Transfer RNA travels from the cytoplasm to organelles

• Published in: Wiley interdisciplinary reviews. RNA 2011-11, Vol.2 (6), p.802-817
• Main Authors: Rubio, Mary Anne T., Hopper, Anita K.
• Format: Article
• Language: English
• Subjects: Active Transport, Cell Nucleus; Animals; Biological Transport, Active; Cytoplasm; Cytoplasm - metabolism; Genomes; Humans; Localization; Mitochondria; Mitochondria - metabolism; Models, Biological; Models, Molecular; Nuclear transport; Nucleic Acid Conformation; Organelles; Organelles - metabolism; Plants - metabolism; Protein biosynthesis; Protein synthesis; Protein transport; Proteins; Ribosomes; RNA processing; RNA transport; RNA, Fungal - metabolism; RNA, Plant - metabolism; RNA, Protozoan - metabolism; RNA, Transfer - chemistry; RNA, Transfer - metabolism; Saccharomyces cerevisiae - metabolism; Transfer RNA; tRNA; Trypanosomatina - metabolism
• ISSN: 1757-7004; 1757-7012
• DOI: 10.1002/wrna.93

Transfer RNAs (tRNAs) encoded by the nuclear genome are surprisingly dynamic. Although tRNAs function in protein synthesis occurring on cytoplasmic ribosomes, tRNAs can transit from the cytoplasm to the nucleus and then again return to the cytoplasm by a process known as the tRNA retrograde process. Subsets of the cytoplasmic tRNAs are also imported into mitochondria and function in mitochondrial protein synthesis. The numbers of tRNA species that are imported into mitochondria differ among organisms, ranging from just a few to the entire set needed to decode mitochondrially encoded mRNAs. For some tRNAs, import is dependent on the mitochondrial protein import machinery, whereas the majority of tRNA mitochondrial import is independent of this machinery. Although cytoplasmic proteins and proteins located on the mitochondrial surface participating in the tRNA import process have been described for several organisms, the identity of these proteins differ among organisms. Likewise, the tRNA determinants required for mitochondrial import differ among tRNA species and organisms. Here, we present an overview and discuss the current state of knowledge regarding the mechanisms involved in the tRNA retrograde process and continue with an overview of tRNA import into mitochondria. Finally, we highlight areas of future research to understand the function and regulation of movement of tRNAs between the cytoplasm and organelles. WIREs RNA 2011 2 802–817 DOI: 10.1002/wrna.93 This article is categorized under: RNA Processing > tRNA Processing RNA Export and Localization > Nuclear Export/Import RNA Export and Localization > RNA Localization