Fig. 3

Deconvolution microscopy of GJP endocytosis in Cx43-GFP transfected cells and relation with actin cords. A A GJP (arrow), and an AGJ (large white arrow) are shown. High magnification of the actin distribution reveals the presence of long straight lines (middle panel, red arrows). ImageJ Enhanced local contrast of the same section confirms the organization of actin cables (right panel, red arrows) and shows that the elongated actin cables fuse at a single point far from the plaque (arrowhead). B Superimposition of GFP plaque (green) with actin fibers (red) highlights the specific attachment of actin cables on GJP edges (yellow spots, arrows). C A large GJP (green) seen in face view illustrates the numerous actin cables attached to this structure (arrows). The insets (1–4) point to the contact between single cables and the edge of the GJP (arrows on yellow spots). D In a C-shaped plaque (green), long actin cables (arrows, red) originating from its edges form long cables that approach from a distance far from the plaque. Three cables (arrows) are attached to the curved plaque and junction points are mainly seen at the extremities (yellow dots in the insets). E The U-shaped plaque (green) is prolonged by nearly parallel running actin cables (arrows). During the final steps of GJP endocytosis, from the U-shaped to the unstable form of the GJP, the actin structure changes drastically. F, G The actin cables seem to fuse in a single strand (arrowhead in F) and the remnant cables associated with the curved plaque remain visible; a large actin mass is observed (arrow). The remnant actin cables, detached from the opposite side of the plaque, come close to the future mouth of the forming AGJ and accumulate in a large actin mass (arrows). In G, fine residual actin cords remain attached to the plaque (arrows) on one side and fuse together on the actin mass. H Finally, the final actin mass is located over the mouth of the newly formed AGJ