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. 2018 Jan 17;7:82. [Version 1] doi: 10.12688/f1000research.13167.1

Figure 1. Janus kinases (JAKs) and the cytokine receptor superfamily.

Figure 1.

Schematic representation of type I and type II cytokine receptor subfamilies based on the extracellular domain sequence homologies. The different JAKs (JAK1, JAK2, JAK3, and TYK2) are employed by each class of receptors, as indicated. Type I receptors can form homodimers (α/α), heterodimers (α/β), or oligomers (gp130/α/gp130);(α/β/γ), although the α chain is mainly responsible for cytokine binding. Cytokine receptor complexes composed of two or more different chains activate at least two different JAKs, while single-chain receptors such as homodimeric receptors activate JAK2 only (although TpoR/MPL and G-CSFR/CSF3R can also use TYK2 and JAK1, respectively). The myelopoiesis-related cytokine receptors are denoted in red, and the lymphopoiesis-related cytokines receptors are denoted in green.