TYK2 Protein, Human (Active, Biotinylated, sf9, His, Flag, Avi)

TYK2 is a non-receptor tyrosine kinase involved in signaling by various cytokines and interferons, regulating cell growth, development, migration, and innate/adaptive immunity. It plays both structural and catalytic roles in interleukin and interferon (e.g., IFN-alpha/beta) signaling. TYK2 associates with heterodimeric cytokine receptor complexes and activates STAT family members, including STAT1, STAT3, STAT4, or STAT6. These receptor complexes consist of (1) a TYK2-associated receptor chain (e.g., IFNAR1, IL12RB1, IL10RB, or IL13RA1) and (2) a second receptor chain bound to either JAK1 or JAK2. Upon cytokine binding, TYK2 phosphorylates and activates receptors, creating docking sites for STAT proteins. Recruited STATs are then phosphorylated by TYK2 (or JAK1/JAK2 on the second receptor chain), forming homo- or heterodimers that translocate to the nucleus to regulate cytokine/growth factor-responsive genes. Additionally, TYK2 negatively regulates STAT3 activity by promoting phosphorylation at a specific tyrosine site distinct from its signaling site.