RsfA (YbeB) proteins are conserved ribosomal silencing factors.

Autor: Roman Häuser, Markus Pech, Jaroslaw Kijek, Hiroshi Yamamoto, Björn Titz, Florian Naeve, Andrey Tovchigrechko, Kaori Yamamoto, Witold Szaflarski, Nono Takeuchi, Thorsten Stellberger, Markus E Diefenbacher, Knud H Nierhaus, Peter Uetz
Jazyk: angličtina
Rok vydání: 2012
Předmět:
Zdroj: PLoS Genetics, Vol 8, Iss 7, p e1002815 (2012)
Druh dokumentu: article
ISSN: 1553-7390
1553-7404
DOI: 10.1371/journal.pgen.1002815
Popis: The YbeB (DUF143) family of uncharacterized proteins is encoded by almost all bacterial and eukaryotic genomes but not archaea. While they have been shown to be associated with ribosomes, their molecular function remains unclear. Here we show that YbeB is a ribosomal silencing factor (RsfA) in the stationary growth phase and during the transition from rich to poor media. A knock-out of the rsfA gene shows two strong phenotypes: (i) the viability of the mutant cells are sharply impaired during stationary phase (as shown by viability competition assays), and (ii) during transition from rich to poor media the mutant cells adapt slowly and show a growth block of more than 10 hours (as shown by growth competition assays). RsfA silences translation by binding to the L14 protein of the large ribosomal subunit and, as a consequence, impairs subunit joining (as shown by molecular modeling, reporter gene analysis, in vitro translation assays, and sucrose gradient analysis). This particular interaction is conserved in all species tested, including Escherichia coli, Treponema pallidum, Streptococcus pneumoniae, Synechocystis PCC 6803, as well as human mitochondria and maize chloroplasts (as demonstrated by yeast two-hybrid tests, pull-downs, and mutagenesis). RsfA is unrelated to the eukaryotic ribosomal anti-association/60S-assembly factor eIF6, which also binds to L14, and is the first such factor in bacteria and organelles. RsfA helps cells to adapt to slow-growth/stationary phase conditions by down-regulating protein synthesis, one of the most energy-consuming processes in both bacterial and eukaryotic cells.
Databáze: Directory of Open Access Journals
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