Collagen-like protein, which provides an organic scaffold for otoliths onto the sensory epithelium of the inner ear (PubMed:15905077, PubMed:29076638). Acts as a scaffold for biomineralization by sequestering calcium (PubMed:29076638). Homooligomer; disulfide-linked; probably forms homotrimers (PubMed:29076638). Interacts with otomp (By similarity). Localized in both the surrounding otoconial matrix and otoconia. The C1q domain mediates calcium-binding. Belongs to the OTOL1 family.