Stage-specific activation of MIG-17/ADAMTS controls cell migration in Caenorhabditis elegans.

The activation of ADAMTS (a disintegrin and metalloprotease with thrombospondin motifs) family proteases depends on removal of the prodomain. Although several studies suggest that ADAMTS activities play roles in development, homeostasis and disease, it remains unclear when and where the enzymes are activated in vivo. MIG-17, a Caenorhabditis elegans glycoprotein belonging to the ADAMTS family, is secreted from the body wall muscle cells and localizes to the gonadal basement membrane to control the migration of gonadal distal tip cells. Here, we developed a monoclonal antibody that recognizes the N-terminal neo-epitope of the activated MIG-17. In western blotting, the antibody specifically detected the activated form, the signal for which dramatically increased during the third and fourth larval stages, when MIG-17 is required to direct distal tip cell migration. In in situ staining, the monoclonal antibody recognized the activated form in the basement membrane, whereas it failed to detect a processing-resistant mutant form localized to the basement membrane. MIG-17 was activated in the basement membranes of the muscle, intestine and gonad in the third larval stage, and downregulated in nongonadal basement membranes in young adults and in gonadal basement membranes in older adults. Thus, the activation of MIG-17 is regulated in a spatiotemporal manner during C. elegans development. This is the first report demonstrating the regulated activation of an ADAMTS protein in vivo. Our results suggest that monoclonal antibodies against neo-epitopes have potential as powerful tools for detecting activation of ADAMTSs during development and in disease pathogenesis.