CSNK1D is a member of the casein kinase I (CKI) gene family whose members have been implicated in the control of cytoplasmic and nuclear processes, including DNA replication and repair. This protein is highly similar to the mouse and rat CK1 delta homologs. Two transcript variants encoding different isoforms have been found for this gene. Recombinant human CSNK1D protein, fused to His-tag at N-terminus, was expressed in E.coli.