Casein kinase 1: Complexity in the family.

The CK1 family of serine/threonine kinases regulates diverse cellular processes, through binding to and phosphorylation a myriad of protein substrates. CK1 prefers substrates primed by prior phosphorylation, and works closely with other kinases in the Wnt pathway. CK1 is itself regulated by posttranslational modification, including autophosphorylation. We provide a brief overview of the fundamentals of CK1 biology with an emphasis on scaffold binding and kinase regulation in Wnt signaling and circadian rhythms.