1997 Fiscal Year Final Research Report Summary
Morphological studies on the transfer machinery molecules in the blood-tissue barriers.
| Project/Area Number |
07457002
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
General anatomy (including Histology/Embryology)
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| Research Institution | GUNMA UNIVERSITY |
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Principal Investigator |
TAKATA Kuniaki GUNMA UNIVERSITY Institute for Molecular and cellular Regulation, Department of Cell Biology, Professor, 生体調節研究所, 教授 (20129290)
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| Project Period (FY) |
1995 – 1997
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| Keywords | blood-tissue barriers / transport / epithelium / sugar transporter / GLUT1 / GLUT5 / gap junction / connexin |
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| Research Abstract |
Transfer machimery in the blood-tissue barriers were studied using isoform-specific antibodies. In barrieres made of a single epithelial or endothelial cell layrs, GLUT1 sugar transporter was localized at plasma membranes of both apical and basolateral domains of them. In barriers composed of double-epithelial cell layrs such as the epithelium of the ciliary body (blood-aqueous barriers) and the rat trophoblasts (placental barrier), GLUT1 was abundant at plasma membranes located at each side of the barrier layr. Two adjacent cell layrs were connected by numerous gap junctions of connexin 43 or connexin 26. Considering the location and abundance of transporters and connexin isoforms, I proposed the glucose transfer machinery in these double-cell barriers as follows : entry of glucose into the first barrier cell layr via GLUT1 ; transfer to the second barrier layr via connexin 43 (or 26) ; exit from the second barrier cell layr via GLUT1. These results suggest that transfer of substances with low-molecular weight is mediated with the combination of specific transporters (or channels) connexin isoforms and specific transporters (or channels) aligned in series. Molecular mechanism for specific localization of sugar transporter molecules was assessed by expressing GLUT1 and GLUT5 sugar transporter genes and their chimeras in cultured epithelial cells. Immunocytochemical analysis revealed that cytoplasmic loop domain plays an important role in determining their localization on the plasma membrane in polarized epithelial cells.
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