title: SAMHD1 is active in cycling cells permissive to HIV-1 infection.
abstract: SAMHD1 is a triphosphohydrolase that restricts HIV-1 by limiting the intracellular dNTP pool required for reverse transcription. Although SAMHD1 is expressed and active/unphosphorylated in most cell lines, its restriction activity is thought to be relevant only in non-cycling cells. However, an in depth evaluation of SAMHD1 function and relevance in cycling cells is required. Here, we show that SAMHD1-induced degradation by HIV-2 Vpx affects the dNTP pool and HIV-1 replication capacity in the presence of the 3'-azido-3'-deoxythymidine (AZT) in cycling cells. Similarly, in SAMHD1 knockout cells, HIV-1 showed increased replicative capacity in the presence of nucleoside inhibitors, especially AZT, that was reverted by re-expression of wild type SAMHD1. Sensitivity to non-nucleoside inhibitors (nevirapine and efavirenz) or the integrase inhibitor raltegravir was not affected by SAMHD1. Combination of three mutations (S18A, T21A, T25A) significantly prevented SAMHD1 phosphorylation but did not significantly affect HIV-1 replication in the presence of AZT. Our results demonstrate that SAMHD1 is active in HIV-1 permissive cells, does not modify susceptibility to HIV-1 infection but strongly affects sensitivity to nucleoside inhibitors.
authors.affiliation: AIDS Research Institute - IrsiCaixa and Health Research, Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain.
authors.forename: Roger
authors.initials: R
authors.lastname: Badia
authors.affiliation: AIDS Research Institute - IrsiCaixa and Health Research, Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain.
authors.forename: Maria
authors.initials: M
authors.lastname: Pujantell
authors.affiliation: Research Group on Neuromuscular and Mitochondrial Disorders, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Torres-Torronteras
authors.affiliation: Centro de Biología Molecular "Severo Ochoa", Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Madrid, Spain.
authors.forename: Luis
authors.initials: L
authors.lastname: Menéndez-Arias
authors.affiliation: Research Group on Neuromuscular and Mitochondrial Disorders, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Spain.
authors.forename: Ramón
authors.initials: R
authors.lastname: Martí
authors.affiliation: Laboratory of Molecular Embryology, The Rockefeller University, New York, NY, USA.
authors.forename: Albert
authors.initials: A
authors.lastname: Ruzo
authors.affiliation: AIDS Research Institute - IrsiCaixa and Health Research, Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain; Joint IRB-BSC-CRG Program in Computational Biology, Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology, Barcelona, Catalonia, Spain.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Pauls
authors.affiliation: AIDS Research Institute - IrsiCaixa and Health Research, Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain.
authors.forename: Bonaventura
authors.initials: B
authors.lastname: Clotet
authors.affiliation: AIDS Research Institute - IrsiCaixa and Health Research, Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain.
authors.forename: Ester
authors.initials: E
authors.lastname: Ballana
authors.affiliation: AIDS Research Institute - IrsiCaixa and Health Research, Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain. Electronic address: jaeste@irsicaixa.es.
authors.forename: José A
authors.initials: JA
authors.lastname: Esté
authors.affiliation: AIDS Research Institute - IrsiCaixa and Health Research, Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain. Electronic address: eriveira@irsicaixa.es.
authors.forename: Eva
authors.initials: E
authors.lastname: Riveira-Muñoz
mesh_terms: D002460:Cell Line; D064112:Clustered Regularly Interspaced Short Palindromic Repeats; D004261:DNA Replication / Q000187:drug effects; D000072669:Gene Editing; D015870:Gene Expression; D055785:Gene Knockdown Techniques; D057809:HEK293 Cells; D015658:HIV Infections / Q000378:metabolism; D015497:HIV-1 / Q000187:drug effects* / Q000472:pathogenicity; D015498:HIV-2 / Q000187:drug effects; D054884:Host-Pathogen Interactions; D006801:Humans; D010766:Phosphorylation; D048348:Reverse Transcription / Q000187:drug effects; D000076106:SAM Domain and HD Domain-Containing Protein 1 / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D054334:Viral Regulatory and Accessory Proteins / Q000187:drug effects; D014779:Virus Replication / Q000187:drug effects*; D015215:Zidovudine / Q000494:pharmacology
chemical_list: C074286:VPX protein, Human immunodeficiency virus 2; D054334:Viral Regulatory and Accessory Proteins; D015215:Zidovudine; D000076106:SAM Domain and HD Domain-Containing Protein 1; C484280:SAMHD1 protein, human
keywords: CRISPR; Genome editing; SAMHD1; dNTPase activity