Serum calcium-decreasing factor, caldecrin, inhibits osteoclast differentiation by suppression of NFATc1 activity.

Caldecrin/chymotrypsin C is a novel secretory-type serine protease that was originally isolated as a serum calcium-decreasing factor from the pancreas. Previously, we reported that caldecrin suppressed the bone-resorbing activity of rabbit mature osteoclasts (Tomomura, A., Yamada, H.