title: The suppressors of cytokine signalling (SOCS).
abstract: Members of the SOCS (suppressor of cytokine signalling) family of proteins play key roles in the negative regulation of cytokine signal transduction. A series of elegant biochemical and molecular biological studies has revealed that these proteins act in a negative feedback loop, inhibiting the cytokine-activated Janus kinase/signal transducers and activators of transcription (JAK/ STAT) signalling pathway to modulate cellular responses. Although structurally related, the precise mechanisms of SOCS-1, SOCS-3 and cytokine-inducible SH2-containing protein (CIS) action vary. Direct interaction of SOCS SH2 domains with the JAK kinases or cytokine receptors allows their recruitment to the signalling complex, where they inhibit JAK catalytic activity or block access of the STATs to receptor binding sites. The defining feature of the family, the C-terminal SOCS box domain, appears dispensable for these actions but is likely to play a key role in negative regulation of signalling by targeting molecules associated with the SOCS proteins for degradation. The relevance of SOCS-mediated regulation of cytokine responses has been brought into sharp focus by the dramatic phenotypes of mice lacking these regulators. Indispensable roles for members of this family have been identified in the regulation of interferon gamma, growth hormone and erythropoietin, and the absence of SOCS-1 or SOCS-3 is lethal in mice.
authors.affiliation: Division of Cancer and Hematology, The Walter and Eliza Hall Institute for Medical Research and the Cooperative Research Centre for Cellular Growth Factors, Royal Melbourne Hospital, Victoria, Australia.
authors.forename: B T
authors.initials: BT
authors.lastname: Kile
authors.forename: W S
authors.initials: WS
authors.lastname: Alexander
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D016207:Cytokines / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism; D007371:Interferon-gamma / Q000378:metabolism; D053613:Janus Kinase 1; D008025:Ligases / Q000737:chemistry / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D050794:STAT1 Transcription Factor; D015398:Signal Transduction / Q000502:physiology*; D000071222:Suppressor of Cytokine Signaling 1 Protein; D000071223:Suppressor of Cytokine Signaling 3 Protein; D050826:Suppressor of Cytokine Signaling Proteins; D015534:Trans-Activators / Q000378:metabolism; D014157:Transcription Factors; D025801:Ubiquitin / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases
chemical_list: D002352:Carrier Proteins; D016207:Cytokines; D004268:DNA-Binding Proteins; D011506:Proteins; D012097:Repressor Proteins; D050794:STAT1 Transcription Factor; C491590:Socs1 protein, mouse; C491411:Socs3 protein, mouse; C494080:Stat1 protein, mouse; D000071222:Suppressor of Cytokine Signaling 1 Protein; D000071223:Suppressor of Cytokine Signaling 3 Protein; D050826:Suppressor of Cytokine Signaling Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D025801:Ubiquitin; D007371:Interferon-gamma; D044767:Ubiquitin-Protein Ligases; D011505:Protein-Tyrosine Kinases; C507905:Jak1 protein, mouse; D053613:Janus Kinase 1; D008025:Ligases