Cleavage Site Localization Differentially Controls Interleukin-6 Receptor Proteolysis by ADAM10 and ADAM17

Abstract

Limited proteolysis of the Interleukin-6 Receptor (IL-6R) leads to the release of the IL-6R ectodomain. Binding of the cytokine IL-6 to the soluble IL-6R (sIL-6R) results in an agonistic IL-6/sIL-6R complex, which activates cells via gp130 irrespective of whether the cells express the IL-6R itself. This signaling pathway has been termed trans-signaling and is thought to mainly account for the pro-inflammatory properties of IL-6. A Disintegrin And Metalloprotease 10 (ADAM10) and ADAM17 are the major proteases that cleave the IL-6R. We have previously shown that deletion of a ten amino acid long stretch within the stalk region including the cleavage site prevents ADAM17-mediated cleavage, whereas the receptor retained its full biological activity. In the present study, we show that deletion of a triple serine (3S) motif (Ser-359 to Ser-361) adjacent to the cleavage site is sufficient to prevent IL-6R cleavage by ADAM17, but not ADAM10. We find that the impaired shedding is caused by the reduced distance between the cleavage site and the plasma membrane. Positioning of the cleavage site in greater distance towards the plasma membrane abrogates ADAM17-mediated shedding and reveals a novel cleavage site of ADAM10. Our findings underline functional differences in IL-6R proteolysis by ADAM10 and ADAM17.

Meprin Metalloproteases Generate Biologically Active Soluble Interleukin-6 Receptor to Induce Trans-Signaling

“…Indeed, recombinant ADAM17 cleaved an IL-6R peptide comprising a part of the stalk region, situated two residues N-terminal of QD between Pro355 and Val35648. This cleavage site was further substantiated by molecular modelling49. Interestingly, meprin α and meprin β were found to exhibit a striking preference for negatively charged amino acids at the P1’ position50, which correlates with the previously observed cleavage site in the IL-6R46.…”

Meprin β cleaves TREM2 and controls its phagocytic activity on macrophages

“…Culture conditions were under a humidified atmosphere (5% of CO 2 ) at 37°C. Generation of HEK293_ADAM10/17 −/− cells was previously described 30 . For transient transfection, cells were seeded in 10 cm cell culture dishes.…”

Effects of interleukin‐6 receptor blockade on allergen‐induced airway responses in mild asthmatics

“…This SNP encodes amino acid 358 (Asp > Ala) of IL-6R, which is located in the extracellular stalk region and coincides precisely with the cleavage site used by ADAM17 to shed mIL-6R. 62,63 Ferreira et al 55 noted that rs2228145:C was associated with substantially lower (~25% decrease per allele) mIL-6R protein expression in primary immune cell types, despite no significant association with RNA levels of the full-length IL6R transcript (based on n = 88). This suggested that rs2228145:C (358Ala) strongly promotes ADAM17-dependent shedding of mIL-6R.…”

“…Second, and perhaps more importantly, rs2228145 is thought to affect mIL‐6R shedding. This SNP encodes amino acid 358 (Asp > Ala) of IL‐6R, which is located in the extracellular stalk region and coincides precisely with the cleavage site used by ADAM17 to shed mIL‐6R . Ferreira et al .…”