title: Catalytic activity of ADAM8, ADAM15, and MDC-L (ADAM28) on synthetic peptide substrates and in ectodomain cleavage of CD23.
abstract: The ADAM family of disintegrin metalloproteases plays important roles in "ectodomain shedding," the process by which biologically active, soluble forms of cytokines, growth factors, and their receptors are released from membrane-bound precursors. Whereas ADAM8, ADAM15, and MDC-L (ADAM28) are expressed in specific cell types and tissues, their in vivo functions and substrates are not known. By screening a library of synthetic peptides as potential substrates, we show that soluble recombinant forms of these enzymes have similar proteolytic substrate specificity, clearly distinct from that of ADAM17 (TNFalpha-converting enzyme). A number of tumor necrosis factor (TNF) family proteins and CD23 were screened as potential substrates for ectodomain cleavage. We found that ADAM8, ADAM15, and MDC-L, but not ADAM17, catalyzed ectodomain shedding of CD23, the low affinity IgE receptor. ADAM8-dependent, soluble CD23 release required proteolytically active ADAM8, and a physical association of ADAM8 was observed with the membrane-bound form of CD23. The ADAM8-dependent release of sCD23 and the endogenous release from B cell lines could be similarly inhibited by a hydroxamic acid, metalloprotease inhibitor compound. We conclude that ADAM8 could contribute to ectodomain shedding of CD23 and may thus be a potential target for therapeutic intervention in allergy and inflammation.
authors.affiliation: Johnson & Johnson Pharmaceutical Research and Development, San Diego, California 92121, USA. afourie@prdus.jnj.com
authors.forename: Anne M
authors.initials: AM
authors.lastname: Fourie
authors.forename: Fawn
authors.initials: F
authors.lastname: Coles
authors.forename: Veronica
authors.initials: V
authors.lastname: Moreno
authors.forename: Lars
authors.initials: L
authors.lastname: Karlsson
mesh_terms: D051722:ADAM Proteins; D000072198:ADAM17 Protein; D015703:Antigens, CD / Q000378:metabolism*; D001402:B-Lymphocytes / Q000166:cytology / Q000378:metabolism; D002460:Cell Line; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D006967:Hypersensitivity / Q000276:immunology / Q000378:metabolism; D007668:Kidney / Q000166:cytology; D008565:Membrane Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D008666:Metalloendopeptidases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D010455:Peptides / Q000378:metabolism; D017434:Protein Structure, Tertiary; D017455:Receptors, IgE / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012995:Solubility; D013379:Substrate Specificity; D014162:Transfection
chemical_list: D015703:Antigens, CD; D004791:Enzyme Inhibitors; D008565:Membrane Proteins; D010455:Peptides; D017455:Receptors, IgE; D051722:ADAM Proteins; C098660:ADAM15 protein, human; C410224:ADAM28 protein, human; C068490:ADAM8 protein, human; D008666:Metalloendopeptidases; D000072198:ADAM17 Protein; C000606462:ADAM17 protein, human