2005 Fiscal Year Final Research Report Summary
The regulation of functions and expressions of proteins by glycosylphosphatidylinositol-anchor
| Project/Area Number |
16570116
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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 |
Functional biochemistry
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| Research Institution | Osaka University |
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Principal Investigator |
MAEDA Yusuke Osaka University, Research Insitute for Microbial Diseases, Associate Professor, 微生物病研究所, 助教授 (00294124)
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| Co-Investigator(Kenkyū-buntansha) |
KINOSHITA Taroh Osaka University, Research Institute for Microbial Diseases, Professor, 微生物病研究所, 教授 (10153165)
MURAKAMI Yoshiko Osaka University, Research Institute for Microbial Diseases, Research Associate, 微生物病研究所, 助手 (00304048)
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| Project Period (FY) |
2004 – 2005
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| Keywords | GPI-anchor / transport / remodeling / de-acylation / raft |
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| Research Abstract |
(I)Identification of inositol deacylase for GPI (PGAP1).
We identified an inositol deacylase (PGAP1) by expression cloning using deacylase-deficient mutant cells we established and reported that the defect caused the delayed transport of GPI-APs.
(II)Establishment of PGAP1 knockout mice to clarify the biological significance.
We established PGAP1 knockout mice. The majority of PGAP1 null mice was lethal in embryonic stage and showed otocephaly. The other null mice had growth retardation but normal life span. The adult males of null mice were sterile due to defective entrance to oviducts and attachment to egg cells, although the number and motility of sperm was normal.
(III)Lipid remodeling of GPI-anchor and its effects upon the correct sorting and raft association of GPI-APs
We established mutant cell line in which the surface expression of GPI-APs was decreased and identified a new gene, PGAP2, responsible for the defect by expression cloning. The detail analysis of mutants strongly indicated the defect of lipid remodeling of PI portion of GPI-APs during the transport from ER to PM. To understand the defect more in detail, we established double mutant cells whose surface expression of GPI-APs was restored by mutagenizing PGAP2-deficient cells. In double mutant cells, GPI had highly unsaturated lipid chains at sn-2 position of PI, whereas GPI in wild cells exclusively had saturated lipid chain. Moreover such GPI-APs with unsaturated lipid chains associated with rafts much weaker than wild-type cells. These results were first evidences proving that lipid remodeling of GPI takes place in mammalian cells and that lipid remodeling is critical for association of GPI-APs with rafts.
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