This is an F2 lobe domain consisting of an acyl-CoA binding protein fold found in FERM region of Jak-family tyrosine kinases []. Multidomain JAK molecules interact with receptors through their FERM and SH2-like domains, triggering a series of phosphorylation events, resulting in the activation of their kinase domains []. Overall, the FERM region maintains the typical three-lobed architecture, with an F1 lobe consisting of a ubiquitin-like fold, an F2 lobe consisting of an acyl-CoA binding protein fold, and an F3 lobe consisting of a pleckstrin-homology (PH) fold. JAK1 FERM-F2 domain has been shown to act as the interaction site for the IFNLR1 box1 motif (PxxLxF) of class II cytokine receptors which is essential for kinase activation [].
