Possibly has a role in RNA transcription or processing during stress (By similarity). Involved in C-to-U editing of mitochondrial RNA. Functions as minor mitochondrial editing factor. Controls 6 percent of the mitochondrial editing sites (PubMed:25800738). Homodimer (PubMed:25800738). Interacts with ORRM2 and MORF8/RIP1 (PubMed:25800738). Interacts with RBG5/ORRM4 (PubMed:26578708). Binds to RBG2/ORRM5 (PubMed:28549172). Up-regulated by cold stress. No visible phenotype under normal growth conditions, but mutant plants exhibit severe editing defects in mitochondrial transcripts. Belongs to the GR-RBP family.