title: Variations in aggrecan structure modulate its susceptibility to aggrecanases.
abstract: Proteoglycan aggregates and purified aggrecan from adult and fetal bovine cartilage and adult and neonatal human cartilage were subjected to in vitro degradation by recombinant aggrecanase-1 and aggrecanase-2. The ability of the aggrecanases to cleave within the aggrecan IGD (interglobular domain) and CS2 domain (chondroitin sulphate-rich domain 2) was monitored by SDS/PAGE and immunoblotting. Aggrecanase-2 showed a similar ability to cleave within the IGD of adult and immature aggrecan, whereas aggrecanase-1 was less efficient in cleavage in the IGD of immature aggrecan, for both the bovine and the human substrates. Both aggrecanases showed a similar ability to cleave within the CS2 domain of bovine aggrecan irrespective of age, but showed a much lower ability to cleave within the CS2 domain of human aggrecan. Equivalent results were obtained whether aggrecan was present in isolation or as part of proteoglycan aggregates. When proteoglycan aggregates were used, neither aggrecanase was able to cleave link protein. Thus, for aggrecan cleavage by aggrecanases, variations in cleavage efficiency exist with respect to the species and age of the animal from which the aggrecan is derived and the type of aggrecanase being used.
authors.affiliation: Shriners Hospital for Children, 1529 Cedar Avenue, Montreal, Quebec, Canada H3G 1A6. proughley@shriners.mcgill.ca
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Roughley
authors.forename: James
authors.initials: J
authors.lastname: Barnett
authors.forename: Fengrong
authors.initials: F
authors.lastname: Zuo
authors.forename: John S
authors.initials: JS
authors.lastname: Mort
mesh_terms: D051722:ADAM Proteins; D000071121:ADAMTS4 Protein; D000071116:ADAMTS5 Protein; D000368:Aged; D053674:Aggrecans; D000818:Animals; D002356:Cartilage / Q000737:chemistry / Q000196:embryology / Q000254:growth & development; D002417:Cattle; D016326:Extracellular Matrix Proteins; D006801:Humans; D007231:Infant, Newborn; D037181:Lectins, C-Type; D008666:Metalloendopeptidases / Q000378:metabolism*; D011348:Procollagen N-Endopeptidase; D017434:Protein Structure, Tertiary; D011509:Proteoglycans / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D053674:Aggrecans; D016326:Extracellular Matrix Proteins; D037181:Lectins, C-Type; D011509:Proteoglycans; D051722:ADAM Proteins; D000071116:ADAMTS5 Protein; C121532:ADAMTS5 protein, human; D008666:Metalloendopeptidases; D011348:Procollagen N-Endopeptidase; D000071121:ADAMTS4 Protein