Suppressors of Cytokine Signaling

Synonyms

SOCS

Definition

Suppressors of cytokine signaling (SOCS) and the cytokine-inducible SH2 protein CIS regulate the responses of various cells to Interleukins and other cytokines. They are rapidly induced after treatment with a cytokine. SOCS prevent prolonged activation of the signaling pathway of Janus kinase (JAK)/signal transducer and activator of transcription (STAT).

Characteristics

The SOCS/CIS family has eight members: SOCS-1, -2, -3, -4, -5, -6, -7, and CIS. They are composed of an amino-terminal domain of variable length, central SH2 domain, and a carboxy-terminal 40-amino-acid module known as SOCS box. Expression and function of SOCS-1, -2, -3 and CIS were characterized in most studies.

SOCS-1 and SOCS-3 downregulate JAK tyrosine kinase activity due to the presence of an inhibitory region in their amino-terminal domain. SOCS-1 could bind directly to JAK kinase through its SH2 domain, whereas SOCS-3 SH2 domain binds the signal-transduction subunit gp130 of a cytokine...