Plays an important role in mitochondrial mRNA editing by promoting the assembly of the mRNA editosome (PubMed:26769962, PubMed:31034523). Facilitates the recruitment of mRNA to the REH2C complex and promotes the interaction between various editing complexes including REH2C, GRBC, REMC and RECC complexes (PubMed:26769962, PubMed:31034523). Component of the REH2-associated complex (REH2C) composed of helicase REH2, associated factors H2F1 and H2F2, and mRNAs at various editing stages; the formation of the complex is RNA-independent (PubMed:26769962, PubMed:31034523). Within the complex, interacts with REH2; the interaction is direct (PubMed:26769962). Interacts with various editing complexes including the RNA editing core (RECC) complex, the gRNA-binding (GRBC) complex (also known as the MRB1 complex) and the RNA editing mediator (REMC) complex (PubMed:26769962, PubMed:31034523). Expressed at the procyclic stage (at protein level). RNAi-mediated knockdown at the procyclic stage causes a reduction in mitochondrial mRNA editing (PubMed:26769962). Formation of the REH2C complex is not affected but REH2C complex association with the GRBC, REMC, RECC complexes and with and pre-mRNA is impaired (PubMed:26769962). Integrity of the GRBC complex is not affected but GRBC complex association with the RECC complex and pre-mRNA is reduced (PubMed:26769962). Causes a slight decrease in REH2 protein levels (PubMed:26769962, PubMed:31034523). Does not affect the RNA unwinding activity of the REH2C complex (PubMed:26769962). Extended N-terminus. Extended N-terminus.