title: ADAM17-mediated shedding of FcγRIIIA on human NK cells: identification of the cleavage site and relationship with activation.
abstract: FcγRIIIA/CD16A, the low-affinity receptor for the IgG Fc portion expressed on human CD56(dim) NK cells and involved in Ab-dependent cell cytotoxicity, is shed upon NK cell activation. We found that recombinant a disintegrin and metalloprotease (ADAM) 17 cleaved the ectodomain of FcγRIIIA/CD16A and a peptide for which the sequence encompasses aa 191-201 of the FcγRIIIA/CD16A stalk region but not ADAM10. MALDI-TOF analysis revealed that the peptide was cleaved between Ala(195) and Val(196) (i.e., 1 aa upstream of the expected position). This location of the cleavage site was confirmed by the finding that ADAM17 failed to cleave a peptide in which Ala and Val were reversed. ADAM17 was found to be expressed on NK cells, and stimulation with PMA or N-ethyl-maleimide resulted in the shedding of FcγRIIIA/CD16A and CD62L, a specific substrate of ADAM17. Selective inhibition of ADAM17 prevented the shedding of both molecules. Moreover, the shedding of FcγRIIIA/CD16A was strongly correlated with degranulation when a wide range of CD56(dim) NK cell activating receptors were stimulated, whereas both ADAM17-dependent shedding and internalization were involved in FcγRIIIA/CD16A downmodulation when the latter was engaged. Finally, the shedding of FcγRIIIA/CD16A was restricted to activated cells, suggesting that ADAM17 acts mainly, if not exclusively, in cis. Taken together, our results demonstrated for the first time, to our knowledge, at the molecular level that ADAM17 cleaves the stalk region of FcγRIIIA/CD16A and identified its cleavage site. The shedding of FcγRIIIA/CD16A was at least partially ADAM17 dependent, and it may be considered as a marker of FcγRIIIA/CD16A-independent NK cell activation highly correlated with degranulation.
authors: Centre National de la Recherche Scientifique Unité Mixte de Recherche 7292, Génétique, Immunothérapie, Chimie et Cancer, Université François-Rabelais de Tours, 37032 Tours Cedex, France;
authors: Laurie
authors: L
authors: Lajoie
authors: Nicolas
authors: N
authors: Congy-Jolivet
authors: Armelle
authors: A
authors: Bolzec
authors: Valérie
authors: V
authors: Gouilleux-Gruart
authors: Elodie
authors: E
authors: Sicard
authors: Hsueh Cheng
authors: HC
authors: Sung
authors: Frank
authors: F
authors: Peiretti
authors: Thierry
authors: T
authors: Moreau
authors: Henri
authors: H
authors: Vié
authors: Béatrice
authors: B
authors: Clémenceau
authors: Gilles
authors: G
authors: Thibault
mesh_terms: D051722:ADAM Proteins / Q000378:metabolism*; D000072198:ADAM17 Protein; D001665:Binding Sites; D002478:Cells, Cultured; D006801:Humans; D007694:Killer Cells, Natural / Q000378:metabolism*; D010455:Peptides / Q000378:metabolism; D017452:Receptors, IgG / Q000378:metabolism*
chemical_list: C496124:FCGR3A protein, human; D010455:Peptides; D017452:Receptors, IgG; D051722:ADAM Proteins; D000072198:ADAM17 Protein; C000606462:ADAM17 protein, human