Biomineralization controlled by Otolin-1

Formation of the biomineral structures in the inner ear (otoliths and smaller, but having the same function otoconia) is tightly linked to the formation of organic matrix framework, among which the
otolin-1, a short collagen-like protein, is one of its major components. The published work examines the activity of recombinant fish (Danio) and human otolin-1 on calcium carbonate bioinspired mineralization. Both proteins are embedded in the core of CaCO3 crystals formed through slow-diffusion mineralization process. Both of them influence the morphology, but do not cause the polymorphic change of the mineral phase. The fish otolin-1 is also closely adhering to the crystal surface. The results suggest that also in natural biomineralization environment, the otolin-1 is not a passive scaffold but is directly involved in the regulation of morphology of the resulting calcium carbonate biocrystals.