Calcium Ion and Mineral Pathways in Biomineralization: A Perspective

Calcium transport from the environment to the final site of mineral deposition involves uptake from the water or the food into cells. Within the cells calcium ions are translocated to various organelles and vesicles where they accumulate, in such a way as to not raise the very low calcium concentrations in the cytosol. In various biomineralizing systems, the calcium is stored in vesicles as a highly disordered hence relatively soluble solid phase. The concentrated calcium phase is then translocated out of the cell to the site of mineralization. Additional pathways may involve transport through the vasculature as ions and possibly mineral from distant sites. Understanding calcium pathways is the foundation for not only better understanding biomineralization processes but also for better understanding calcium and its fundamental role in cell signaling.