ADAM17 cytoplasmic domain modulates Thioredoxin-1

We have previously shown that Thioredoxin-1 (Trx-1) binds to the cytoplasmic domain of ADAM17 (ADAM17cyto), A Disintegrin And Metalloprotease 17, and that the destabilization in their interface of interaction favors the Trx-1 dimeric and inactive state. These studies opened the question of whether ADAM17 plays a role in the modulation of Trx-1 conformation and activity. Here, we demonstrate that site-directed mutagenesis in ADAM17 (ADAM17cytoF730A) also disrupts the interacting interface with Trx-1, resulting in a decrease of Trx-1 reductive capacity and activity. One of the mechanisms that explain this effect might be that ADAM17cyto favors Trx-1 monomerization state - the active state - by forming a disulfide bond between Cys824 at the C-terminal of ADAM17cyto with the Cys73 of Trx-1, which is involved in the dimerization site. Both the free Trx-1 Cys73 peptide and the disulfide bond Trx-1 Cys73-ADAM17 Cys824 peptide were measured by SRM.