Ca2+/CalmodulinDependent Protein Kinase II (CaM Kinase II) is a multifunctional calcium and calmodulindependent protein kinase that mediates cellular responses to a wide variety of intercellular signals. CaM Kinase II has been shown to regulate diverse cellular functions including synaptic plasticity, neurotransmitter synthesis and release, gene expression, ion channel function, carbohydrate metabolism, cytoskeletal function, and Ca2+homeostasis. Phosphorylation of Thr286 on the kinase produces an autonomously active form of CaM Kinase II. Autophosphorylation of Thr305 inhibits the activity CaM Kinase II. Phosphorylation at this site appears to reduce the association of CaM Kinase II with the PSD and reduce LTP and learning.