Anti-Cark antibodies enable researchers to detect and measure the Cark antigen in biological samples. This target is a reported synonym of the TNNI3K gene, which encodes TNNI3 interacting kinase. This protein is known to function in protein phosphorylation, among other biological roles. The human version of Cark has a canonical amino acid length of 835 residues and a protein mass of 92.9 kilodaltons, although 4 isoforms have been identified. It is reported to be localized in the nucleus and cytoplasm of cells. Cark is a member of the TKL Ser/Thr protein kinase protein family.