Collagen-like protein specifically expressed in the inner ear, which provides an organic scaffold for otoconia, a calcium carbonate structure in the saccule and utricle of the ear (PubMed:21655225, PubMed:24748133, PubMed:29076638). Acts as a scaffold for biomineralization: sequesters calcium and forms interconnecting fibrils between otoconia that are incorporated into the calcium crystal structure (PubMed:21655225, PubMed:24748133, PubMed:29076638). Together with OC90, modulates calcite crystal morphology and growth kinetics (PubMed:24748133). Homooligomer; disulfide-linked; probably forms homotrimers (PubMed:20856818, PubMed:24748133, PubMed:29076638). Interacts with OC90 (PubMed:17300776, PubMed:20856818, PubMed:21655225). Interacts with CBLN1 (PubMed:20856818). Localized in both the surrounding otoconial matrix and otoconia. Expressed in the organic matrix of otoconia (at protein level) (PubMed:17300776, PubMed:22841569). Expressed in neonatal sensory epithelium of vestibular utricle and saccule and also in otoconia (PubMed:21655225). The C1q domain mediates calcium-binding. Not N-glycosylated. Belongs to the OTOL1 family.