Human Cells Require Non-stop Ribosome Rescue Activity in Mitochondria

Bacteria use trans-translation and the alternative rescue factors ArfA (P36675) and ArfB (Q9A8Y3) to hydrolyze peptidyl-tRNA on ribosomes that stall near the 3' end of an mRNA during protein synthesis. The eukaryotic protein ICT1 (Q14197) is homologous to ArfB. In vitro ribosome rescue assays o...

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Main Authors:	Feaga, Heather A., Quickel, Michael D., Hankey-Giblin, Pamela A., Keiler, Kenneth C.
Format:	Online
Language:	English
Published:	Public Library of Science 2016
Online Access:	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4814080/

id	pubmed-4814080
recordtype	oai_dc
spelling	pubmed-48140802016-04-05 Human Cells Require Non-stop Ribosome Rescue Activity in Mitochondria Feaga, Heather A. Quickel, Michael D. Hankey-Giblin, Pamela A. Keiler, Kenneth C. Research Article Bacteria use trans-translation and the alternative rescue factors ArfA (P36675) and ArfB (Q9A8Y3) to hydrolyze peptidyl-tRNA on ribosomes that stall near the 3' end of an mRNA during protein synthesis. The eukaryotic protein ICT1 (Q14197) is homologous to ArfB. In vitro ribosome rescue assays of human ICT1 and Caulobacter crescentus ArfB showed that these proteins have the same activity and substrate specificity. Both ArfB and ICT1 hydrolyze peptidyl-tRNA on nonstop ribosomes or ribosomes stalled with ≤6 nucleotides extending past the A site, but are unable to hydrolyze peptidyl-tRNA when the mRNA extends ≥14 nucleotides past the A site. ICT1 provided sufficient ribosome rescue activity to support viability in C. crescentus cells that lacked both trans-translation and ArfB. Likewise, expression of ArfB protected human cells from death when ICT1 was silenced with siRNA. These data indicate that ArfB and ICT1 are functionally interchangeable, and demonstrate that ICT1 is a ribosome rescue factor. Because ICT1 is essential in human cells, these results suggest that ribosome rescue activity in mitochondria is required in humans. Public Library of Science 2016-03-30 /pmc/articles/PMC4814080/ /pubmed/27029019 http://dx.doi.org/10.1371/journal.pgen.1005964 Text en © 2016 Feaga et al http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
repository_type	Open Access Journal
institution_category	Foreign Institution
institution	US National Center for Biotechnology Information
building	NCBI PubMed
collection	Online Access
language	English
format	Online
author	Feaga, Heather A. Quickel, Michael D. Hankey-Giblin, Pamela A. Keiler, Kenneth C.
spellingShingle	Feaga, Heather A. Quickel, Michael D. Hankey-Giblin, Pamela A. Keiler, Kenneth C. Human Cells Require Non-stop Ribosome Rescue Activity in Mitochondria
author_facet	Feaga, Heather A. Quickel, Michael D. Hankey-Giblin, Pamela A. Keiler, Kenneth C.
author_sort	Feaga, Heather A.
title	Human Cells Require Non-stop Ribosome Rescue Activity in Mitochondria
title_short	Human Cells Require Non-stop Ribosome Rescue Activity in Mitochondria
title_full	Human Cells Require Non-stop Ribosome Rescue Activity in Mitochondria
title_fullStr	Human Cells Require Non-stop Ribosome Rescue Activity in Mitochondria
title_full_unstemmed	Human Cells Require Non-stop Ribosome Rescue Activity in Mitochondria
title_sort	human cells require non-stop ribosome rescue activity in mitochondria
description	Bacteria use trans-translation and the alternative rescue factors ArfA (P36675) and ArfB (Q9A8Y3) to hydrolyze peptidyl-tRNA on ribosomes that stall near the 3' end of an mRNA during protein synthesis. The eukaryotic protein ICT1 (Q14197) is homologous to ArfB. In vitro ribosome rescue assays of human ICT1 and Caulobacter crescentus ArfB showed that these proteins have the same activity and substrate specificity. Both ArfB and ICT1 hydrolyze peptidyl-tRNA on nonstop ribosomes or ribosomes stalled with ≤6 nucleotides extending past the A site, but are unable to hydrolyze peptidyl-tRNA when the mRNA extends ≥14 nucleotides past the A site. ICT1 provided sufficient ribosome rescue activity to support viability in C. crescentus cells that lacked both trans-translation and ArfB. Likewise, expression of ArfB protected human cells from death when ICT1 was silenced with siRNA. These data indicate that ArfB and ICT1 are functionally interchangeable, and demonstrate that ICT1 is a ribosome rescue factor. Because ICT1 is essential in human cells, these results suggest that ribosome rescue activity in mitochondria is required in humans.
publisher	Public Library of Science
publishDate	2016
url	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4814080/
_version_	1613559868086550528

Human Cells Require Non-stop Ribosome Rescue Activity in Mitochondria

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