title: TACE/ADAM-17 enzymatic activity is increased in response to cellular stimulation.
abstract: Tumor necrosis factor-alpha converting enzyme (TACE/ADAM-17) is a metalloprotease disintegrin that cleaves a variety of membrane proteins, releasing ("shedding") their extracellular domains from cells. Most TACE-mediated shedding events occur at low basal rates that are enhanced by treatment of cells with a variety of stimuli. To study the mechanism of induced shedding, we developed a peptide-cleavage assay that measures the cellular TACE activity. In unstimulated cells, cleavage of a TNFalpha processing-site peptide was mediated mainly by enzymes other than TACE. However, stimulation of cells with phorbol-12-myristate-13-acetate (PMA) increased peptide cleavage in a TACE-dependent manner. PMA treatment did not increase the amount of TACE on the cell surface. Moreover, the cytoplasmic domain of TACE was not required for the induced activity. Based on these observations, induction of TACE-mediated shedding events occurs at least in part via an increase in the enzymatic activity of cellular TACE, independent of its cytoplasmic domain.
authors.affiliation: Department of Cell Biology, Amgen Inc., 51 University St., Seattle, WA 98101, USA. doedensj@amgen.com
authors.forename: John R
authors.initials: JR
authors.lastname: Doedens
authors.forename: Rajeev M
authors.initials: RM
authors.lastname: Mahimkar
authors.forename: Roy A
authors.initials: RA
authors.lastname: Black
mesh_terms: D051722:ADAM Proteins; D000072198:ADAM17 Protein; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology; D003593:Cytoplasm / Q000187:drug effects / Q000201:enzymology; D008666:Metalloendopeptidases / Q000737:chemistry / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D009842:Oligopeptides / Q000737:chemistry / Q000378:metabolism; D017434:Protein Structure, Tertiary; D013379:Substrate Specificity; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014161:Transduction, Genetic
chemical_list: D009842:Oligopeptides; D051722:ADAM Proteins; D008666:Metalloendopeptidases; D000072198:ADAM17 Protein; C000606463:Adam17 protein, mouse; D013755:Tetradecanoylphorbol Acetate