Osteoclasts seeded on either glass coverslips or apatite pellets have at least two morphologically distinct substrate adhesion sites: actin-based adhesion structures including podosome belts and sealing zones, and adjacent clathrin sheets. Clathrin-coated structures are exclusively localized at the podosome belts and sealing zone, in both of which the plasma membrane forms a tight attachment to the substrate surface. When cultured on apatite osteoclasts can degrade the apatite leading to the formation of resorption lacunae. The sealing zone divides the ventral membrane into different domains, outside and inside of the sealing zones. The former facing the smooth-surfaced intact apatite contains relatively solitary or networks of larger flat clathrin structures; and the latter, facing the rough-surfaced degraded apatite in the resorption lacunae contain clathrin in various shapes and sizes. Clathrin assemblies on the membrane domain facing not only a resorption lacuna, or trails but also intact apatite indeed were observed to be heterogeneous in size and intensity, suggesting that they appeared to follow variations in the surface topography of the apatite surface. These results provide a detailed insight into the flat clathrin sheets that have been suggested to be the sites of adhesion and mechanosensing in co-operation with podosomes.

接种在玻璃盖玻片或磷灰石小球上的破骨细胞具有至少两个形态上不同的底物粘附位点：基于肌动蛋白的粘附结构，包括足小体带和密封区，以及相邻的网格蛋白片。包被网格蛋白的结构仅位于足小体带和密封区域，质膜在这两个区域均形成与底物表面的紧密附着。当在磷灰石上培养时，破骨细胞会降解磷灰石，从而导致吸收性腔隙的形成。密封区域将腹膜分为密封区域外部和内部的不同区域。面对光滑的完整磷灰石的前者包含较大的扁平网格蛋白结构的相对孤立或网状结构；而后者，在吸收腔中面对粗糙降解磷灰石的表面含有各种形状和大小的网格蛋白。实际上，观察到膜区域上的网格蛋白组装体不仅面对吸收凹腔或痕迹，而且还面对完整的磷灰石，其大小和强度实际上是异质的，这表明它们似乎跟随着磷灰石表面的表面形貌变化。这些结果提供了对扁平网格蛋白片的详细了解，扁平网格蛋白片被认为是与足囊合作的粘附和机械传感部位。这表明它们似乎遵循磷灰石表面的表面形貌变化。这些结果提供了对扁平网格蛋白片的详细了解，扁平网格蛋白片被认为是与足囊合作的粘附和机械传感部位。这表明它们似乎遵循磷灰石表面的表面形貌变化。这些结果提供了对扁平网格蛋白片的详细了解，扁平网格蛋白片被认为是与足囊合作的粘附和机械传感部位。