Cytokine-inducible SH2-containing protein (CISH)

SOCS family proteins form part of a classical negative feedback system that regulates cytokine signal transduction. CIS is involved in the negative regulation of cytokines that signal through the JAK-STAT5 pathway like erythropoietin, prolactin and interleukin 3 (IL3) receptor.

Inhibits STAT5 trans-activation by curbing its tyrosine phosphorylation. May be a substrate- recognition element 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 (By similarity).