JAK Inhibitors: New Treatments for RA and beyond

Janus kinases are a family of intra-cellular tyrosine kinases that are activated after stimulation of several cell surface receptors by their specific growth factors, growth hormones, chemokines and cytokines. After activation, they phosphorylate STAT transcription factors, resulting in the transportation of these STATs to the nucleus and affecting expression of specific genes. These transduced cytokinemediated signals via the JAK-STAT pathway are pivotal for the downstream signaling of inflammatory responses and their desired, as well as pathologic affects. As such, JAK kinases are a critical conduit for translating information from a cell’s extracellular environment to its nucleus, resulting in gene expression profiles corresponding to these extracellular cues.