The ruffled border and attachment regions of the apposing membrane of resorbing osteoclasts as visualized from the cytoplasmic face of the membrane
The ruffled border and attachment regions of the apposing membrane of resorbing osteoclasts as visualized from the cytoplasmic face of the membrane
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DOI：
10.1093/jmicro/dfl012
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发表时间：
2006-04-01
期刊：
影响因子：
--
通讯作者：
Suzuki, Reiko
中科院分区：
文献类型：
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作者：
Akisaka, Toshitaka;Yoshida, Hisaho;Suzuki, Reiko
本研究的目的是观察破骨细胞质膜的改变以及细胞骨架如何与吸收破骨细胞的附着区和皱褶区相互作用。为了观察膜和相关细胞骨架的表面修饰，我们采用细胞剪切结合快速冷冻和旋转复制的方法来暴露和复制与合成磷灰石作为基质接触的破骨细胞表面膜的细胞质面的广泛区域。与磷灰石相对的膜由三个不同的区域组成：附着区、皱褶边缘和其余区域。在附着区中，高度组织化的肌动蛋白丝网络形成了点状的、富含F-肌动蛋白的粘附位点，即所谓的podosomes和肌动蛋白环。足状体和肌动蛋白环的细胞骨架丝似乎与下面的膜的细胞质表面直接接触。在肌动蛋白环内，单独可识别的足体保存完好，这表明肌动蛋白环可能是由足体融合而来。在褶皱边缘区域剪切后，留下褶皱边缘突起和突起之间的膜区域。这些皱褶状的边缘突起包含细胞骨架网络。这些肌动蛋白网络也似乎是在直接接触的皱褶边缘膜的内侧或通过膜相关颗粒与它接触。在皱褶边缘的基底部，许多网格蛋白包被的斑块或凹坑保存良好。还发现了更深的网格蛋白包被的凹坑和囊泡，这表明受体介导的内吞事件的活性位点。在肌动蛋白环外的细胞周边也观察到网格蛋白片。这种类型的网格蛋白片粘附在磷灰石基底上，但不锚定在肌动蛋白微丝上。因此，我们的研究清楚地显示了在磷灰石颗粒上培养的破骨细胞中，细胞骨架细丝与皱褶边缘、附着区和足体处的下层膜之间的相互作用。
The aim of our present research was to visualize bow the plasma membrane is modified and how the cytoskeleton interacts with the attachment and ruffled border regions of resorbing osteoclasts. In order to view the surface modification of membranes and associated cytoskeleton, we employed the method of cell-shearing combined with quick-freezing and rotary replication to expose and replicate an extensive area of the cytoplasmic face of the surface membrane of osteoclasts in contact with synthetic apatite as a substratum. The membrane apposed to the apatite was composed of three different domains: the attachment zone, ruffled border and the remainder. in the attachment zone, a highly organized actin filament network formed dot-shaped, F-actin rich adhesion sites, so-called podosomes, and the actin ring. The cytoskeletal filament of podosomes and actin ring appeared to be in direct contact with the cytoplasmic surface of the underlying membrane. Within the actin ring, individually recognizable podosomes were well preserved, which indicates that the actin ring was probably derived from the fusion of podosomes. After shearing at the ruffled border region, the ruffled border projections and membrane regions among the projections were left behind. These ruffled border projections contained the cytoskeletal network. These actin networks also appeared to be in direct contact with the inner side of the ruffled border membrane or in contact with it via membrane-associated particles. At the basal portion of the ruffled border, numerous clathrin-coated patches or pits were well preserved. Deeper clathrin-coated pits and vesicles were also found, which indicates an active site for receptor-mediated endocytotic events. Clathrin sheets were also observed in the cell periphery outside of the actin ring. This type of clathrin sheets adhered to the apatite substrate, but was not anchored to the actin microfilaments. Our study thus clearly visualized the interaction between the cytoskeletal filaments and the underlying membrane at the ruffled border, attachment zone and podosome in osteoclasts cultured on apatite pellets.