title: Jab1, a novel protease-activated receptor-2 (PAR-2)-interacting protein, is involved in PAR-2-induced activation of activator protein-1.
abstract: Protease-activated receptor-2 (PAR-2), a G protein-coupled receptor for trypsin and tryptase, exerts important physiological and pathological functions in multiple systems. However, unlike PAR-1, the PAR-2-mediated intracellular signal transductions are hardly known. Here, using yeast two-hybrid screening with a human brain cDNA library, we identified an interacting partner of human PAR-2, the Jun activation domain-binding protein 1 (Jab1). The interaction was confirmed by glutathione S-transferase pull-down assays in vitro, and by co-immunoprecipitation assays in vivo. Jab1 was also shown to be colocalized with PAR-2 in both transfected HEK293 cells and in normal primary human astrocytes by double immunofluorescence staining. Further experiments demonstrated that multiple intracellular domains of PAR-2 are required for the interaction with Jab1. We then showed that agonist stimulation of PAR-2 disrupted the interaction, which could be prevented by the inhibitor of receptor endocytosis phenylarsine oxide, but not by the lysosomal protease inhibitor ZPAD. Importantly, we found that activation of PAR-2 induced the redistribution of Jab1 from the plasma membrane to the cytosol, but did not influence expression of Jab1. Furthermore, Jab1 mediated PAR-2-induced c-Jun activation, which was followed by increased activation of activator protein-1. Loss-of-function studies, using Jab1 small interfering RNA, demonstrated that Jab1 knockdown blocked PAR-2-induced activator protein-1 activation. Taken together, our data demonstrate that Jab1 is an important effector that mediates a novel signal transduction pathway for PAR-2-dependent gene expression.
authors.affiliation: Institut für Neurobiochemie, Medizinische Fakultät, Otto-von-Guericke-Universität Magdeburg, Leipziger Strasse 44, 39120 Magdeburg, Germany.
authors.forename: Weibo
authors.initials: W
authors.lastname: Luo
authors.forename: Yingfei
authors.initials: Y
authors.lastname: Wang
authors.forename: Theodor
authors.initials: T
authors.lastname: Hanck
authors.forename: Rolf
authors.initials: R
authors.lastname: Stricker
authors.forename: Georg
authors.initials: G
authors.lastname: Reiser
mesh_terms: D000818:Animals; D001152:Arsenicals / Q000737:chemistry; D001253:Astrocytes / Q000378:metabolism; D015153:Blotting, Western; D001921:Brain / Q000378:metabolism; D000075686:COP9 Signalosome Complex; D002460:Cell Line; D002478:Cells, Cultured; D018076:DNA, Complementary / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004705:Endocytosis; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005786:Gene Expression Regulation; D015723:Gene Library; D017930:Genes, Reporter; D005982:Glutathione Transferase / Q000378:metabolism; D006801:Humans; D047468:Immunoprecipitation; D007313:Insecta; D047908:Intracellular Signaling Peptides and Proteins / Q000502:physiology*; D008856:Microscopy, Fluorescence; D008954:Models, Biological; D010447:Peptide Hydrolases / Q000502:physiology*; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D034741:RNA, Small Interfering / Q000378:metabolism; D044464:Receptor, PAR-2 / Q000378:metabolism*; D015398:Signal Transduction; D013997:Time Factors; D018808:Transcription Factor AP-1 / Q000378:metabolism*; D014162:Transfection; D014357:Trypsin / Q000494:pharmacology; D020798:Two-Hybrid System Techniques
chemical_list: D001152:Arsenicals; D018076:DNA, Complementary; D004791:Enzyme Inhibitors; D047908:Intracellular Signaling Peptides and Proteins; D034741:RNA, Small Interfering; D044464:Receptor, PAR-2; D018808:Transcription Factor AP-1; C029341:oxophenylarsine; D005982:Glutathione Transferase; D010447:Peptide Hydrolases; C501488:COPS5 protein, human; D000075686:COP9 Signalosome Complex; D014357:Trypsin