Figure 8

Regulation of CatK secretion by oxLDL. (A) The process of osteoclastogenesis without oxLDL. LAMP2 residing vesicles (v-ATPase and CatK) fuse readily to the ruffled border leading to an active protonation of the resorption lacunae and CatK secretion. Cytoskeletal rearrangement leads to actin rings which actively seals the resorption site from the environment. (B) The process of osteoclastogenesis when oxLDL is present. oxLDL binds to the SR-A in osteoclast precursor cells inhibiting the process of autophagy. This leads to an accumulation of LAMP2 residing vesicles (v-ATPase and CatK) in the cell and hence, an impaired bone resorption. Also the cytoskeletal rearrangement is impaired leading to actin rings that cannot shield the resorption site from the environment.