Lack of vacuolar proton ATPase association with the cytoskeleton in osteoclasts of osteosclerotic (oc/oc) mice

We examined the pathogenetic mechanism underlying the lack of bone resorption in osteosclerotic ocloc mice, An immunoelectron microscopic analysis revealed that in the osteoclasts of these mice, no ruffled borders formed, and that vacuolar H+-ATPase (V-ATPase) was present throughout the cytoplasm but not on the apical membranes, The activity of V-ATPase in ocloc mice was similar to that in normal mice, In normal spleen cell-derived osteoclast-like cells (OCLs), immunoreactivity for V-ATPase was detected in association with Triton X-100-insoluble cellular structure, but not in ocloc spleen cell-derived OCLs. Moreover, in renal proximal convoluted tubules of ocloc mice, the basal striation did not form. These results suggest that osteosclerosis in ocloc mice is possibly due to the dissociation of V-ATPase and cytoskeleton in osteoclasts.