Figure 5
V-ATPase localisation in human OCs exhibiting APs, SZs and PDs.
F-actin is displayed in green, V-ATPase in magenta and reflection from bone in cyan. (a–d) a 2.5 μm maximum projection of OCs above RPs with ongoing active resorption show an accumulation of V-ATPase at the bone interface. Actively resorbing cells are devoid of V-ATPase filled vacuoles, but have smaller puncta representing acidified endosomes and lysosomes. A 2.5 μm maximum projection (e–h) of an OC displaying a SZ structure and a medium intensity of V-ATPase in the middle of the SZ. Further away from the bone interface are seen vacuoles filled with V-ATPase, along with endosomes and lysosomes. In a 5 μm maximum projection of OCs grown on glass (i–k) no accumulation V-ATPase was observed at the glass interface, in abundant endosomes and lysosomes and V-ATPase filled vacuoles were a typically seen stored inside the cell (bottom center). Boxes in (b,f,j) outline the field of view in the merge images (d,h,k). Arrowheads point to V-ATPase stained vacuoles. We selected the representative images from 18 V-ATPase stained SZs and N > 20 APs and PDs. Scale bar in (a,e,i)is 10 μm and in (d,h,l)5 μm.
