Alanine tails signal proteolysis in bacterial ribosome-associated quality control

• Verfasst von: Lytvynenko, Iryna [VerfasserIn]
• Verfasst von: Paternoga, Helge [VerfasserIn]
• Verfasst von: Thrun, Anna [VerfasserIn]
• Verfasst von: Nagler, Katja [VerfasserIn]
• Verfasst von: Anders, Simon [VerfasserIn]
• Verfasst von: Bischofs-Pfeifer, Ilka [VerfasserIn]
• Verfasst von: Joazeiro, Claudio A. P. [VerfasserIn]
• Titel: Alanine tails signal proteolysis in bacterial ribosome-associated quality control
• Verf.angabe: Iryna Lytvynenko, Helge Paternoga, Anna Thrun, Annika Balke, Tina A. Müller, Christina H. Chiang, Katja Nagler, George Tsaprailis, Simon Anders, Ilka Bischofs, Julie A. Maupin-Furlow, Christian M.T. Spahn, Claudio A.P. Joazeiro
• E-Jahr: 2019
• Jahr: May 30, 2019
• Umfang: 38 S.
• Fussnoten: Gesehen am 02.08.2019
• Titel Quelle: Enthalten in: Cell
• Ort Quelle: [Cambridge, Mass.] : Cell Press, 1974
• Jahr Quelle: 2019
• Band/Heft Quelle: 178(2019,1) Seite 76-90e22
• ISSN Quelle: 1097-4172
• DOI: doi:10.1016/j.cell.2019.05.002
• Datenträger: Online-Ressource
• Sprache: eng
• Sach-SW: Ala tails
• Sach-SW: bacterial proteolysis
• Sach-SW: CAT tails
• Sach-SW: Ltn1
• Sach-SW: protein quality control
• Sach-SW: ribosome stalling
• Sach-SW: RQC
• Sach-SW: Rqc2
• Sach-SW: RqcH
• Sach-SW: ssrA
• K10plus-PPN: 1670490106

Abstract

In ribosome-associated quality control (RQC), Rqc2/NEMF closely supports the E3 ligase Ltn1/listerin in promoting ubiquitylation and degradation of aberrant nascent-chains obstructing large (60S) ribosomal subunits-products of ribosome stalling during translation. However, while Ltn1 is eukaryote-specific, Rqc2 homologs are also found in bacteria and archaea; whether prokaryotic Rqc2 has an RQC-related function has remained unknown. Here, we show that, as in eukaryotes, a bacterial Rqc2 homolog (RqcH) recognizes obstructed 50S subunits and promotes nascent-chain proteolysis. Unexpectedly, RqcH marks nascent-chains for degradation in a direct manner, by appending C-terminal poly-alanine tails that act as degrons recognized by the ClpXP protease. Furthermore, RqcH acts redundantly with tmRNA/ssrA and protects cells against translational and environmental stresses. Our results uncover a proteolytic-tagging mechanism with implications toward the function of related modifications in eukaryotes and suggest that RQC was already active in the last universal common ancestor (LUCA) to help cope with incomplete translation.