Calcium Signaling in Cholangiocytes
Evidence suggests that Ca2+ is able to regulate such a wide range of cellular activities by the manners in which Ca2+ signals are encoded. For example, cells can encode signals using both amplitude modulation and frequency modulation of Ca2+ transients, and can even independently modulate Ca2+ signals in different regions of an individual cell. These general principles of Ca2+ signaling have been determined based on work involving a number of cell systems. Cholangiocytes are polarized epithelial cells, and receptors that link to Ca2+ signaling have been identified in both the apical and basolateral domain of the plasma membrane. The patterns by which Ca2+ increases over space and time are important components of Ca2+ signaling. For example, Ca2+ -mediated secretion depends upon spatial patterns such as Ca2+ gradients and waves in cell types as diverse as neurons, adrenal chromaffin cells, and exocrine pancreas.