| Project/Area Number |
15590923
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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 |
Neurology
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| Research Institution | National Institute of Neuroscience, NCNP |
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Principal Investigator |
ARAKI Wataru National Institute of Neuroscience, NCNP, Dept.Demyelinating Dis. & Aging, Section Chief, 疾病研究第6部, 室長 (60311429)
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| Co-Investigator(Kenkyū-buntansha) |
KAMETANI Fuyuki Tokyo Institute of Psychiatry, senior research scientist, 主任研究員 (70186013)
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| Project Period (FY) |
2003 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2004: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 2003: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Keywords | Alzheimer's disease / amyloid β-protein / protease |
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| Research Abstract |
β-Secretase, BACE1 is a membrane-bound aspartyl protease critically involved in generation of amyloid β-protein(Aβ), which accumulates in the brain of Alzheimer's disease patients. Inhibition of BACE1 is considered to be a potentially effective therapeutic approach for this disease. We performed proteomic analyses to search for BACE1-interacting proteins using human neuroblastoma SH-SY5Y cells expressing BACE1 with a C-terminal tag. Our method combined glycerol density gradient fractionation, immunoprecipitaion and LC/MS/MS analysis. We identified Nogo-B (reticulon4B ; RTN4B) as a binding protein of BACE1. Co-immunoprecipitaion experiments using transfected HEK293 cells confirmed the physical association between BACE1 and Nogo-B or its homologue, RTN3. Overexpression of Nogo-B or RTN3 reduced secretion of both Aβ40 and Aβ42 by 30-40% in HEK293 cells expressing Swedish mutant amyloid precursor protein(APP). However, these RTN proteins did not influence Aβ secretion in cells expressing APP C-terminal fragment. These data, indicate that Nogo-B and RTN3 can negatively modulate BACE1 cleavage of APP.
The extracellular domain of BACE1 is known to be cleaved partially to generate soluble BACE1. Using immunoprecipitation-Western blot analysis we showed that SH-SY5Y cells overexpressing BACE1 released extracellularly a low but significant amount of BACE1 holoprotein along with soluble BACE1. Our data further indicated that the release of full-length BACE1 was enhanced by inhibition of BACE1 shedding and occurred in parallel with soluble BACE1 release. These data suggest that the extracellular release of full-length BACE1 may be a physiologically significant process.
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