Figure 4.

Alignment of Box1 and Box2 motifs from Janus kinase (JAK)-interacting cytokine receptors. The juxtamembrane intracellular sequences from all known signaling receptors that interact with JAKs were aligned by their Box1 proline motifs. Receptors are grouped by class I and class II, followed by subgroupings by either the JAK they interact with (class II) or by subfamily (class I). Due to the low sequence homology between receptors, the alignments were produced by hand, and the residues colored in order to highlight some of the shared features of the receptors. Hydrophobic residues within the Box1 region are colored in blue and prolines in yellow. For the Box2 region, putative four-residue hydrophobic motifs (aliphatic-X-aliphatic-X) are colored in blue, with glutamate residues three to seven residues N-terminal to these motifs are colored in purple. Receptors with known structures (IFNAR1, IFNLR1, and IL10RA) are marked with a star.