Fig. 5. Formation of the sealing zone in bone resorbing osteoclasts is associated with the dynamic regulations of tubulin acetylation. (A,B) Osteoclasts were differentiated in the presence of RANK-L + M-CSF for 8 days, detached, spread on mineralised matrix (ACC, Apatite Collagen Complex) substrate, which mimics dentin slices, fixed and immunostained with phalloidin-RITC and monoclonal anti-acetylated and polyclonal anti-detyrosinated tubulin antibodies. These two osteoclasts are associated with a resorption pit (*). The osteoclast presented in A is still resorbing, as it exhibits a sealing zone, a large band of F-actin, and has a large number of acetylated but undetectable detyrosinated microtubules. The osteoclast in B is a migrating osteoclast without a sealing zone and showed neither acetylated nor detyrosinated microtubules. Bar, 20 µm.