| Project/Area Number |
17591945
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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 basic dentistry
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| Research Institution | Health Sciences University of Hokkaido |
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Principal Investigator |
TAKUMA Taishin Health Sciences University of Hokkaido, School of Dentistry, Professor, 歯学部, 教授 (40095336)
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| Co-Investigator(Kenkyū-buntansha) |
ARAKAWA Toshiya Health Sciences University of Hokkaido, School of Dentistry, Assistant Professor, 歯学部, 講師 (40306254)
OKAYAMA Miki Health Sciences University of Hokkaido, School of Dentistry, Assistant Professor, 歯学部, 助教 (30382500)
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| Project Period (FY) |
2005 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2006: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 2005: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Keywords | siRNA / exocytosis / SNARE protein / salivary gland / gene knockdown / SNAP-23 / dominant-negative variant |
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| Research Abstract |
SNAP-23, a non-neuronal isoform of SNAP-25 with 2 tandem SNARE motifs (Qb and Qc), is believed to play a key role as a t-SNARE for both regulated and constitutive exocytosis in most cells that do not express SNAP-25. Here we evaluated the role of SNAP-23 in constitutive exocytotic pathways of HeLa cells. Although the level of SNAP-23 was reduced to less than 10% of the control value by gene silencing with siRNA directed against SNAP-23, exocytosis was normal when transiently expressed SEAP (secreted alkaline phosphatase) was measured as a marker of constitutive secretion. Double knockdown of SNAP-23 and syntaxin-4 also failed to inhibit the secretion. Furthermore, over-expression of δC8-SNAP-23, a dominant-negative SNAP-23, did not abrogate SEAP secretion. When the secretory pathway was visualized by the expression of GFP-tagged human growth hormone (hGH-GFP), however, the accumulation of vesicles containing hGH-GFP was observed in the peripheral plasma membrane of the cells that over-expressed δC8-SNAP-23, although the quantity of hGH-GFP release was not decreased as in the case of SEAP secretion. These results suggest that SNAP-23 is involved in constitutive exocytosis, but is not essential at least for simple exocytosis of secretory proteins.
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