CK1 (Casein kinase I) is characterized by its Ser/Thr protein kinase catalytic activity on phoshorylation of casein in vitro in a cycle AMP-independent manner. Six isoforms and CK1-like kinase have been identified in this family. Sequence analysis shows that all members share a N-terminal conserved kinase catalytic domain and a variable C-terminal sequence. Several potential regulatory mechanisms for CK1s have been described including activation via phosphorylation of PKA, 14-3-3 binding and autoinhibition. CK1s are involved in a variety of cellular processes via phosphorylation of a large range of substrates, for instance, stabilizing AIB1 and increasing Erα transcriptional activity, facilitating CK1α/FADD/CaM complex assembly for proper cell cycle progression, reducing DNA-binding activity of Dnmt1, blocking nuclear export and so on. (1)

Reference
1. Cheong, J.K. and Virshup, D.M. (2011) Casein kinase 1: Complexity in the family. Int J Biochem Cell Biol, 43, 465-469. PMID: 21145983

    VRK (vaccinia related kinases) belong to CK1 family. Three members have been identified in human genome, known as VRK1, VRK2 and VRK3. Sequence alignment of VRKs shows that all VRKs share a similar ser/thr protein kinase catalytic domain. Human VRK1 and VRK3 also contain a nuclear localization signal region and VRK2 contain a transmembrane domain in its C-terminal. VRKs act as key activator for activation or stabilization of a variety of transcription factors, including p53, ATF1, c-Jun and CREB. In addition, VRKs play an important role in regulation of cellular processes, including stress response and patterning of chromatin modifications (1).

Reference
1. Klerkx, E.P., Lazo, P.A. and Askjaer, P. (2009) Emerging biological functions of the vaccinia-related kinase (VRK) family. Histol Histopathol, 24, 749-759. PMID: 19337973

    Worm10 belong to CK1 family and it's a specific kinase family to Caenorhabditis elegans. At least 2 members have been predicted in Caenorhabditis elegans genome. The functions of the members remain to be studied (1).

Reference
1. Manning, G., Whyte, D.B., Martinez, R., Hunter, T. and Sudarsanam, S. (2002) The protein kinase complement of the human genome. Science, 298, 1912-1934. PMID: 12471243

    Worm7 belong to CK1 family and it's a specific kinase family to Caenorhabditis elegans. At least 2 members have been predicted in Caenorhabditis elegans genome. The functions of the members remain to be studied (1).

Reference
1. Manning, G., Whyte, D.B., Martinez, R., Hunter, T. and Sudarsanam, S. (2002) The protein kinase complement of the human genome. Science, 298, 1912-1934. PMID: 12471243

    Worm9 belong to CK1 family and it's a specific kinase family to Caenorhabditis elegans. At least 2 members have been predicted in Caenorhabditis elegans genome. The functions of the members remain to be studied (1).

Reference
1. Manning, G., Whyte, D.B., Martinez, R., Hunter, T. and Sudarsanam, S. (2002) The protein kinase complement of the human genome. Science, 298, 1912-1934. PMID: 12471243