CK1g2, Active

CK1?2 is a member of the CK1 family of serine/threonine protein kinases which play an important role in diverse cell processes, including DNA replication and repair. CK1?2 is a ubiquitously expressed cytoplasmic kinase that can interact and phosphorylate the metastatic tumor antigen 1 short form (MTA1s) co-localizing it in the cytoplasm (1). Phosphorylated MTA1s then sequesters the estrogen receptor-alpha in the cytoplasm of breast cancer cells. CK1?2 hyperphosphorylates the ceramide transfer protein CERT leading to a decrease in de novo sphingomyelin synthesis. The reduction in synthesis of sphingomyelin is reversed by the expression of CERT mutants that are not hyperphosphorylated (2).