Consistent with previous studies16, the analysis with SignalP and conserved domains databases predicted the presence of (1) an N-terminal 30 amino acid signal sequence for extracellular secretion, (2) a propeptide (31–93) with unclear function, (3) an M9-like domain (94–366), which functions as an activator domain for collagenolysis (but as nuclear transport receptor in eukaryotes)16,36, (4) a peptidase M9 family domain (376–765; referred to as peptidase domain), (5) one polycystic kidney disease (PKD)-like domain (767–850) and (6) one collagen-binding domain (CBD, 853–965), Fig. 1a37–39. The gene discussed is LAP3; the disease is polycystic kidney disease.