Overview:

JAK1 is a member of the Janus family of tyrosine kinases which are involved in cytokine receptor-mediated intracellular signal transduction (1). Upon stimulation by cytokines, JAK1 undergoes autophosphorylation. In turn, activated JAK1 is responsible for phosphorylating several signaling proteins, including STATs. Phosphorylated STATs dimerize and translocate to the nucleus where they regulate transcription of genes involved in growth, survival and differentiation. Phosphorylation of JAK1 at Tyr1022 and Tyr1023 is associated with cells that are undergoing proliferation (2).