2007 Fiscal Year Final Research Report Summary
Role of protein L-isoaspartyl(D-aspartyl)methyltransferase in cellular functions
| Project/Area Number |
18590070
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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 |
Biological pharmacy
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| Research Institution | Kitasato University |
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Principal Investigator |
FURUCHI Takemitsu Kitasato University, School of Phamaceutical Sciences, Lecturer (00302167)
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| Project Period (FY) |
2006 – 2007
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| Keywords | Aspartate / Asparagine / PIMT / Isomerization / Racemization / protein repair enzyme |
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| Research Abstract |
Proteins are subject to various types of spontaneous modifications that can disrupt their structures with sometimes adverse affects on biological activity. The formation of L-isoaspartyl (or D-aspartyl) residues, through either the deamidation of asparagine or dehydration of aspartate, is one of the most frequent types of deterioration occurring under physiological conditions. Protein L-isoaspartate/D-aspartate o-methyltransferase (PIMT) is a conserved and ubiquitous enzyme that participates in the repair of various isomerized proteins. PIMT catalyzes the transfer of the methyl group of S-adenosyl-L-methionine onto the α-carboxyl group of an L-isoaspartyl (or the b-carboxyl group of an D-aspartyl) residue, which initiates the conversion of this residue to an L-aspartyl residue. PIMT-deficient mice have been shown to die at a mean age of 42 days from progressive epileptic seizures with grand mal and myoclonus. Although PIMT-deficiency clearly leads to the accumulation of isomerized proteins, it is currently unclear how this causes progressive epilepsy in PIMT-deficient mice. As a first step towards understanding this, we developed a new assay to measure PIMT activity in cell lysates. We also analyzed PIMT promoter activity using Luciferase Reporter Gene Assay System and identified an element essential for transcriptional activation. Additionally, we isolated PIMT knockdown cells from HEK293 cells that were stably transfected with a PIMT small interfering RNA expression vector. PIMT activities were significantly decreased in the PIMT knockdown cells, and analysis of the transfectants revealed that MEK and ERK were hyperactivated after cell stimulation with epidermal growth factor (EGF). These results indicate that the ability to repair L-isoaspartyl-(or D-aspartyl-)containing proteins is important for the maintenance of normal MEK-ERK signaling.
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[Journal Article] Cloning and functional characterization of Arabidopsis thaliana D-amino acid aminotransferase-D-aspartate behavior during germination2008
Author(s)
Funakoshi, M., Sekine, M., Katane, M., Furuchi, T., Yohda, M., Yoshikawa, T., Homma, H
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Journal Title
FEBS J 275(6)
Pages: 1188-1200
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Suppression of protein l-isoaspartyl(d-aspartyl)methyltransferase results in hyperactivation of EGF-stimulated MEK-ERK signaling in cultured mammalian cells2008
Author(s)
Kosugi, S., Furuchi, T., Katane, M., Sekine, M., Shirasawa, T., Homma, H
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Journal Title
Biochem Biophys Res Commun 371(1)
Pages: 22-27
Description
「研究成果報告書概要(欧文)」より
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