Protein Red (IK)

Protein Red (IK) is a human nuclear protein encoded by the IK gene on chromosome 5, notable for its RED repeat motif—a stretch of repeated arginine, glutamic acid, and aspartic acid residues. It functions as an auxiliary spliceosomal protein, regulating alternative splice sites in specific pre-mRNA targets and is crucial for mitotic cell cycle progression by recruiting spindle assembly checkpoint proteins to kinetochores. Its proper activity is needed for normal pre-mRNA splicing during cell division and for viral mRNA processing in infections like influenza A. Though initially described as a "cytokine" and as a down-regulator of HLA class II expression, its direct secreted cytokine activity is not established; it mainly acts as a nuclear regulatory protein. Mutations or dysregulation are associated with several pathologies, including cancer and inherited disorders. There are currently no approved drugs directly targeting Protein Red/IK, and its biomarker or therapeutic use remains theoretical.

Other names

Cytokine IKIK factorProtein RERREDRERCSA2Chondrosarcoma-associated protein 2Down-regulator of HLA IIRD elementprer proteinprotein RedIK cytokine