Cysteine-proteinase localization in osteoclasts: an immunocytochemical study.
Cysteine-proteinases such as cathepsin B and G were localized in rat osteoclasts, by an indirect protein A-immunogold labeling technique, on post-embedded ultrathin sections. In osteoclasts, specific immunogold labeling of both anti-cathepsin B and G was localized in Golgi vesicles, lysosomes, pale vacuoles of various sizes, and the extracellular canals of ruffled borders; no immunoreactivity was seen in the cytoplasmic matrix, mitochondria, cisterns of the rough endoplasmic reticulum, or nuclei. The presence of immunolabeling of cathepsins in osteoclasts and in the subosteoclastic compartment suggests that these enzymes are involved in the extracellular degradation of collagen and other non-collagenous bone matrix proteins.
Sasaki
T
T
Second Department of Oral Anatomy, School of Dentistry, Showa University, Tokyo, Japan.
Ueno-Matsuda
E
E
D000818:Animals; D001857:Bone Matrix / Q000201:enzymology; D001862:Bone Resorption / Q000378:metabolism; D002401:Cathepsin B / Q000378:metabolism*; D056649:Cathepsin G; D002403:Cathepsins / Q000378:metabolism*; D007150:Immunohistochemistry; D008247:Lysosomes / Q000201:enzymology; D010010:Osteoclasts / Q000201:enzymology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012697:Serine Endopeptidases; D014617:Vacuoles / Q000201:enzymology
D002403:Cathepsins; D012697:Serine Endopeptidases; D056649:Cathepsin G; C534097:Ctsg protein, rat; D002401:Cathepsin B