Maf1-mediated repression of RNA polymerase III transcription inhibits tRNA degradation via RTD pathway

Model for eEF1A-mediated protection of tRNA^Val(AAC) from RTD degradation. Mature, hypomodified tRNA^Val(AAC) pool is aminoacylated by valyl-tRNA synthetase, bound by eEF1A, and delivered to ribosomes. A shift to restrictive conditions results in degradation of hypomodified tRNA^Val(AAC) by RTD pathway. It is unknown whether hypomodified tRNA can be efficiently charged and if it could be degraded prior to aminoacylation. Nevertheless, elevated population of eEF1A molecules favors their binding to tRNA^Val(AAC) and prevents tRNA^Val(AAC) interacting with nucleases. Increased availability of tRNA-free eEF1A molecules may be achieved by increased expression of TEF1 gene or decreased global tRNA synthesis by Pol III inhibition.