Interleukin-6-type cytokine signalling through the gp130/Jak/STAT pathway.
The family of cytokines signalling through the common receptor subunit gp130 comprises interleukin (IL)-6, IL-11, leukaemia inhibitory factor, oncostatin M, ciliary neurotrophic factor and cardiotrophin-1. These so-called IL-6-type cytokines play an important role in the regulation of complex cellular processes such as gene activation, proliferation and differentiation. The current knowledge on the signal-transduction mechanisms of these cytokines from the plasma membrane to the nucleus is reviewed. In particular, we focus on the assembly of receptor complexes after ligand binding, the activation of receptor-associated kinases of the Janus family, and the recruitment and phosphorylation of transcription factors of the STAT family, which dimerize, translocate to the nucleus, and bind to enhancer elements of respective target genes leading to transcriptional activation. The important players in the signalling pathway, namely the cytokines and the receptor components, the Janus kinases Jak1, Jak2 and Tyk2, the signal transducers and activators of transcription STAT1 and STAT3 and the tyrosine phosphatase SHP2 [SH2 (Src homology 2) domain-containing tyrosine phosphatase] are introduced and their structural/functional properties are discussed. Furthermore, we review various mechanisms involved in the termination of the IL-6-type cytokine signalling, namely the action of tyrosine phosphatases, proteasome, Jak kinase inhibitors SOCS (suppressor of cytokine signalling), protein inhibitors of activated STATs (PIAS), and internalization of the cytokine receptors via gp130. Although all IL-6-type cytokines signal through the gp130/Jak/STAT pathway, the comparison of their physiological properties shows that they elicit not only similar, but also distinct, biological responses. This is reflected in the different phenotypes of IL-6-type-cytokine knock-out animals.
Institut für Biochemie, RWTH Aachen, Universitätsklinikum, Pauwelsstrasse 30, D-52057 Aachen, Germany. Heinrich@RWTH-Aachen.de
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Heinrich
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Behrmann
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Müller-Newen
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Schaper
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Graeve
D000818:Animals; D015703:Antigens, CD / Q000378:metabolism*; D002454:Cell Differentiation; D002455:Cell Division; D002462:Cell Membrane / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D050822:Cytokine Receptor gp130; D016207:Cytokines / Q000737:chemistry / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005786:Gene Expression Regulation; D006801:Humans; D015850:Interleukin-6 / Q000502:physiology*; D008562:Membrane Glycoproteins / Q000378:metabolism*; D008958:Models, Molecular; D011487:Protein Conformation; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D018121:Receptors, Cytokine / Q000737:chemistry / Q000502:physiology*; D015398:Signal Transduction; D015534:Trans-Activators / Q000378:metabolism*; D015533:Transcriptional Activation
D015703:Antigens, CD; D016207:Cytokines; D004268:DNA-Binding Proteins; C494199:IL6ST protein, human; D015850:Interleukin-6; D008562:Membrane Glycoproteins; D018121:Receptors, Cytokine; D015534:Trans-Activators; D050822:Cytokine Receptor gp130; D011505:Protein-Tyrosine Kinases