Cytokine signaling mediated by the JAK-STAT pathway plays essential roles in differentiation, maturation, proliferation and apoptosis of a various types of cells. Suppressor of cytokine signaling (SOCS) proteins are negative feedback regulators of the JAK-STAT signaling pathway. SOCS1 and SOCS3 are potent inhibitors of JAKs and can play pivotal roles in inflammation, as well as in the development and progression of cancers []. All SOCS share a central SH2 domain and a C-terminal SOCS box, but only SOCS1 and SOCS3 possess a kinase inhibitory region immediately upstream of the central SH2 [].SOCS2 is necessary for normal growth regulation []. It appears to be a negative regulator in the growth hormone/IGF1 signaling pathway [, ].
