title: Aggrecanase-1 (ADAMTS-4) interacts with alpha1-antitrypsin.
abstract: In degradative articular diseases such as rheumatoid arthritis and osteoarthritis, loss of the extracellular matrix occurs, resulting in the destruction of joint cartilage. Proteolysis of aggrecan is one of the early events that leads to breakdown of the extracellular matrix. Aggrecanase-1 (ADAMTS--4) is considered to play a pivotal role in the abrasion of cartilage aggrecan in rheumatoid arthritis and osteoarthritis. To identify an endogenous inhibitor of aggrecanase-1, we performed a yeast two-hybrid screen using the catalytic domain of human aggrecanase-1 as a bait and transformed an EGY 48 yeast strain carrying the bait plasmid with a human liver cDNA library plasmid. This screen identified alpha1-antitrypsin, a member of the family of plasma serine proteinase inhibitors, as a prey. Recombinant aggrecanase-1 and alpha1-antitrypsin were expressed in mammalian cells and used in co-immunoprecipitation experiments, which showed that full-length aggrecanase-1 and alpha1-antitrypsin are also associated in vivo. However, aggrecanase-1 did not interfere with the inhibitory activity of alpha1-antitrypsin against elastase, and alpha1-antitrypsin had no effect on the proteolytic activity of aggrecanase-1. Taken together, these data suggest that aggrecanase-1 and alpha1-antitrypsin bind in vivo, although the physiological significance of the interaction between aggrecanase-1 and alpha1-antitrypsin remains unclear.
authors.affiliation: Department of Biochemistry, Kinki University School of Medicine, Osaka-Sayama, Osaka 589-8511, Japan. kojiy@med.kindai.ac.jp
authors.forename: Koji
authors.initials: K
authors.lastname: Yoshida
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Suzuki
authors.forename: Akio
authors.initials: A
authors.lastname: Saito
authors.forename: Kanji
authors.initials: K
authors.lastname: Fukuda
authors.forename: Chiaki
authors.initials: C
authors.lastname: Hamanishi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Munakata
mesh_terms: D051722:ADAM Proteins; D000071121:ADAMTS4 Protein; D000818:Animals; D001665:Binding Sites; D019556:COS Cells; D002522:Chlorocebus aethiops; D004789:Enzyme Activation; D006801:Humans; D008666:Metalloendopeptidases / Q000737:chemistry* / Q000378:metabolism*; D011348:Procollagen N-Endopeptidase; D011485:Protein Binding; D011994:Recombinant Proteins / Q000378:metabolism; D020798:Two-Hybrid System Techniques; D000515:alpha 1-Antitrypsin / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D011994:Recombinant Proteins; D000515:alpha 1-Antitrypsin; D051722:ADAM Proteins; D008666:Metalloendopeptidases; D011348:Procollagen N-Endopeptidase; D000071121:ADAMTS4 Protein; C000603918:ADAMTS4 protein, human