2005 Fiscal Year Final Research Report Summary
Podosome structures as a focal adhesion appeared in osteoclasts in culture
| Project/Area Number |
16591848
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Morphological basic dentistry
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| Research Institution | Asahi University |
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Principal Investigator |
AKISAKA Toshitaka Asahi University, Department of Anatomy, Professor, 歯学部, 教授 (70116523)
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| Co-Investigator(Kenkyū-buntansha) |
YOSHIDA Hisaho Asahi University, Department of Anatomy, Assistant professor, 歯学部, 助手 (80102119)
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| Project Period (FY) |
2004 – 2005
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| Keywords | osteoclast / focal adhesion / cell shearing / podosome / actin ring / quick freezing / stereopair / 3-D visualization |
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| Research Abstract |
Osteoclasts are large, multinucleated cells specialized for the degradation of mineralized matrix. In the harmony with osteoblastic bone formation, osteoclastic bone resorption is essential for the dynamic equilibrium of bone homeostasis. The aim of our present research was to visualize how 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 3 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.
Cell shearing combined with quick-freezing microscopy was used as we considered that this method would give more detailed information on the cytoplasmic surface of membrane in the attachment zone and ruffled border region.
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