And exposure of these hydrophobic regions on Calmodulen allows the calcium calmodulent complex to go on and bind to many important enzymes and affect the molecules. And one important enzyme, one important molecule that Calmodulen binds to is the calmodulendependent protein kinase, which basically depends on this complex here. So calcium being a secondary messenger, once it's released from the lumen and goes into the cytoplasm, it binds onto calmodulen and then informs the calcium calmojulin complex, which is a stimulating complex because it goes on and binds onto the calmodul independent protein kinase, which is activated and then goes on to phosphorylate many different types of enzymes and that stimulates many different types of pathways. So calmodulin is a regulatory protein that is used to detect changes in calcium ion concentrations. If the cytoplasmic concentration of calcium ions raises to about 500 nm, so five times what it should be under steady state conditions, calmodulant will begin binding these calcium ions. And a single calmodulant, because it contains a few of these, can actually bind four individual calcium mines.