Involved in the initial differentiation of the proplastid during the embryo development. Also required for correct cotyledon, true leaf and cauline leaf margin development. Interacts with AKR. No homodimerization observed. Expressed in roots, inflorescence stems, flowers, siliques, dry seeds and mature cauline leaves. Expressed during embryo development and after the bolting stage, in mature culine leaves and in flowers. Not detected at the protein level at the rosette stage of development.