May be involved in neural development. Involved in regulation of osteoblast function and bone formation. Involved in matrix vesicle release by osteoblasts; this function seems to involve maintenance of the actin cytoskeleton. May be involved in cellular trafficking of SERT and thereby in regulation of serotonin uptake (By similarity). Interacts with SERT. Colocalizes with SERT at the plasma membrane. Belongs to the myelin proteolipid protein family.