Aminoacyl-tRNA synthetases cofactors play important roles in coordinating aminoacylation and translation. In this study, we described an additional function of the fission yeast aminoacyl-tRNA synthetases cofactor Asc1 in translation. We found that Asc1 directly bound and stabilized the interaction between small ribosomal protein Rps0A/uS2 and eukaryotic initiation factor eIF3a. In the absence of Asc1, the interaction between eIF3a and Rps0A/uS2 was compromised. The interaction between Rps0A/uS2 and eIF3a mediates the 40S ribosomal subunit binding of eIF3 in the 43S preinitiation complex formation to stimulate translation initiation. Keeping with this idea, in asc1 mutant, the association of mRNA with 40S ribosomal subunit was defective and protein synthesis was compromised. To show that Asc1 is directly involved in translation, we have demonstrated that addition of recombinant Asc1 was able to rescue the translation defect of asc1 mutant in a cell-free system. Furthermore, this function of Asc1 was likely to be evolutionarily conserved as similar interaction with eIF3a and Rps0A/uS2 could be identified in the budding yeast and human aminoacyl-tRNA synthetases cofactors. Together, these results identified a function of aminoacyl-tRNA synthetases cofactors in translation pre-initiation complex formation that added significantly to the expanded functions associated with aminoacyl-tRNA synthetases and their cofactors.
Date:
2019-10
Relation:
Molecular and Cellular Biology. 2019 Oct;39(19):Article number e00161-19.
