Gp130 activation is regulated by D2-D3 interdomain connectivity

Antje Schütt, Martin Zacharias, Nico Schneider, Silke Horn, Joachim Grötzinger, Stefan Rose-John, Dirk Schmidt-Arras

Research output: Contribution to journalArticlepeer-review

20 Scopus citations

Abstract

Activation of the IL-6 (interleukin 6) receptor subunit gp130 (glycoprotein 130) has been linked to the formation of complexes with IL-6 and the IL-6 receptor, as well as to gp130 dimerization. However, it has been shown that gp130 is present as a pre-formed dimer, indicating that its activation is not solely dependent on dimerization. Therefore the detailed mechanism of gp130 activation still remains to be deciphered. Recently, deletion mutations of gp130 have been found in inflammatory hepatocellular adenoma. The mutations clustered around one IL- 6-binding epitope of gp130 and resulted in a ligand-independent constitutively active gp130. We therefore hypothesized that conformational changes of this particular IL-6-binding epitope precedes gp130 activation. Using a rational structure-based approach we identified for the first time amino acids critical for gp130 activation. We can show that gp130 D2-D3 interdomain connectivity by hydrophobic residues stabilizes inactive gp130 conformation. Conformational destabilization of the EF loop present in domain D2 and disruption of D2-D3 hydrophobic interactions resulted in ligand-independent gp130 activation. Furthermore we show that the N-terminal amino acid residues of domain D1 participate in the activation of the gp130 deletion mutants. Taken together we present novel insights into the molecular basis of the activation of a cytokine receptor signalling subunit.

Original languageEnglish
Pages (from-to)487-496
Number of pages10
JournalBiochemical Journal
Volume450
Issue number3
DOIs
StatePublished - 15 Mar 2013
Externally publishedYes

Keywords

  • Glycoprotein 130 (gp130)
  • Inflammatory hepatocellular adenoma (IHCA)
  • Interleukin 6 (IL-6)
  • Structure

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