Fig. 2

Effector cytokines can stimulate transcription of proinflammatory signals through the Janus kinase–signal transducers and activators of transcription (JAK-STAT) signalling pathway. Intracellular JAK and tyrosine kinase (TYK) proteins are activated when a ligand binds to its receptor which induces phosphorylation and activation, which in turn activate STAT proteins. The STAT proteins dimerize and translocate to the nucleus where they bind STAT-specific response elements in target gene promotors and regulate gene transcription; including proinflammatory signals. JAK inhibitors (e.g. baricitinib and tofacitinib) are able to abrogate signalling cascades from more than one effector cytokine pathway