IL4

Interleukin-4 (IL-4) is a secreted four-helix bundle cytokine of the IL-4/IL-13 family, produced primarily by Th2 cells, basophils, mast cells, eosinophils, and group 2 innate lymphoid cells (ILC2s). It functions as the master regulator of type 2 immunity by binding the IL-4 receptor alpha chain (IL4RA) and signaling through two receptor complexes: the type I complex (IL4RA/IL2RG) on hematopoietic cells, and the type II complex (IL4RA/IL13RA1) on non-hematopoietic and some hematopoietic cells. IL-4 signals canonically through JAK1/JAK3-STAT6, leading to GATA3 induction that drives Th2 differentiation, B cell class switch recombination to IgE and IgG4, MHC class II upregulation on B cells, and M2 macrophage polarization. IL-4 also activates IRS-2/PI3K pathways contributing to cell survival and proliferation. It is a central mediator of allergic inflammation, anti-helminth defense, and various immune regulatory processes. The protein has three disulfide bonds (Cys3-Cys127, Cys24-Cys65, Cys46-Cys99) and one N-glycosylation site (Asn62). An alternatively spliced isoform (IL-4delta2) lacking exon 2 acts as a natural antagonist.

Disorders

Relationship is the entry's genetic[].relationship_type. untyped means the entry has a genetic record for the gene but does not type it; its free-text association is shown instead.