RRC ID 47257
Author Kizuka Y, Nakano M, Kitazume S, Saito T, Saido TC, Taniguchi N.
Title Bisecting GlcNAc modification stabilizes BACE1 protein under oxidative stress conditions.
Journal Biochem. J.
Abstract β-Site amyloid precursor protein-cleaving enzyme-1 (BACE1) is a protease essential for amyloid-β (Aβ) production in Alzheimer's disease (AD). BACE1 protein is known to be up-regulated by oxidative stress-inducing stimuli but the mechanism for this up-regulation still needs to be clarified. We have recently found that BACE1 is modified with bisecting N-acetylglucosamine (GlcNAc) by N-acetylglucosaminyltransferase-III (GnT-III, encoded by the Mgat3 gene) and that GnT-III deficiency reduces Aβ-plaque formation in the brain by accelerating lysosomal degradation of BACE1. Therefore, we hypothesized that bisecting GlcNAc would stabilize BACE1 protein on oxidative stress. In the present study, we first show that Aβ deposition in the mouse brain induces oxidative stress, together with an increase in levels of BACE1 and bisecting GlcNAc. Furthermore, prooxidant treatment induces expression of BACE1 protein in wild-type mouse embryonic fibroblasts (MEFs), whereas it reduces BACE1 protein in GnT-III (Mgat3) knock-out MEFs by accelerating lysosomal degradation of BACE1. We purified BACE1 from Neuro2A cells and performed LC/ESI/MS analysis for BACE1-derived glycopeptides and mapped bisecting GlcNAc-modified sites on BACE1. Point mutations at two N-glycosylation sites (Asn(153) and Asn(223)) abolish the bisecting GlcNAc modification on BACE1. These mutations almost cancelled the enhanced BACE1 degradation seen in Mgat3(-/-) MEFs, indicating that bisecting GlcNAc on BACE1 indeed regulates its degradation. Finally, we show that traumatic brain injury-induced BACE1 up-regulation is significantly suppressed in the Mgat3(-/-) brain. These results highlight the role of bisecting GlcNAc in oxidative stress-induced BACE1 expression and offer a novel glycan-targeted strategy for suppressing Aβ generation.
Volume 473(1)
Pages 21-30
Published 2016-1-1
DOI 10.1042/BJ20150607
PII BJ20150607
PMID 26467158
MeSH Acetylglucosamine / biosynthesis* Acetylglucosamine / genetics Amyloid Precursor Protein Secretases / biosynthesis* Animals Aspartic Acid Endopeptidases / biosynthesis* Brain / metabolism Brain / pathology Brain Injuries / genetics Brain Injuries / metabolism Brain Injuries / pathology Cell Line, Transformed Cell Line, Tumor Male Mice Mice, Inbred C57BL Mice, Knockout Oxidative Stress / physiology*
IF 3.857
Times Cited 7
DNA material pcDNA6/hBACE1 deltaTM-myc-His (RDB14343) pCAGGS/hBACE1 N153S (RDB14344) pCAGGS/hBACE1 N172S (RDB14345) pCAGGS/hBACE1 N223S (RDB14346) pCAGGS/hBACE1 N354S (RDB14347) pCAGGS/hBACE1 N153 223S (RDB14348).