Three papers were signed at a joint CSIC and the University of Salamanca describe the identification and characterization of a new family of serine-threonine kinases of human carcinoma, in the course of evolution, separated from the branch that subsequently caused the casein kinases. The catalytic domain of this new family VRK (vaccinia-related kinases) is related to the vaccinia virus B1R protein. 

There are three VRK kinases in human carcinoma, but only 1 and 2 are catalytically active; of them, VRK1 is the best characterized. It is located within the nucleus, although in certain circumstances, is also present in the cytosol and the nucleolus. Within the nucleus, phosphorylates transcription factors such as p53, c-Jun and ATF2. Although its substrates are proteins involved in stress response, the VRK1 involved in a physiological pathway of the cell, not in response to damage.
Can cooperate with the path of the Jun kinase (JNK) in the phosphorylation of target sites in c-Jun, by which it competes. Phosphorylation of ATF2 factor is a cooperative action between VRK1 and JNK, both of which act on different residues within the same region with the same functional consequences. Moreover, VRK1 also phosphorylates p53 factor and contributes to its stabilization and accumulation. The factor loses its ability to interact with hdm2 and binds to the acetyltransferase p300 or MDMX (protein double minute 4). We have proposed a model of performance under normal conditions, in which VRK1 maintain baseline levels of p53, enough to damage situations common in cell life. This stabilized baseline would initiate a response in case of severe stress such as exposure to chemotherapy or radiation therapy, traditionally used stimuli.