title: TRIM5α is a SUMO substrate.
abstract: BACKGROUND
  The TRIM5α restriction factor interferes with retroviral infections by inhibiting an early step of viral replication. TRIM5α activity was recently proposed to be regulated by the SUMO machinery and one SUMO consensus conjugation site as well as three putative SUMO interacting motifs (SIMs) were identified within TRIM5α sequence. Whereas mutation of the SIM sequences was found to abolish TRIM5α antiviral activity, mutation of the consensus SUMO conjugation site did not affect its restriction capacity, although this putative site has never been shown to be actually a SUMO substrate.
  
  
  RESULTS
  Here we further demonstrate that TRIM5α relies on the SUMO machinery to promote restriction, since SUMO1 overexpression enhances TRIM5α-mediated retroviral inhibition whereas knockdown of SUMO1 or E2 SUMO conjugating enzyme Ubc9 prevents restriction. Furthermore, we show for the first time that TRIM5α is SUMOylated both in vitro and in cellulo and that Lysine 10 is the main SUMOylation site. Mutation of the consensus SUMO conjugation motif in position 10 abrogated SUMOylation at this position, but did not disrupt TRIM5α antiviral activity.
  
  
  CONCLUSIONS
  Altogether, our results confirm that the SUMO machinery is involved in TRIM5α-mediated retroviral restriction, and demonstrate that TRIM5α is a SUMO 1 and SUMO 2 substrate. The inability to abrogate TRIM5α antiviral activity by mutating its main SUMO conjugation motif supports the notion that non-covalent interaction with SUMO or SUMOylated proteins rather than TRIM5α direct SUMOylation is required.
authors.affiliation: INSERM UMR-S 1124, Université Paris Descartes, 45 rue des Saints-Pères, 75006, Paris, France. jacques.dutrieux@inserm.fr.
authors.forename: Jacques
authors.initials: J
authors.lastname: Dutrieux
authors.affiliation: INSERM U941, University Institute of Hematology, Saint-Louis Hospital, 75010, Paris, France. debora.portilho@inserm.fr.
authors.forename: Débora M
authors.initials: DM
authors.lastname: Portilho
authors.affiliation: INSERM U941, University Institute of Hematology, Saint-Louis Hospital, 75010, Paris, France. nathalie.arhel@inserm.fr.
authors.forename: Nathalie J
authors.initials: NJ
authors.lastname: Arhel
authors.affiliation: LBPA, CNRS UMR 8113, Ecole Normale Supérieure de Cachan, 94235, Cachan, France. uriel.hazan@ens-cachan.fr.
authors.forename: Uriel
authors.initials: U
authors.lastname: Hazan
authors.affiliation: INSERM UMR-S 1124, Université Paris Descartes, 45 rue des Saints-Pères, 75006, Paris, France. sebastien.nisole@inserm.fr.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Nisole
mesh_terms: D000818:Animals; D002460:Cell Line; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D008253:Macaca mulatta; D011506:Proteins / Q000378:metabolism*; D059748:Proteolysis; D025842:SUMO-1 Protein / Q000378:metabolism*; D025841:Small Ubiquitin-Related Modifier Proteins / Q000378:metabolism*; D058207:Sumoylation; D044767:Ubiquitin-Protein Ligases
chemical_list: D011506:Proteins; D025842:SUMO-1 Protein; C495501:SUMO1 protein, human; C117909:SUMO2 protein, human; D025841:Small Ubiquitin-Related Modifier Proteins; C482587:TRIM5(alpha) protein, rhesus monkey; D044767:Ubiquitin-Protein Ligases