FIGURE 6.

Furin-processed ADAMTS10 can cleave fibrillin-1. ADAMTS10 proteolytic activity toward fibrillin-1 was determined in HEK293F cells stably transfected with wild-type ADAMTS10 (WT) or the indicated mutants. The transfected cells (+cells) or their conditioned medium (−cells) as indicated was incubated with peptide rF6 (asterisk). ADAMTS10 (WT) cleaves rF6 to generate a 60-kDa peptide (top panel, double asterisk), but this cleavage is much more robust with ADAMTS10-RRKR. When rF6 digests were done using ADAMTS10-conditioned cell-free medium, cleavage by wild-type ADAMTS10 was undetectable. Mutation of the ADAMTS10 catalytic Glu³⁹³ residue (to Ala) in each construct abrogated cleavage and is indicative of specific cleavage by ADAMTS10 in this experiment. The lower panel shows the ADAMTS10 molecular species detected by Western blotting with anti-myc. IB, immunoblot; Z, zymogen; M, mature form.