CSNK1E/CK1e

Twin to CK1δ, casein kinase 1 epsilon (CK1ε, gene CSNK1E) shares the δ/ε branch of the CK1 family and phosphorylates circadian PER proteins, setting clock period and phase. Genetic studies link CSNK1E variation to diurnal preference and to bipolar or affective disorders, and CK1ε, like CK1δ, phosphorylates tau and α-synuclein, implicating it in neurodegeneration. The kinase is broadly expressed, associates with microtubules and the cytoskeleton, and participates in Wnt signaling and vesicular trafficking. CK1ε can be regulated by autophosphorylation of its C-terminal tail, which distinguishes its control from that of the constitutively active CK1α isoforms.