This is calcium-dependent, phospholipid-dependent, serine- and threonine-specific enzyme. Activation of PKC by serotonin results in presynaptic facilitation of depressed sensory-to-motor neuron synapses, which is thought to underlie behavioral dishabituation. PKC is activated by diacylglycerol which in turn phosphorylates a range of cellular proteins. PKC also serves as the receptor for phorbol esters, a class of tumor promoters (By similarity). ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Binds 3 Ca(2+) ions per C2 domain. Activated by phosphatidylserine. Translocated to neuronal membranes. Belongs to the protein kinase superfamily. AGC Ser/Thr protein kinase family. PKC subfamily.