Calcium functions as a second messenger and is involved in the regulation of a multitude of cellular physiological processes.
Calcium Signaling Target Files
The main mechanisms for elevating intracellular Ca2+ involve:
- Calcium entry through voltage- or ligand-gated calcium channels in the plasma membrane
- Ryanodine receptor- and IP3 receptor-mediated calcium release from the sarcoplasmic reticulum
- Na+/Ca2+ exchange in the mitochondrial membrane
The main mechanisms for removing calcium from the cytoplasm involve:
The diagram below summarizes the main cellular Ca2+ transport pathways, and some examples of the key sites for pharmacological manipulation.
The Major Cellular Ca2+ Transport Pathways
Ca2+ movements are highlighted in orange, while the gradients and stimuli that drive Ca2+ movement are indicated in blue text. Pharmacological agents are indicated in green text. The lefthand side of the diagram illustrates the processes that decrease [Ca2+]i, while the righthand side shows pathways that elevate cytosolic Ca2+. The elongated ellipses represent endoplasmic reticulum; the short ellipses represent mitochondria. Abbreviations include: cADPR - cyclic ADP ribose, Icrac - the capacitative calcium entry current; L/VGCC - ligand/voltage gated calcium channel.