VRK3 Full-Length MS Protein Standard (NP_057524), Labeled with [U- 13C6, 15N4]-L-Arginine and [U- 13C6, 15N2]-L-Lysine, was produced in human 293 cells (HEK293) with fully chemically defined cell culture medium to obtain incorporation efficiency at Creative-Proteomics. This gene encodes a member of the vaccinia-related kinase (VRK) family of serine/threonine protein kinases. In both human and mouse, this gene has substitutions at several residues within the ATP binding motifs that in other kinases have been shown to be required for catalysis. In vitro assays indicate the protein lacks phosphorylation activity. The protein, however, likely retains its substrate binding capability. This gene is widely expressed in human tissues and its protein localizes to the nucleus. Alternative splicing results in multiple transcripts encoding different isoforms.