The Diversity of Calcium Sensor Proteins in the Regulation of Neuronal Function

Calcium signaling in neurons as in other cell types mediates changes in gene expression, cell growth, development, survival, and cell death. However, neuronal Ca2+ signaling processes have become adapted to modulate the function of other important pathways including axon outgrowth and changes in synaptic strength. Ca2+ plays a key role as the trigger for fast neurotransmitter release. The ubiquitous Ca2+ sensor calmodulin is involved in various aspects of neuronal regulation. The mechanisms by which changes in intracellular Ca2+ concentration in neurons can bring about such diverse responses has, however, become a topic of widespread interest that has recently focused on the roles of specialized neuronal Ca2+ sensors. In this article, we summarize synaptotagmins in neurotransmitter release, the neuronal roles of calmodulin, and the functional significance of the NCS and the CaBP/calneuron protein families of neuronal Ca2+ sensors.