The product of this gene belongs to the Serine/Threonine protein kinase family, and to the Ca(2+)/calmodulin-dependent protein kinase subfamily. This protein plays a role in the calcium/calmodulin-dependent (CaM) kinase cascade by phosphorylating the downstream kinases CaMK1 and CaMK4. Seven transcript variants encoding six distinct isoforms have been identified for this gene. Additional splice variants have been described but their full-length nature has not been determined. The identified isoforms exhibit a distinct ability toundergo autophosphorylation and to phosphorylate the downstream kinases.