Major protein of the aragonitic otoconia. It is unlikely that this protein has phospholipase A2 activity. Monomer. Otoconial membrane in the maculae of the saccule and utricle. Otoconia are composites of proteins and inorganic crystals formed in the peripheral portion of the vestibular system of vertebrates. The otoconial membranes contain small crystals of calcium carbonate known as otoliths (ear stones) if there is a single deposit or as otoconia (ear dust) if there are many. Each mineral polymorph of otoconia has a protein unique to that polymorph. Belongs to the phospholipase A2 family.