Potent and specific cellular inhibitor of CaM-kinase II (CAMK2) (PubMed:11444830). Traps Ca(2+)/calmodulin on CAMK2 (By similarity). Interacts with CAMK2A and CAMK2B in the presence of Ca(2+)/calmodulin or after autophosphorylation. Excluded from nucleus when coexpressed with activated CAMK2. Highly Expressed in keyhole limpet hemocyanin-stimulated dendritic cell (DC) and weakly expressed in unstimulated mature and immature DC (PubMed:11444830). Highly expressed in kidney and liver (PubMed:11444830). Moderately expressed in heart, skeletal muscle, and placenta (PubMed:11444830). Weakly expressed in the small intestine (PubMed:11444830). Belongs to the CAMK2N family.