Control of BACE1 degradation and APP processing by ubiquitin carboxyl-terminal hydrolase L1.
Deposition of amyloid β protein (Aβ) in the brain is the hallmark of Alzheimer's disease (AD) pathogenesis. Beta-site amyloid precursor protein (APP) cleaving enzyme 1 (BACE1) is the β-secretase in vivo essential for generation of Aβ. Previously we demonstrated that BACE1 is ubiquitinated and the degradation of BACE1 is mediated by the ubiquitin-proteasome pathway (UPP). However the mechanism underlying regulation of BACE1 degradation by UPP remains elusive. Ubiquitin carboxyl-terminal hydrolase L1 (UCHL1) is a deubiquitinating enzyme highly specific to neuron, catalyzing the hydrolysis of ubiquitin conjugates from ubiquitinated substrates. UCHL1 regulates ubiquitin-dependent protein degradation. However, whether UCHL1 is particularly involved in the proteasomal degradation of BACE1 and what is the role of UCHL1 in AD pathogenesis remain elusive. To investigate the effect of UCHL1 on BACE1 degradation, HUCH cells, a UCHL1 stably over-expressed HEK293 cell line, was established. We found that inhibition of UCHL1 significantly increased BACE1 protein level in a time-dependent manner. Half life of BACE1 was reduced in HUCH cells compared with HEK. Over-expression of UCHL1 decreased APP C-terminal fragment C99 and Aβ levels in HUCH cells. Moreover, disruption of Uchl1 gene significantly elevated levels of endogenous BACE1, C99 and Aβ in the Uchl1-null gad mice. These results demonstrated that UCHL1 accelerates BACE1 degradation and affects APP processing and Aβ production. This study suggests that potentiation of UCHL1 might be able to reduce the level of BACE1 and Aβ in brain, which makes it a novel target for AD drug development.
Townsend Family Laboratories, Department of Psychiatry, Brain Research Center, Graduate Program in Neuroscience, The University of British Columbia, Vancouver, Canada.
Mingming
M
Zhang
Yu
Y
Deng
Yawen
Y
Luo
Shuting
S
Zhang
Haiyan
H
Zou
Fang
F
Cai
Keiji
K
Wada
Weihong
W
Song
D053829:Amyloid Precursor Protein Secretases / Q000378:metabolism*; D016229:Amyloid beta-Peptides / Q000378:metabolism; D016564:Amyloid beta-Protein Precursor / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D016282:Aspartic Acid Endopeptidases / Q000378:metabolism*; D002461:Cell Line, Transformed; D003513:Cycloheximide / Q000494:pharmacology; D004195:Disease Models, Animal; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay; D005786:Gene Expression Regulation / Q000187:drug effects / Q000235:genetics; D007211:Indoles / Q000494:pharmacology; D051379:Mice; D008818:Mice, Neurologic Mutants; D009154:Mutation / Q000235:genetics; D019150:Neuroaxonal Dystrophies / Q000235:genetics / Q000378:metabolism; D010091:Oximes / Q000494:pharmacology; D010446:Peptide Fragments / Q000378:metabolism; D011499:Protein Processing, Post-Translational / Q000187:drug effects / Q000235:genetics; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D013997:Time Factors; D014162:Transfection; D043222:Ubiquitin Thiolesterase / Q000235:genetics / Q000276:immunology / Q000378:metabolism*
D016229:Amyloid beta-Peptides; D016564:Amyloid beta-Protein Precursor; D000906:Antibodies; D004791:Enzyme Inhibitors; D007211:Indoles; C525086:LDN 57444; D010091:Oximes; D010446:Peptide Fragments; D011500:Protein Synthesis Inhibitors; C482860:UCHL1 protein, human; C078592:amyloid beta-protein (1-40); C075222:amyloid beta-protein (1-42); D003513:Cycloheximide; D053829:Amyloid Precursor Protein Secretases; D043222:Ubiquitin Thiolesterase; D016282:Aspartic Acid Endopeptidases; C509282:Bace1 protein, mouse