Structural and functional characteristics of ADAMTS-4 and ADAMTS-5: a review

ADAMTS-4 and -5 are aggrecanases that are involved in the development of osteoarthrosis, one of the most common diseases at the moment, due to which a large number of people suffer annually. By some estimates, 9.6% of men and 18% of women over the age of 60 have symptomatic osteoarthrosis. This review discusses the currently known data on the structural features and enzymatic activity of these enzymes. The structures ofADAMTS-4 and -5 are similar, theycontain 7 domain sites: the signal section, the N-terminal prodomain, the catalytic domain, the disintegrin-like domain, the thrombospodin motif, the cysteine-rich domain, and the spacer domain. In addition to all these elements, ADAMTS-5 has an additional thrombospodin motif at the end. ADAMTS-4 and -5 cleaves aggrecan in 5 different binding sites. However, the Glu373-Ala374 site probably plays the most important role in the pathogenesis, since when this bond is broken, the whole aggrecan molecule loses its integrity, which leads to the destruction of cartilage and the development of the disease. In the course of the analysis of the information, the authors have found that the participation of ADAMTS-4 and -5 in the development of osteoarthritis varies greatly depending on the type of organism. The researchers have established that in mice ADAMTS-4 plays the largest role in the destruction of aggrecan, while in humans ADAMTS-5 or both aggrecanases influence the development of osteoarthritis. The revealed differences are not fully described; therefore, this review summarizes the alreadyknown results in this area, which will facilitate further research in this direction.