title: Tumor necrosis factor-alpha-converting enzyme (TACE/ADAM-17) mediates the ectodomain cleavage of intercellular adhesion molecule-1 (ICAM-1).
abstract: Ectodomain shedding has emerged as an important regulatory step in the function of transmembrane proteins. Intercellular adhesion molecule-1 (ICAM-1), an adhesion receptor that mediates inflammatory and immune responses, undergoes shedding in the presence of inflammatory mediators and phorbol 12-myristate 13-acetate (PMA). The shedding of ICAM-1 in ICAM-1-transfected 293 cells upon PMA stimulation and in endothelial cells upon tumor necrosis factor-alpha stimulation was blocked by metalloproteinase inhibitors, whereas serine protease inhibitors were ineffective. p-Aminophenylmercuric acetate, a mercuric compound that is known to activate matrix metalloproteinases, up-regulated ICAM-1 shedding. TIMP-3 (but not TIMP-1 or -2) effectively blocked cleavage. This profile suggests the involvement of the ADAM family of proteases in the cleavage of ICAM-1. The introduction of enzymatically active tumor necrosis factor-alpha-converting enzyme (TACE) into ICAM-1-expressing cells up-regulated cleavage. Small interfering RNA directed against TACE blocked ICAM-1 cleavage. ICAM-1 transfected into TACE-/- fibroblasts did not show increased shedding over constitutive levels in the presence of PMA, whereas cleavage did occur in ICAM-1-transfected TACE+/+ cells. These results indicate that ICAM-1 shedding is mediated by TACE. Blocking the shedding of ICAM-1 altered the cell adhesive function, as ICAM-1-mediated cell adhesion was up-regulated in the presence of TACE small interfering RNA and TIMP-3, but not TIMP-1. However, cleavage was found to occur at multiple sites within the stalk domain of ICAM-1, and numerous point mutations within the region did not affect cleavage, indicating that TACE-mediated cleavage of ICAM-1 may not be sequence-specific.
authors.affiliation: Department of Physiology and Biophysics, University of Louisville, Louisville, Kentucky 40292, USA.
authors.forename: Nina L
authors.initials: NL
authors.lastname: Tsakadze
authors.forename: Srinivas D
authors.initials: SD
authors.lastname: Sithu
authors.forename: Utpal
authors.initials: U
authors.lastname: Sen
authors.forename: William R
authors.initials: WR
authors.lastname: English
authors.forename: Gillian
authors.initials: G
authors.lastname: Murphy
authors.forename: Stanley E
authors.initials: SE
authors.lastname: D'Souza
mesh_terms: D051722:ADAM Proteins / Q000502:physiology*; D000072198:ADAM17 Protein; D000818:Animals; D001665:Binding Sites; D015153:Blotting, Western; D002448:Cell Adhesion; D002460:Cell Line; D018076:DNA, Complementary / Q000378:metabolism; D004492:Edetic Acid / Q000737:chemistry; D004533:Egtazic Acid / Q000737:chemistry; D005347:Fibroblasts / Q000378:metabolism; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D018345:Mice, Knockout; D009000:Monocytes / Q000378:metabolism; D009154:Mutation; D017354:Point Mutation; D017434:Protein Structure, Tertiary; D034741:RNA, Small Interfering / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000378:metabolism; D019717:Tissue Inhibitor of Metalloproteinase-3 / Q000378:metabolism; D014162:Transfection; D015854:Up-Regulation
chemical_list: D018076:DNA, Complementary; D034741:RNA, Small Interfering; D019717:Tissue Inhibitor of Metalloproteinase-3; D018799:Intercellular Adhesion Molecule-1; D019716:Tissue Inhibitor of Metalloproteinase-2; D004533:Egtazic Acid; D004492:Edetic Acid; D051722:ADAM Proteins; D000072198:ADAM17 Protein; C000606462:ADAM17 protein, human; C000606463:Adam17 protein, mouse; D013755:Tetradecanoylphorbol Acetate