Interleukin‐6–interleukin‐11 receptor chimeras reveal ionomycin‐induced proteolysis beyond ADAM10

다국어 초록 (Multilingual Abstract)

Interleukin‐6 (IL‐6) and interleukin‐11 (IL‐11) are two important pleiotropic cytokines, both of which signal through a homodimer of the β‐receptor gp130. Specificity is gained through the unique, nonsignaling α‐receptors IL‐6R and IL‐11R. Soluble variants of IL‐6R and IL‐11R also exist. Both membrane‐bound receptors can be cleaved by the metalloprotease ADAM10. Here, we use ten different chimeric receptors consisting of different parts of IL‐6R and IL‐11R and analyze their susceptibility toward cleavage by ADAM10. As expected, all chimeras are substrates of ADAM10. However, we observed that cleavage of chimeric receptors containing the stalk region of the IL‐11R could be blocked by the protease inhibitor GI (selective for ADAM10), but not by the protease inhibitor GW (selective for both ADAM10 and ADAM17), suggesting that another protease besides ADAM10 is involved in cleavage of these chimeras.
Cytokine receptors exist in membrane‐bound and soluble forms. Soluble cytokine receptors are predominantly generated by proteolytic cleavage. Here, we analyze cleavage of the interleukin‐6 and interleukin‐11 receptors (IL‐6R/IL‐11R) by the metalloprotease ADAM10 using different chimeric IL‐6R/IL‐11R proteins. While both IL‐6R and IL‐11R are substrates of ADAM10, our result show unexpectedly that another, so far unidentified protease, can cleave the IL‐11R.