This gene encodes a member of the casein kinase I (CKI) family of serine/threonine protein kinases. A highly similar human protein regulates an array of cellular processes by influencing the Wnt and hedgehog signaling pathways. The encoded protein may also be involved in the regulation of apoptosis, circadian rhythm, microtubule dynamics, chromosome segregation, and p53-mediated effects on growth. Alternatively spliced transcript variants encoding different isoforms have been described. [provided by RefSeq].