Generation of Soluble Interleukin-11 and Interleukin-6 Receptors: A Crucial Function for Proteases during Inflammation

Figure 2

Proteolytic cleavage of the IL-6R and the IL-11R. The IL-6R is a substrate for ADAM10 (activated by ionomycin or via stimulation of the P2X7R), ADAM17 (activated, e.g., via the phorbol ester PMA), or the NSP cathepsin G (CG). The cleavage sites of ADAM10 and ADAM17 are located close to the plasma membrane. CG appears to cleave further upstream, but the exact cleavage site is not known. In contrast, the IL-11R can be cleaved by ADAM10 and the two NSPs neutrophil elastase (NE) and proteinase 3 (PR3). The exact cleavage sites have not been determined so far.