Required for proper chloroplast development, most likely through regulating plastid-encoded polymerase (PEP) dependent chloroplast transcription. Acts as a component of the transcriptionally active plastid chromosome that is required for plastid gene expression. Interacts with CITRX/TRXz (PubMed:20511297). Interacts with PTAC7 (PubMed:23082802). Self-interacts. Binds to FLN2. Associates with the plastid-encoded RNA polymerase (PEP) complex (PubMed:24019900). Albino seedlings leading to lethality. RNAi plants display abnormal plastids lacking internal membrane structures. Belongs to the carbohydrate kinase PfkB family.