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Crystal structure of Cex1p reveals the mechanism of tRNA trafficking between nucleus and cytoplasm.

Crystal structure of Cex1p reveals the mechanism of tRNA trafficking between nucleus and cytoplasm.

Authors :
Nozawa K
Ishitani R
Yoshihisa T
Sato M
Arisaka F
Kanamaru S
Dohmae N
Mangroo D
Senger B
Becker HD
Nureki O
Source :
Nucleic acids research [Nucleic Acids Res] 2013 Apr 01; Vol. 41 (6), pp. 3901-14. Date of Electronic Publication: 2013 Feb 08.
Publication Year :
2013

Abstract

In all eukaryotes, transcribed precursor tRNAs are maturated by processing and modification processes in nucleus and are transported to the cytoplasm. The cytoplasmic export protein (Cex1p) captures mature tRNAs from the nuclear export receptor (Los1p) on the cytoplasmic side of the nuclear pore complex, and it delivers them to eukaryotic elongation factor 1α. This conserved Cex1p function is essential for the quality control of mature tRNAs to ensure accurate translation. However, the structural basis of how Cex1p recognizes tRNAs and shuttles them to the translational apparatus remains unclear. Here, we solved the 2.2 Å resolution crystal structure of Saccharomyces cerevisiae Cex1p with C-terminal 197 disordered residues truncated. Cex1p adopts an elongated architecture, consisting of N-terminal kinase-like and a C-terminal α-helical HEAT repeat domains. Structure-based biochemical analyses suggested that Cex1p binds tRNAs on its inner side, using the positively charged HEAT repeat surface and the C-terminal disordered region. The N-terminal kinase-like domain acts as a scaffold to interact with the Ran-exportin (Los1p·Gsp1p) machinery. These results provide the structural basis of Los1p·Gsp1p·Cex1p·tRNA complex formation, thus clarifying the dynamic mechanism of tRNA shuttling from exportin to the translational apparatus.

Details

Language :
English
ISSN :
1362-4962
Volume :
41
Issue :
6
Database :
MEDLINE
Journal :
Nucleic acids research
Publication Type :
Academic Journal
Accession number :
23396276
Full Text :
https://doi.org/10.1093/nar/gkt010