Mitochondrial RNA-binding protein involved in mitochondrial transcription regulation. Functions as a protective factor to maintain proper mitochondrial RNA level during stress. Acts at the transcription level and its protective function depends on its RNA binding ability (PubMed:31226201). Part of a mitoribosome-associated quality control pathway that prevents aberrant translation by responding to interruptions during elongation (PubMed:33243891, PubMed:31396629). As heterodimer with MTRF, ejects the unfinished nascent chain and peptidyl transfer RNA (tRNA), respectively, from stalled ribosomes. Recruitment of mitoribosome biogenesis factors to these quality control intermediates suggests additional roles for MTRES1 and MTRF during mitoribosome rescue (PubMed:33243891). Monomer (PubMed:31226201). Interacts with POLRMT (PubMed:31226201). Interacts (via S4 domain) with MTRFR (via C-terminus) (PubMed:33243891, PubMed:31396629). Associates with mitoribosomal S39 large subunit, peptidyl tRNA and nascent chain (PubMed:33243891, PubMed:31396629). Up-regulated upon depletion of mitochondrial nucleic acids.