Fig. 4. Localization of total _vß₃ in resorbing OC. A resorbing OC is schematically represented in A. It appears as a polarized cell, attached to the bone through the sealing zone (SZ), that forms a specific membrane domain, the ruffled border (RB) involved in the dissolution of the bone matrix. Primary human OCs were plated onto bone slices in the presence of 10% FBS, and stained by double immunofluorescence with the anti-ß₃ mAb AP3 followed by cyanine-3-conjugated rabbit anti-mouse IgG (B,D,F) and by fluorescein-tagged phalloidin (C,E,G). Microscopic images show the three different axial sections indicated in A: (B-C) at the level of the SZ, where _vß₃ (B) appears as a circular line at the cell periphery that perfectly colocalizes with the actin ring (C); (D-E) in RB, _vß₃ and the actin show a punctuate distribution; (F-G) an optical yz-plane confirms the distribution of the integrin and of the actin in the SZ and in the RB. Bar, 5 µm.