Interleukin-4 (IL-4) (B-cell stimulatory factor 1) (BSF-1) (Binetrakin) (Lymphocyte stimulatory factor 1) (Pitrakinra)
1_MGLTS 6_ QLLPP 11_ LFFLL 16_ ACAGN 21_ FVHGH 26_ KCDIT 31_ LQEII 36_ KTLNS 41_ LTEQK 46_ TLCTE 51_ LTVTD 56_ IFAAS 61_ KNTTE 66_ KETFC 71_ RAATV 76_ LRQFY 81_ SHHEK 86_ DTRCL 91_ GATAQ 96_ QFHRH 101_ KQLIR 106_ FLKRL 111_ DRNLW 116_ GLAGL 121_ NSCPV 126_ KEANQ 131_ STLEN 136_ FLERL 141_ KTIMR 146_EKYSK
1: Cytokine secreted primarily by mast cells, T-cells, eosinophils, and basophils that plays a role in regulating antibody production, hematopoiesis and inflammation, and the development of effector T-cell responses (PubMed:1993171, PubMed:3016727). Induces the expression of class II MHC molecules on resting B-cells. Enhances both secretion and cell surface expression of IgE and IgG1 (PubMed:1993171). Also regulates the expression of the low affinity Fc receptor for IgE (CD23) on both lymphocytes and monocytes (PubMed:2521231). Positively regulates IL31RA expression in macrophages. Stimulates autophagy in dendritic cells by interfering with mTORC1 signaling and through the induction of RUFY4. In addition, plays a critical role in higher functions of the normal brain, such as memory and learning (By similarity). Upon binding to IL4, IL4R receptor dimerizes either with the common IL2R gamma chain/IL2RG to produce the type 1 signaling complex, located mainly on hematopoietic cells, or with the IL13RA1 to produce the type 2 complex, which is also expressed on nonhematopoietic cells (PubMed:10219247, PubMed:11526337, PubMed:18243101). Engagement of both types of receptors initiates JAK3 and to a lower extend JAK1 phosphorylation leading to activation of the signal transducer and activator of transcription 6/STAT6 (PubMed:7721895)