| Project/Area Number |
06680685
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Cell biology
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| Research Institution | Osaka University |
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Principal Investigator |
OGIHARA Satoshi Osaka University, Faculty of Science, Associate Professor, 理学部, 助教授 (30169221)
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| Project Period (FY) |
1994 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 1995: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1994: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Keywords | Plasma membrane / Exocytosis / Extracellbla matrix / Activ / Psendopoal / エクソサイドシス |
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| Research Abstract |
A very dynamic change in the plasma membrane occurs during cell migration. At the leading edge, the plasma membrane expands while its surface area decreases in the other regions of a cell. Although the expansion has been ascribed to exocytosis of a precursor for the plasma membrane, such precursor has not been identified yet. I investigated the process that couples exocytosis of a 5 mum vesicle (slime vesicle ; sv) and the plasma membrane expansion. As I state here, a highly plausible hypothesis that SV is the plasma membrane precursor is presented.
In a preliminary study that foregoes indicated that Rh-PE (rhodamine phosphatidyl ethanolamine) bind to the plasma membrane precursor. Then I identified the ultrastructure of the precursor using antibodies against rhodamine. SV contained slime, the extracellular matrix of the plasmodium. In the second year of this project, I made it certain that the exocytosis of SV is tightly coupled with protrusion of the plasma membrane at the pseudopod.
… More
SV is the only organelle that invade the hyaline layr at the leading edge. SV migrates toward the cell edge, and then disappears. Then the surface of the plasma membrane in the neighborhood protrudes out. The protruded region is demonstrated to contain actin filaments both optical and electron microscopic level. I raised antibodies against slime and stained cells. The leading edge was densely stained and the patter corresponded with distribution of SV at the electron microscopic level. At a higher magnification, SV was clearly stained.
The above results clearly show that the expansion of the plasma membrane takes place in a quantal way by exocytosis of SV.Summation of such minute protrusion may lead to expansion of the plasma membrane. In other words, there is a possibility that the expanded area of the plasma membrane is totally supplied from SV exocytosis. It seems quite biological that exocytosis of SV which contains the extracellular matrix is coupled with the pseudopod extension. The precursor is quite large enough to serve as a good system that enables to study membrane fusion phenomena and analyze dynamics of plasma membrane expansion in live cells. Less
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