title: RNA binding targets aminoacyl-tRNA synthetases to translating ribosomes.
abstract: Here, we examine tRNA-aminoacyl synthetase (ARS) localization in protein synthesis. Proteomics reveals that ten of the twenty cytosolic ARSs associate with ribosomes in sucrose gradients: phenylalanyl-RS (FRS), and the 9 ARSs that form the multi-ARS complex (MSC). Using the ribopuromycylation method (RPM) for localizing intracellular translation, we show that FRS and the MSC, and to a lesser extent other ARSs, localize to translating ribosomes, most strikingly when translation is restricted to poxvirus or alphavirus factories in infected cells. Immunoproximity fluorescence indicates close proximity between MSC and the ribosome. Stress induced-translational shutdown recruits the MSC to stress-granules, a depot for mRNA and translation components. MSC binding to mRNA provides a facile explanation for its delivery to translating ribosomes and stress granules. These findings, along with the abundance of the MSC (9 × 10(6) copies per cell, roughly equimolar with ribosomes), is consistent with the idea that MSC specificity, recently reported to vary with cellular stress (Netzer, N., Goodenbour, J. M., David, A., Dittmar, K. A., Jones, R. B., Schneider, J. R., Boone, D., Eves, E. M., Rosner, M. R., Gibbs, J. S., Embry, A., Dolan, B., Das, S., Hickman, H. D., Berglund, P., Bennink, J. R., Yewdell, J. W., and Pan, T. (2009) Nature 462, 522-526) can be modulated at the level of individual mRNAs to modify decoding of specific gene products.
authors: Laboratory of Viral Diseases, NIAID, National Institutes of Health, Bethesda, Maryland 20892, USA.
authors: Alexandre
authors: A
authors: David
authors: Nir
authors: N
authors: Netzer
authors: Michael Brad
authors: MB
authors: Strader
authors: Suman R
authors: SR
authors: Das
authors: Cai Yun
authors: CY
authors: Chen
authors: James
authors: J
authors: Gibbs
authors: Philippe
authors: P
authors: Pierre
authors: Jack R
authors: JR
authors: Bennink
authors: Jonathan W
authors: JW
authors: Yewdell
mesh_terms: D000524:Alphavirus / Q000378:metabolism; D018354:Alphavirus Infections / Q000378:metabolism; D000604:Amino Acyl-tRNA Synthetases / Q000378:metabolism*; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D011212:Poxviridae / Q000378:metabolism; D011213:Poxviridae Infections / Q000378:metabolism; D014176:Protein Biosynthesis / Q000502:physiology*; D012333:RNA, Messenger / Q000378:metabolism*; D012270:Ribosomes / Q000378:metabolism*
chemical_list: D012333:RNA, Messenger; D000604:Amino Acyl-tRNA Synthetases