title: Small molecules targeted to a non-catalytic "RVxF" binding site of protein phosphatase-1 inhibit HIV-1.
abstract: HIV-1 Tat protein recruits host cell factors including CDK9/cyclin T1 to HIV-1 TAR RNA and thereby induces HIV-1 transcription. An interaction with host Ser/Thr protein phosphatase-1 (PP1) is critical for this function of Tat. PP1 binds to a Tat sequence, Q(35)VCF(38), which resembles the PP1-binding "RVxF" motif present on PP1-binding regulatory subunits. We showed that expression of PP1 binding peptide, a central domain of Nuclear Inhibitor of PP1, disrupted the interaction of HIV-1 Tat with PP1 and inhibited HIV-1 transcription and replication. Here, we report small molecule compounds that target the "RVxF"-binding cavity of PP1 to disrupt the interaction of PP1 with Tat and inhibit HIV-1 replication. Using the crystal structure of PP1, we virtually screened 300,000 compounds and identified 262 small molecules that were predicted to bind the "RVxF"-accommodating cavity of PP1. These compounds were then assayed for inhibition of HIV-1 transcription in CEM T cells. One of the compounds, 1H4, inhibited HIV-1 transcription and replication at non-cytotoxic concentrations. 1H4 prevented PP1-mediated dephosphorylation of a substrate peptide containing an RVxF sequence in vitro. 1H4 also disrupted the association of PP1 with Tat in cultured cells without having an effect on the interaction of PP1 with the cellular regulators, NIPP1 and PNUTS, or on the cellular proteome. Finally, 1H4 prevented the translocation of PP1 to the nucleus. Taken together, our study shows that HIV- inhibition can be achieved through using small molecules to target a non-catalytic site of PP1. This proof-of-principle study can serve as a starting point for the development of novel antiviral drugs that target the interface of HIV-1 viral proteins with their host partners.
authors: Center for Sickle Cell Disease, Howard University, Washington, DC, United States of America.
authors: Tatiana
authors: T
authors: Ammosova
authors: Maxim
authors: M
authors: Platonov
authors: Venkat R K
authors: VR
authors: Yedavalli
authors: Yuri
authors: Y
authors: Obukhov
authors: Victor R
authors: VR
authors: Gordeuk
authors: Kuan-Teh
authors: KT
authors: Jeang
authors: Dmytro
authors: D
authors: Kovalskyy
authors: Sergei
authors: S
authors: Nekhai
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D019380:Anti-HIV Agents / Q000737:chemistry / Q000494:pharmacology*; D001665:Binding Sites; D055162:Biocatalysis / Q000187:drug effects*; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000378:metabolism; D015497:HIV-1 / Q000187:drug effects* / Q000235:genetics / Q000502:physiology; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions / Q000187:drug effects; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism; D010455:Peptides / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D054645:Protein Phosphatase 1 / Q000037:antagonists & inhibitors* / Q000737:chemistry* / Q000378:metabolism; D021381:Protein Transport / Q000187:drug effects; D016601:RNA-Binding Proteins / Q000378:metabolism; D054852:Small Molecule Libraries / Q000737:chemistry / Q000494:pharmacology*; D014158:Transcription, Genetic / Q000187:drug effects; D014779:Virus Replication / Q000187:drug effects; D054322:tat Gene Products, Human Immunodeficiency Virus / Q000378:metabolism
chemical_list: D019380:Anti-HIV Agents; D004268:DNA-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; D009687:Nuclear Proteins; C110225:PPP1R10 protein, human; D010455:Peptides; D016601:RNA-Binding Proteins; D054852:Small Molecule Libraries; C021042:protein phosphatase inhibitor-1; D054322:tat Gene Products, Human Immunodeficiency Virus; D054645:Protein Phosphatase 1