Cathepsins in the osteoclast

摘要: The mechanism by which bone collagen and other organic components are degraded the osteoclast during osteoclastic resorption was unclear until 1980s. Studies conducted since early 1990s have identified lysosomal proteases, mainly cathepsins that active at low pH, involved in resorption. Several cathepsins, such as C, D, B, E, G L, were initially demonstrated to take part degradation of matrix osteoclasts. Cathepsin K, has high proteolytic activity localizes primarily osteoclasts, discovered 1995. This first tissue-specific cathepsin associated with pycnodysostosis, a genetic disorder observable an osteopetrotic phenotype K-deficient mice. Cystatin endogenous inhibitor cysteine regulates K. However, detailed morphological observations suggest is not only but also metalloproteinases or cathepsins. possesses unique endocytotic/exocytotic structure each specifically localized osteoclast, implies contributes cooperatively process Further studies may clarify regulation activities roles remodelling.