Characterization of a small tRNA ‐binding protein that interacts with the archaeal proteasome complex

Gaëlle Hogrel (1) , Laura Marino-Puertas (1) , Sébastien Laurent , Ziad Ibrahim (1) , Jacques Covès (1) , Eric Girard (1) , Frank Gabel (1) , Daphna Fenel (1) , Marie‐claire Daugeron (2) , Béatrice Clouet-d'Orval (3) , Tamara Basta (1) , Didier Flament (4) , Bruno Franzetti (1)

1 IBS - UMR 5075 - Institut de biologie structurale
2 I2BC - Institut de Biologie Intégrative de la Cellule
3 LMGM - Laboratoire de microbiologie et génétique moléculaires - UMR5100
4 LM2E - Laboratoire de Microbiologie des Environnements Extrêmophiles

The proteasome system allows the elimination of functional or structurally impaired proteins. This includes the degradation of nascent peptides. In Archaea, how the proteasome complex interacts with the translational machinery remains to be described. Here, we characterized a small orphan protein, Q9UZY3 (UniProt ID), conserved in Thermococcales. The protein was identified in native pull-down experiments using the proteasome regulatory complex (proteasome-activating nucleotidase [PAN]) as bait. X-ray crystallography and small-angle X-ray scattering experiments revealed that the protein is monomeric and adopts a β-barrel core structure with an oligonucleotide/oligosaccharide-binding (OB)-fold, typically found in translation elongation factors. Mobility shift experiment showed that Q9UZY3 displays transfer ribonucleic acid (tRNA)-binding properties. Pull-downs, co-immunoprecipitation and isothermal titration calorimetry (ITC) studies revealed that Q9UZY3 interacts in vitro with PAN. Native pull-downs and proteomic analysis using different versions of Q9UZY3 showed that the protein interacts with the assembled PAN-20S proteasome machinery in Pyrococcus abyssi (Pa) cellular extracts. The protein was therefore named Pbp11, for Proteasome-Binding Protein of 11 kDa. Interestingly, the interaction network of Pbp11 also includes ribosomal proteins, tRNA-processing enzymes and exosome subunits dependent on Pbp11's N-terminal domain that was found to be essential for tRNA binding. Together these data suggest that Pbp11 participates in an interface between the proteasome and the translational machinery.

Keywords: Archaea; OB-fold; proteasome; protein-protein interaction; ribosome-associated quality control; tRNA binding

Domains: Structural Biology [q-bio.BM]

Gaëlle Hogrel, Laura Marino-Puertas, Sébastien Laurent, Ziad Ibrahim, Jacques Covès, et al.. Characterization of a small tRNA ‐binding protein that interacts with the archaeal proteasome complex. Molecular Microbiology, 2022, Bacterial macromolecular machineries, 118 (1-2), pp.16-29. ⟨10.1111/mmi.14948⟩. ⟨hal-03701716⟩