Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10766746 | Biochemical and Biophysical Research Communications | 2008 | 6 Pages |
Abstract
Ligand-specific negative regulation of cytokine-induced signaling relies on down regulation of the cytokine receptors. Down regulation of the IFNAR1 sub-unit of the Type I interferon (IFN) receptor proceeds via lysosomal receptor proteolysis, which is triggered by ubiquitination that depends on IFNAR1 serine phosphorylation. While IFN-inducible phosphorylation, ubiquitination, and degradation requires the catalytic activity of the Tyk2 Janus kinase, here we found the ligand- and Tyk2-independent pathway that promotes IFNAR1 phosphorylation, ubiquitination, and degradation when IFNAR1 is expressed at high levels. A major cellular kinase activity that is responsible for IFNAR1 phosphorylation in vitro does not depend on either ligand or Tyk2 activity. Inhibition of ligand-independent IFNAR1 degradation suppresses cell proliferation. We discuss the signaling events that might lead to ubiquitination and degradation of IFNAR1 via ligand-dependent and independent pathways and their potential physiologic significance.
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Authors
Jianghuai Liu, Alexander Plotnikov, Anamika Banerjee, K.G. Suresh Kumar, Josiane Ragimbeau, Zrinka Marijanovic, Darren P. Baker, Sandra Pellegrini, Serge Y. Fuchs,