In vivo and in vitro analysis of starmaker activity in zebrafish otolith biomineralization.

Otoliths are one of the biominerals whose formation is highly controlled by proteins. The first protein discovered to be involved in otolith biomineralization in zebrafish was starmaker (Stm). Previously, Stm was shown to be responsible for the preferential formation of aragonite, a polymorph of calcium carbonate, in otoliths. In this work, proteomic analysis of adult zebrafish otoliths was performed. Stm is the only highly phosphorylated protein found in our studies. Besides previously studied otolith proteins, we discovered several dozens of unknown proteins that reveal the likely mechanism of biomineralization. A comparison of aragonite and vaterite otoliths showed similarities in protein composition. We observed the presence of Stm in both types of otoliths. In vitro studies of 2 characteristic Stm fragments indicated that the DS-rich region has a special biomineralization activity, especially after phosphorylation.-Kalka, M., Markiewicz, N., Ptak, M., Sone, E. D., Ożyhar, A., Dobryszycki, P., Wojtas, M. In vivo and in vitro analysis of starmaker activity in zebrafish otolith biomineralization.