SOCS family proteins form part of a classical negative feedback system that regulates cytokine signal transduction. May be a substrate-recognition component of a SCF-like ECS (Elongin BC-CUL2/5-SOCS-box protein) E3 ubiquitin-protein ligase complex which mediates the ubiquitination and subsequent proteasomal degradation of target proteins. Inhibits for instance EGF signaling by mediating the degradation of the EGF receptor/EGFR. Involved in the regulation of T-helper cell differentiation by inhibiting of the IL4 signaling pathway which promotes differentiation into the Th2 phenotype. Can also partially inhibit IL6 and LIF signaling. Protein modification; protein ubiquitination. Interacts with EGFR. Interacts with ELOB and ELOC; mediates EGFR ubiquitination and degradation (By similarity). Interacts with IL4R; inhibits IL4 signaling. Widely expressed. Expressed in TH1 but not TH2 cells. During embryonic development, expressed from mid-to-late gestation and in yolk sac. By a subset of cytokines including IL6 and LIF. The SOCS box domain mediates the interaction with the Elongin BC complex, an adapter module in different E3 ubiquitin ligase complexes. Phosphorylated. Phosphorylation is induced by EGF (By similarity).