The mechanisms and regulation of procathepsin L secretion from osteoclasts in bone resorption.
The secretion mechanisms of cathepsin L from osteoclasts in the process of bone resorption were investigated. The increases in bone pit numbers formed take place by PTH addition in parallel with the increases of cathepsin L and/or L-like proteinase activities in the culture medium of bone cells, and these were suppressed by the addition of calcitonin. The Z-Phe-Arg-MCA hydrolysing activity increased in the medium through the effect of PTH is considered to be a kind of procathepsin L by Western blotting analysis, and was suppressed by calcitonin addition. Furthermore, monensin inhibited not only the PTH-induced pit formation, but also cysteine proteinase activity in osteoclasts. Therefore, the procathepsin L excreted might be transferred from endothelial reticulum via Golgi and/or via lysosomes.
Tagami
K
K
Department of Orthodontics, School of Dentistry, University of Tokushima, Japan.
Kakegawa
H
H
Kamioka
H
H
Sumitani
K
K
Kawata
T
T
Lenarcic
B
B
Turk
V
V
Katunuma
N
N
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D001862:Bone Resorption; D002116:Calcitonin / Q000494:pharmacology; D056668:Cathepsin L; D002403:Cathepsins / Q000378:metabolism*; D004792:Enzyme Precursors / Q000378:metabolism*; D008264:Macrophages / Q000201:enzymology; D008297:Male; D008985:Monensin / Q000494:pharmacology; D010010:Osteoclasts / Q000201:enzymology*; D010281:Parathyroid Hormone / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley
D004792:Enzyme Precursors; D010281:Parathyroid Hormone; D002116:Calcitonin; D008985:Monensin; D002403:Cathepsins; C063905:procathepsin L; D056668:Cathepsin L