Mutations in the interglobular domain of aggrecan alter matrix metalloproteinase and aggrecanase cleavage patterns: Evidence that matrix metalloproteinase cleavage interferes with aggrecanase activity

Abstract

We have expressed G1-G2 mutants with amino acid changes at the DIPEN341↓342FFGVG and ITEGE373↓374-ARGSV cleavage sites, in order to investigate the relationship between matrix metalloproteinase (MMP) and aggrecanase activities in the interglobular domain (IGD) of aggrecan. The mutation DIPEN341 to DIGSA341 partially blocked cleavage by MMP-13 and MMP-8 at the MMP site, while the mutation 342FFGVG to 342GTRVG completely blocked cleavage at this site by MMP-1, -2, -3, -7, -8, -9, -13, -14. Each of the MMP cleavage site mutants, including a four-amino acid deletion mutant lacking residues ENFF343, were efficiently cleaved by aggrecanase, suggesting that the primary sequence at the MMP site had ..