Rabbit Anti-Human JAK2 monoclonal antibody for ICC, IF, WB. Janus Activating Kinase (JAK) is a number of related tyrosine kinases involved in cytoplasmic signal transduction. In response to a varitety of cytokine or related factors (e.g., interferon, interleukins), JAKs are activated via phosphorylation at 2 adjacent tyrosine residues. The activation of JAKs can lead to the phosphorylation of STAT (signal transducers and activatiors of transcription) proteins, which dimerize and translocate to the nucleus. Once translocated to the nucleus, the STAT proteins can modify transcription of numerous genes, including interferon-stimulated genes. JAK2 is required for the IFN gamma-receptor complex initiation and JAK1 functions as an amplifier. However, active JAK1 may be required for complex responses. Some studies have suggested that the role of JAK2 might be performed by Tyk2 and JAK3, if they were positioned correctly within the IFN gamma-receptor complex.