Identification of a gp130 Cytokine Receptor Critical Site Involved in Oncostatin M Response

Christophe Olivier,Patrick Auguste,Marie Chabbert,Eric Lelièvre,Sylvie Chevalier,Hugues Gascan

doi:10.1074/jbc.275.8.5648

Christophe Olivier, Patrick Auguste + Show 4 more

Open Access

https://doi.org/10.1074/jbc.275.8.5648

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Abstract

Gp130 cytokine receptor is involved in the formation of multimeric functional receptors for interleukin-6 (IL-6), IL-11, leukemia inhibitory factor (LIF), oncostatin M (OSM), ciliary neurotrophic factor, and cardiotrophin-1. Cloning of the epitope recognized by an OSM-neutralizing anti-gp130 monoclonal antibody identified a portion of gp130 receptor localized in the EF loop of the cytokine binding domain. Site-directed mutagenesis of the corresponding region was carried out by alanine substitution of residues 186-198. To generate type 1 or type 2 OSM receptors, gp130 mutants were expressed together with either LIF receptor beta or OSM receptor beta. When positions Val-189/Tyr-190 and Phe-191/Val-192 were alanine-substituted, Scatchard analyses indicated a complete abrogation of OSM binding to both type receptors. Interestingly, binding of LIF to type 1 receptor was not affected, corroborating the notion that in this case gp130 mostly behaves as a converter protein rather than a binding receptor. The present study demonstrates that positions 189-192 of gp130 cytokine binding domain are essential for OSM binding to both gp130/LIF receptor beta and gp130/OSM receptor beta heterocomplexes.

Highlights

Depending on the identity of the activating ligand, gp130 can either homodimerize in the presence of IL-6 [13] and IL-11 [14] or associate with a related type I cytokine receptor, LIFR␤ [15], when recruited by leukemia inhibitory factor (LIF), oncostatin M (OSM) [16], ciliary neurotrophic factor
This is the case for the signal transducers and activators of transcription (STAT) family of transcription factors, which bind to the receptors before being activated and migrate into the nucleus, where they initiate the transcription of the IL-6 family of target genes [24, 25]
The results show that VY189/190AA and FV191/192AA mutations induced a dramatic reduction of OSM binding to gp130/LIFR␤ or gp130/ OSMR␤ receptor complexes

Summary

Introduction

Depending on the identity of the activating ligand, gp130 can either homodimerize in the presence of IL-6 [13] and IL-11 [14] or associate with a related type I cytokine receptor, LIFR␤ [15], when recruited by LIF, OSM [16], ciliary neurotrophic factor. Beside the common LIF/OSM receptor complex made of gp130/LIFR␤, OSM is able to activate a specific heterodimeric receptor, implicating an association of gp130 with OSMR␤ [19] For some of these receptor complexes a third additional ␣ component leading to an increased specificity and affinity to one given ligand is required to generate fully functional receptors. Phosphorylation of tyrosine residues located in the intracellular domain of the cytokine receptors will serve as docking sites for adapters and transcription factors This is the case for the signal transducers and activators of transcription (STAT) family of transcription factors, which bind to the receptors before being activated and migrate into the nucleus, where they initiate the transcription of the IL-6 family of target genes [24, 25]. A recent study reported that amino acids Tyr-190 and Phe-191 located in the EF loop are prevalent for the interaction of gp130 with IL-6 and IL-11 when associated with their respective ␣ receptor components [35]

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Results

Conclusion