Probable component of some protein complex required for chloroplast and palisade cell development (PubMed:15340011). Involved in C-to-U editing of chloroplastic RNA. Controls a large number of chloroplastic editing sites. Binds the editing recognition trans-factors PCMP-H51/CRR28 and PCMP-H12/OTP82 (PubMed:25768119). Interacts in vitro with the chloroplast-located protein CCD4/NCED4 (PubMed:15340011). Homodimer. Interacts with ORRM1. Interacts with PCMP-H51/CRR28 and PCMP-H12/OTP82 (PubMed:25768119). Interacts with ORRM6 (PubMed:28213559). Localizes at punctuate loci in chloroplasts. Weakly expressed in leaves and roots. Defects result in variegated plants that have leaves consisting of normal green and also white or yellow sectors in which chloroplast development is retarded or disrupted (PubMed:15340011, PubMed:25768119). Mutant plants exhibit severe editing defects in chloroplastic transcripts (PubMed:25768119).