1995 Fiscal Year Final Research Report Summary
MOLECULAR ANALYSIS OF STRUCTURE-FUNCTION RELATIONSHIP OF GLUCOSE TRANSPORTER AND INSULIN ACTION
| Project/Area Number |
06454333
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
内分泌・代謝学
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| Research Institution | YAMAGUCHI UNIVERSITY |
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Principal Investigator |
OKA Yoshitomo YAMAGUCHI UNIVERSITY SCHOOL OF MEDICINE PROFESSOR, 医学部, 教授 (70175256)
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| Co-Investigator(Kenkyū-buntansha) |
ZAITU Yuzuru YAMAGUCHI UNIVERSITY SCHOOL OF MEDICINE INSTRUCTOR, 医学部・附属病院, 医員
YOSHIDA Tuyoshi YAMAGUCHI UNIVERSITY SCHOOL OF MEDICINE INSTRUCTOR, 医学部・附属病院, 医員
TANIZAWA Yukio YAMAGUCHI UNIVERSITY SCHOOL OF MEDICINE ASSISTSNT PROFESSOR, 医学部・附属病院, 助手 (00217142)
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| Project Period (FY) |
1994 – 1995
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| Keywords | glucose transporter / glucose transport / molecular engineering / fructose transport |
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| Research Abstract |
The biological and biochemical properties of glucose transpoter isoforms have been investigated. The rat GLUT5 cDNA was transfected into Chinese hamster ovary cells with an expression vector. GLUT5 was exclusively targeted to the plasma membrane and exhibited a transport activity, not for glucose, but for fructose with much higher affinity than GLUT2, the other glucose transporter with fructose transport activity. Interestingly, GLUT5 was not photolabeled with cytochalasin B,while a similar amount of GLUT1 was adequately photolabeled under the same experimental conditions. In addition, to elucidate the domains responsible for transport of glucose/fructose in GLUT1 and/or GLUT5, several chimeric GLUT1/GLUT5 proteins were expressed and their glucose transport and/or fructose transport activities were examined. The intracellular middle loop as well as the region encompassing from the 7th through the 12th membrane spanning domain were observed to have a crucial role in glucose transport of GLUT1, while replacement of the N-terminal half or the intracellular C-terminal region with the corresponding region of GLUT5 did not induce a marked effect on glucose transport activity. In contrast, both the N-terminal half from the N-terminus through the 6th membrane spanning domain and the intracellular C-terminal region were mandatory for fructose transport of GLUT5. Thus, GLUT5 is a transporter exclusively for fructose and the structure required for fructose transport is more stringent than that for glucose transport in hexose transporter proteins.
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