Otolin-1, an otolith- and otoconia-related protein, controls calcium carbonate bioinspired mineralization

• Published in: Biochimica et biophysica acta. General subjects Vol. 1867; no. 5; p. 130327
• Main Authors: Bielak, Klaudia, Benkowska-Biernacka, Dominika, Ptak, Maciej, Stolarski, Jarosław, Kalka, Marta, Ożyhar, Andrzej, Dobryszycki, Piotr
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.05.2023
• Subjects: Animals; Biocrystal; Biomineral; Biomineralization; Calcium carbonate; Calcium Carbonate - chemistry; Danio rerio; electron microscopy; Extracellular Matrix Proteins - metabolism; family; fluorescence microscopy; Humans; mineralization; Otoconia; Otolin-1; Otolithic Membrane - chemistry; Otolithic Membrane - metabolism; Otoliths; Raman spectroscopy; Zebrafish - metabolism; Otoconia; Otoliths; Biomineral; Calcium carbonate; Otolin-1; Biomineralization; Biocrystal
• ISSN: 0304-4165; 1872-8006; 1872-8006
• DOI: 10.1016/j.bbagen.2023.130327

Otoliths and otoconia are calcium carbonate biomineral structures that form in the inner ear of fish and humans, respectively. The formation of these structures is tightly linked to the formation of an organic matrix framework with otolin-1, a short collagen-like protein from the C1q family as one of its major constituents. In this study, we examined the activity of recombinant otolin-1 originating from Danio rerio and Homo sapiens on calcium carbonate bioinspired mineralization with slow-diffusion method and performed crystals characterization with scanning electron microscopy, two-photon excited fluorescence microscopy, confocal laser scanning microscopy and micro-Raman spectroscopy. We show that both proteins are embedded in the core of CaCO3 crystals that form through the slow-diffusion mineralization method. Both of them influence the morphology but do not change the polymorphic mineral phase. D.rerio otolin-1 also closely adheres to the crystal surface. The results suggest, that otolin-1 is not a passive scaffold, but is directly involved in regulating the morphology of the resulting calcium carbonate biocrystals. [Display omitted] •Otolin-1 influences the morphology of calcium carbonate crystals.•In bioinspired mineralization, otolin-1 creates a nucleation core of calcite crystals.•Otolin-1 provides new mineralization planes for calcite growth.