Component of the plastid division machinery consisting in a binary fission accomplished by the simultaneous constriction of the FtsZ ring on the stromal side of the inner envelope membrane, and the ARC5/DRP5B ring on the cytosolic side of the outer envelope membrane (PubMed:28248291). Positive factor of chloroplast division required, with a dosage effect, to mediate the recruitment and dimerization of ARC5/DRP5B at the midplastid constriction site in the cytoplasm at plastid outer envelope membranes (OEMs) (PubMed:28248291, PubMed:27988788, PubMed:32005784). Prevents ARC5/DRP5B GTPase acrivity (PubMed:27988788). Relays plastid division site position between stroma and outer surface via interactions with the cytoplasmic ARC5/DRP5B and the inner membrane ARC6 that recruits stromal FtsZ ring (PubMed:28248291). Binding to phosphatidylinositol 4-phosphate (PI4P) modulates negatively chloroplast division (PubMed:25736058). Interacts (via C-terminus) with ARC6 (via C-terminus) in the chloroplast intermembrane space; this interaction induces ARC6 homodimerization and leads to the formation of an heterotetramer containing two ARC6 and two PDV2 subunits (PubMed:18812496, PubMed:28248291). Interacts with ARC5/DRP5B (PubMed:32005784). Plastid equatorial positioning in a discontinuous ring mediated by ARC6 (PubMed:18812496). Colocalizes with ARC5/DRP5B at the chloroplast division site (PubMed:32005784). Mostly expressed in young leaves. Highest levels in young developing leaves with a sharp expression decrease in fast-growing and mature leaves (at protein level). Slightly induced by gibberellic acid (GA). Reduced number of constricted and large chloroplasts (PubMed:16998069, PubMed:18812496). Attenuated PDV2-induced ARC6 dimerization in the chloroplast intermembrane space leading to an abnormal morphology of ARC6 rings thus compromizing plastidial division (PubMed:28248291). Altered localization of ARC5/DRP5B in cytosol only rather than at the constriction sites of enlarged chloroplasts (PubMed:32005784). In pd116, reduced number of dumbbell-shaped and large chloroplasts in mesophyll cells, with sometimes unique giant chloroplasts (PubMed:27988788).