with incoming viral capsids.
  
  
  
  PF74, a novel capsid-targeting antiviral against HIV-1, shares its binding site in the viral capsid protein (CA) with the host factors CPSF6 and NUP153. This work reveals that the dose-response curve of PF74 consists of two distinct inhibitory phases that are differentially regulated by CA-interacting host proteins. PF74's potency depended on these CA-binding factors at low doses. In contrast, the antiviral activity of high PF74 concentrations was attenuated by cyclophilin A. These observations provide novel insights into both the mechanism of action of PF74 and the roles of host factors during the early steps of HIV-1 infection.
authors.affiliation: Aaron Diamond AIDS Research Center, New York, New York, USA.
authors.forename: Akatsuki
authors.initials: A
authors.lastname: Saito
authors.affiliation: Aaron Diamond AIDS Research Center, New York, New York, USA.
authors.forename: Damien
authors.initials: D
authors.lastname: Ferhadian
authors.affiliation: Dana Farber Cancer Institute, Department of Cancer Immunology and Virology, Boston, Massachusetts, USA.
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Sowd
authors.affiliation: Dana Farber Cancer Institute, Department of Cancer Immunology and Virology, Boston, Massachusetts, USA.
authors.forename: Erik
authors.initials: E
authors.lastname: Serrao
authors.affiliation: Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA.
authors.forename: Jiong
authors.initials: J
authors.lastname: Shi
authors.affiliation: Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA.
authors.forename: Upul D
authors.initials: UD
authors.lastname: Halambage
authors.affiliation: Aaron Diamond AIDS Research Center, New York, New York, USA.
authors.forename: Samantha
authors.initials: S
authors.lastname: Teng
authors.affiliation: Aaron Diamond AIDS Research Center, New York, New York, USA.
authors.forename: Juan
authors.initials: J
authors.lastname: Soto
authors.affiliation: Aaron Diamond AIDS Research Center, New York, New York, USA.
authors.forename: Mohammad Adnan
authors.initials: MA
authors.lastname: Siddiqui
authors.affiliation: Dana Farber Cancer Institute, Department of Cancer Immunology and Virology, Boston, Massachusetts, USA.
authors.forename: Alan N
authors.initials: AN
authors.lastname: Engelman
authors.affiliation: Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Aiken
authors.affiliation: Aaron Diamond AIDS Research Center, New York, New York, USA myamashi@adarc.org.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yamashita
mesh_terms: D019380:Anti-HIV Agents / Q000494:pharmacology*; D001665:Binding Sites; D002213:Capsid / Q000187:drug effects / Q000378:metabolism*; D036022:Capsid Proteins / Q000378:metabolism; D021984:Cyclophilin A / Q000378:metabolism / Q000494:pharmacology; D057809:HEK293 Cells; D015497:HIV-1 / Q000187:drug effects* / Q000502:physiology; D006367:HeLa Cells; D054884:Host-Pathogen Interactions; D006801:Humans; D007211:Indoles / Q000494:pharmacology*; D028861:Nuclear Pore Complex Proteins / Q000235:genetics / Q000378:metabolism*; D010649:Phenylalanine / Q000031:analogs & derivatives* / Q000494:pharmacology; D048348:Reverse Transcription / Q000187:drug effects; D014779:Virus Replication / Q000187:drug effects; D039221:mRNA Cleavage and Polyadenylation Factors / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*
chemical_list: D019380:Anti-HIV Agents; D036022:Capsid Proteins; D007211:Indoles; C079377:NUP153 protein, human; D028861:Nuclear Pore Complex Proteins; C000591221:PF-3450074; C450562:cleavage factor Im, human; D039221:mRNA Cleavage and Polyadenylation Factors; D010649:Phenylalanine; D021984:Cyclophilin A