Figure 1.

Overview of calcium signaling. Calcium release from the extracellular space or intracellular compartments into the cytosol activates calmodulin, which in turn binds to CaMKK and CaMK proteins. Phosphorylation of CaM-binding proteins via autophosphorylation or upstream kinases further activates, or in some cases inhibits their activity toward downstream signaling proteins and transcription factors. The CaMKK inhibitor, STO-609, can also stall these downstream processes.