Figure 1.

Src deletion leads to alterations in adhesion structures and cell migration. (A) Immunofluorescence showing actin (red) and vinculin (green) colocalization (yellow) in Src⁺ and Src⁻ OCLs replated on vitronectin for 1 and 2 h. Micrographs are composites of both channels together. Note the formation of vinculin-rich lamellipodia (blue arrows, Src⁺ 1 and 2 h), which is not seen in Src⁻ OCLs, and the increased redistribution of actin from the central regions of the cell (white arrows) to the peripheral regions of the cell (red arrow, Src⁺ 2 h) in Src⁺ OCLs. These features were not observed in Src⁻ OCLs where actin and vinculin colocalization was observed to significantly increase between 1 and 2 h. (B) Immunofluorescence showing actin (red) and vinculin (green) localization in Src⁺ and Src⁻ authentic osteoclasts cultured on glass coverslips. Note the distinct ring-like assembly of podosomes that stain for both actin and vinculin in Src⁺ osteoclasts (white arrows), and the focal adhesion-like arrangement of vinculin in surrounding contaminating fibroblast-like cells (red arrows, Src⁺ vinculin). In Src⁻ osteoclasts, the localization of actin to the periphery of the osteoclast is not observed (yellow arrow, Src⁻ actin), and staining for vinculin demonstrates a more focal-adhesion–like arrangement (red arrow, Src⁻ vinculin) reminiscent of that seen in the previously described nonosteoclastic cells. (C and D) The lengths of cell migration paths of Src⁻ (C) and c-Cbl⁻ (D) osteoclasts and their littermate wild-type controls were measured at regular intervals as described in Materials and Methods.