Identification of glycosylation site involving into substrate preference of gamma-secretase

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K07044
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Nerve anatomy/Neuropathology
• Research Institution: Doshisha University
• Principal Investigator: Funamoto Satoru 同志社大学, 生命医科学部, 准教授 (10345043)
• Research Collaborator: Moniruzzaman Mohammad
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: アルツハイマー病 / アミロイド / セクレターゼ / 糖鎖修飾 / 基質選択性

Outline of Final Research Achievements

Nicastrin is one of components of γ-secretase complex, catalyzes the cleavage of amyloid precursor protein to generate amyloid-β protein (Aβ). NCT becomes matured through complex glycosylation and play important role in γ-secretase activity. However, the role of NCT glycosylation on γ-secretase activity and substrate specificity is still unknown. We investigated the effect of NCT glycosylation on γ-secretase activity and substrate specificity in a group of glycosylation mutant lectin resistant CHO (Lec) cells. CHO Lec-1 cells lack glycosyltransferase-I, thus N-glycan on NCT are all oligomannose type. We found that mutant CHO Lec-1 and Lec-2 reduced γ-secretase activity in both cell-based and biochemical assays, and that CHO Lec-1 preferentially reduced Aβ generation. Our data suggests that thorough glycosylation of NCT is critical for enzymatic activity and substrate preference of γ-secretase.

Free Research Field

神経病理学

Academic Significance and Societal Importance of the Research Achievements

アルツハイマー病予防・治療のためにγセクレターゼ活性を阻害すると、生体内の重要なタンパク質分解も阻害され重篤な副作用を引き起こす。Abの産生のみを阻害するγセクレターゼ阻害薬を開発するためには、この酵素の基質選択性の理解が必要である。この観点から、本研究は、γセクレターゼの基質選択決定に糖鎖が関与することをはじめて示すこととなり、この知見が今後創薬研究に活かされる可能性がある。