Voltage dependent anion channel required for acidification and functions of the Golgi apparatus that may function in counter-ion conductance (PubMed:18794847). Plays a role in lymphocyte development, probably by acting as a RABL3 effector in hematopoietic cells (By similarity). Homotrimer (By similarity). Interacts with RABL3; the interaction stabilizes GPR89 (By similarity). Delayed transport of newly synthesized protein from the Golgi to the plasma membrane, impaired glycosylation of proteins along the exocytic pathway, and structural disorganization of the Golgi apparatus. Defects are associated with decreased acidification of the cisternae of the Golgi and trans-Golgi network by 0.4-0.5 pH units with no effect on lysosomal pH and no effect on endocytosis or recycling. Experiments do not strictly demonstrate that altered chloride permeability of the Golgi or that the lack of acidification is due to absence of counterion conductance in the absence of GPR89/GPHR. It is therefore possible that GPR89/GPHR regulates Golgi pH by some other mechanism (PubMed:18794847). Belongs to the Golgi pH regulator (TC 1.A.38) family.