title: Enhancing Interleukin-6 and Interleukin-11 receptor cleavage.
abstract: Proteolytic cleavage of the membrane-bound Interleukin-6 receptor (IL-6R) by the metalloprotease ADAM17 releases an agonistic soluble form of the IL-6R (sIL-6R), which is responsible for the pro-inflammatory trans-signaling branch of the cytokine's activities. This proteolytic step, which is also called ectodomain shedding, is critically regulated by the cleavage site within the IL-6R stalk, because mutations or small deletions within this region are known to render the IL-6R irresponsive towards proteolysis. In the present study, we employed cleavage site profiling data of ADAM17 to generate an IL-6R with increased cleavage susceptibility. Using site-directed mutagenesis, we showed that the non-prime sites P3 and P2 and the prime site P1' were critical for this increase in proteolysis, whereas other positions within the cleavage site were of minor importance. Insertion of this optimized cleavage site into the stalk of the Interleukin-11 receptor (IL-11R) was not sufficient to enable ADAM17-mediated proteolysis, but transfer of different parts of the IL-6R stalk enabled shedding by ADAM17. These findings shed light on the cleavage site specificities of ADAM17 using a native substrate and reveal further differences in the proteolysis of IL-6R and IL-11R.
authors.affiliation: Institute of Biochemistry, Kiel University, 24118 Kiel, Germany.
authors.forename: Juliane
authors.initials: J
authors.lastname: Lokau
authors.affiliation: Institute of Biochemistry, Kiel University, 24118 Kiel, Germany.
authors.forename: Marieke
authors.initials: M
authors.lastname: Wandel
authors.affiliation: Institute of Biochemistry, Kiel University, 24118 Kiel, Germany. Electronic address: cgarbers@biochem.uni-kiel.de.
authors.forename: Christoph
authors.initials: C
authors.lastname: Garbers
mesh_terms: D000072198:ADAM17 Protein / Q000737:chemistry / Q000235:genetics; D001665:Binding Sites; D015153:Blotting, Western; D020134:Catalytic Domain / Q000235:genetics; D014644:Genetic Variation; D057809:HEK293 Cells; D006801:Humans; D015850:Interleukin-6 / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D059748:Proteolysis; D053702:Receptors, Interleukin-11 / Q000235:genetics / Q000378:metabolism*; D019947:Receptors, Interleukin-6 / Q000235:genetics / Q000378:metabolism*
chemical_list: C508600:IL6 protein, human; D015850:Interleukin-6; D053702:Receptors, Interleukin-11; D019947:Receptors, Interleukin-6; D000072198:ADAM17 Protein
keywords: ADAM17; Cleavage site; Interleukins; Proteolysis; Trans-signaling