Abstract
A typical feature of eukaryotic aminoacyl-tRNA synthetases (aaRSs) is the evolutionary gain of domains at either the N- or C-terminus, which frequently mediating protein–protein interaction. TARSL2 (mouse Tarsl2), encoding a threonyl-tRNA synthetase-like protein (ThrRS-L), is a recently identified aaRS-duplicated gene in higher eukaryotes, with canonical functions in vitro, which exhibits a different N-terminal extension (N-extension) from TARS (encoding ThrRS). We found the first half of the N-extension of human ThrRS-L (hThrRS-L) is homologous to that of human arginyl-tRNA synthetase. Using the N-extension as a probe in a yeast two-hybrid screening, AIMP1/p43 was identified as an interactor with hThrRS-L. We showed that ThrRS-L is a novel component of the mammalian multiple tRNA synthetase complex (MSC), and is reliant on two leucine zippers in the N-extension for MSC-incorporation in humans, and mouse cell lines and muscle tissue. The N-extension was sufficient to target a foreign protein into the MSC. The results from a Tarsl2-deleted cell line showed that it does not mediate MSC integrity. The effect of phosphorylation at various sites of hThrRS-L on its MSC-targeting is also explored. In summary, we revealed that ThrRS-L is a bona fide component of the MSC, which is mediated by a newly evolved N-extension domain.
Highlights
The genetic code is a universal algorithm for linking nucleotide triplets in mRNAs to the amino acids in proteins via mRNA translation
We identified p43 is one of the proteins that interact with human ThrRS (hThrRS)-L, and further provided extensive data showing that ThrRS-L is a bona fide member of the multiple transfer RNAs (tRNAs) synthetase complex (MSC) in humans and mice
Sequence analysis among bacterial ThrRSs, canonical eukaryotic cytoplasmic ThrRSs and mammalian ThrRS-Ls showed that both eukaryotic cytoplasmic ThrRSs and ThrRS-Ls have acquired newly evolved N-terminal extensions (N-extensions) when compared with bacterial ThrRSs [33,34] (Figure 1A)
Summary
The genetic code is a universal algorithm for linking nucleotide triplets in mRNAs to the amino acids in proteins via mRNA translation (protein synthesis). AminoacyltRNA synthetases (aaRSs) comprise a ubiquitously expressed family of enzymes that catalyze the esterification reaction to ligate transfer RNAs (tRNAs) with their cognate amino acids to generate aminoacyl-tRNAs for protein biosynthesis at the ribosome [1,2]. TRNA charging (aminoacylation) occurs in two-step reactions involving amino acid activation, with the generation of intermediate aminoacyl-AMP, and transfer of the aminoacyl moiety of the intermediate to A76 of tRNA [1,3]. The activities of aminoacylation and editing are canonical functions of aaRSs that maintain the speed and fidelity of genetic code transduction. All present-day aaRSs contain catalytic and anticodon binding domains to perform aminoacylation, together with editing domains in some aaRSs to carry out the editing activity. During evolution of aaRSs from prokaryotes to archaea and eukaryotes, certain aaRSs obtain new appended domains, usually at the N- or C-terminus [8], with unique structural characteristics that are not a part of the catalytic core, but frequently mediate
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
