Required for both formation and activity of the chloroplast NAD(P)H dehydrogenase (NDH) complex of the photosynthetic electron transport chain. May function in assembly or stabilization of the NDH complex (PubMed:16648216, PubMed:20444231). Required for the accumulation of NDH subcomplex A, which is a core part of NDH. May be involved in post-translational steps during the biogenesis of subcomplex A (PubMed:20444231). Previously localized in chloroplast thylakoid membrane fraction. A number of isoforms are produced. According to EST sequences. Impaired chloroplastic NAD(P)H dehydrogenase (NDH) activity, probably due to a reduced stability of the NDH complex.