Interleukin-21 receptor complex (IL-21R complex)

The Interleukin-21 receptor complex is a heterodimeric receptor composed of the interleukin-21 receptor (IL-21R) and the common gamma chain (IL2RG/γc), both of which are type I cytokine receptors[1][2][3][5][7]. The complex mediates signaling in response to binding of the cytokine interleukin-21 (IL-21), which leads to activation of JAK-STAT, PI3K-AKT, and MAPK pathways that regulate diverse immune processes including T cell and B cell differentiation, NK cell function, and inflammation[2][6][8][10]. The IL-21R complex is a key therapeutic target for modulation of immune responses in cancer, autoimmune diseases, infectious diseases, and cardiovascular pathology, due to its central role in immune cell proliferation, differentiation, and survival[6][8][4]. Structural studies reveal the receptor consists of extracellular fibronectin type III domains and features a signature WSXWS motif important for receptor architecture and function[1][3][5][9]. Current therapeutic interventions focus on antagonizing IL-21 or its receptor to downregulate pathological immune activation, with several monoclonal antibodies in clinical development.

Other names

Interleukin-21 receptor–common gamma chain complexIL-21R–gammaC complexIL21–IL21R–IL2RG complexIL-21 receptor heterodimer

Cytokine signaling inhibition (by receptor or ligand blockade); JAK-STAT pathway inhibition; Downregulation of immune cell proliferation and function