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Association and activation of Jak-Tyk kinases by CNTF-LIF-OSM-IL-6 beta receptor components
N Stahl1, T G Boulton, T Farruggella
1Regeneron Pharmaceuticals, Inc., Tarrytown, NY 10591.
Abstract:
A recently defined family of cytokines, consisting of ciliary neurotrophic factor (CNTF), leukemia inhibitory factor (LIF), oncostatin M (OSM), and interleukin-6 (IL-6), utilize the Jak-Tyk family of cytoplasmic tyrosine kinases. The beta receptor components for this cytokine family, gp130 and LIF receptor beta, constitutively associate with Jak-Tyk kinases. Activation of these kinases occurs as a result of ligand-induced dimerization of the receptor beta components. Unlike other cytokine receptors studied to date, the receptors for the CNTF cytokine family utilize all known members of the Jak-Tyk family, but induce distinct patterns of Jak-Tyk phosphorylation in different cell lines.
Insights
Cytokines like CNTF, LIF, OSM, and IL-6 activate Jak-Tyk kinases through receptor dimerization. This cytokine family uniquely employs all Jak-Tyk kinases, inducing distinct phosphorylation patterns in cells.
Area of Science:
- Cellular signaling pathways
- Cytokine receptor activation
- Signal transduction mechanisms
Background:
- A specific cytokine family, including ciliary neurotrophic factor (CNTF), leukemia inhibitory factor (LIF), oncostatin M (OSM), and interleukin-6 (IL-6), has been identified.
- These cytokines are known to interact with the Janus kinase-Tyrosine kinase (Jak-Tyk) family of cytoplasmic tyrosine kinases.
- The beta receptor components, gp130 and LIF receptor beta, are constitutively associated with Jak-Tyk kinases.
Purpose of the Study:
- To investigate the mechanism of Jak-Tyk kinase activation by the CNTF cytokine family.
- To explore the differential utilization and phosphorylation patterns of Jak-Tyk kinases induced by this cytokine family across various cell types.
Main Methods:
- Ligand-induced receptor dimerization assays.
- Analysis of Jak-Tyk kinase association with receptor beta components.
- Phosphorylation pattern analysis of Jak-Tyk kinases in different cell lines upon cytokine stimulation.
Main Results:
- Ligand binding triggers dimerization of receptor beta components, leading to Jak-Tyk kinase activation.
- The CNTF cytokine family engages all known members of the Jak-Tyk kinase family.
- Distinct and cell-specific patterns of Jak-Tyk phosphorylation were observed, differentiating this family from other cytokine receptors.
Conclusions:
- The CNTF cytokine family employs a unique signaling mechanism involving the comprehensive activation of the Jak-Tyk kinase family.
- The observed distinct phosphorylation patterns suggest cell-specific downstream effects and functional outcomes mediated by these cytokines.
- This highlights the complexity and specificity of cytokine-mediated cellular responses.