The mammalian cholesterol synthesis enzyme squalene monooxygenase is proteasomally truncated to a constitutively active form.
cholesterol
endoplasmic reticulum–associated protein degradation
proteasome
protein degradation
squalene monooxygenase
ubiquitylation (ubiquitination)
Journal
The Journal of biological chemistry
ISSN: 1083-351X
Titre abrégé: J Biol Chem
Pays: United States
ID NLM: 2985121R
Informations de publication
Date de publication:
Historique:
received:
16
10
2020
revised:
24
04
2021
accepted:
28
04
2021
pubmed:
3
5
2021
medline:
1
9
2021
entrez:
2
5
2021
Statut:
ppublish
Résumé
Squalene monooxygenase (SM, also known as squalene epoxidase) is a rate-limiting enzyme of cholesterol synthesis that converts squalene to monooxidosqualene and is oncogenic in numerous cancer types. SM is subject to feedback regulation via cholesterol-induced proteasomal degradation, which depends on its lipid-sensing N-terminal regulatory domain. We previously identified an endogenous truncated form of SM with a similar abundance to full-length SM, but whether this truncated form is functional or subject to the same regulatory mechanisms as full-length SM is not known. Here, we show that truncated SM differs from full-length SM in two major ways: it is cholesterol resistant and adopts a peripheral rather than integral association with the endoplasmic reticulum membrane. However, truncated SM retains full SM activity and is therefore constitutively active. Truncation of SM occurs during its endoplasmic reticulum-associated degradation and requires the proteasome, which partially degrades the SM N-terminus and disrupts cholesterol-sensing elements within the regulatory domain. Furthermore, truncation relies on a ubiquitin signal that is distinct from that required for cholesterol-induced degradation. Using mutagenesis, we demonstrate that partial proteasomal degradation of SM depends on both an intrinsically disordered region near the truncation site and the stability of the adjacent catalytic domain, which escapes degradation. These findings uncover an additional layer of complexity in the post-translational regulation of cholesterol synthesis and establish SM as the first eukaryotic enzyme found to undergo proteasomal truncation.
Identifiants
pubmed: 33933449
pii: S0021-9258(21)00520-2
doi: 10.1016/j.jbc.2021.100731
pmc: PMC8166775
pii:
doi:
Substances chimiques
Cholesterol
97C5T2UQ7J
Squalene Monooxygenase
EC 1.14.14.17
Proteasome Endopeptidase Complex
EC 3.4.25.1
Types de publication
Journal Article
Research Support, Non-U.S. Gov't
Langues
eng
Sous-ensembles de citation
IM
Pagination
100731Informations de copyright
Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.
Déclaration de conflit d'intérêts
Conflict of interest The authors declare that they have no conflicts of interest with the contents of this article.
Références
Nat Methods. 2015 Oct;12(10):955-8
pubmed: 26322837
Curr Top Dev Biol. 2017;123:277-302
pubmed: 28236969
Mol Cell Biol. 1996 May;16(5):2248-54
pubmed: 8628291
Methods Enzymol. 1996;266:554-71
pubmed: 8743706
Intrinsically Disord Proteins. 2013 Apr 1;1(1):e24428
pubmed: 28516009
Nature. 2019 Mar;567(7746):118-122
pubmed: 30760928
Cancer Res. 2016 Aug 15;76(16):4785-90
pubmed: 27325648
Biochem J. 2019 Sep 20;476(18):2545-2560
pubmed: 31471528
Biochem J. 2014 Aug 1;461(3):435-42
pubmed: 24840124
Nucleic Acids Res. 2018 Jul 2;46(W1):W329-W337
pubmed: 29860432
Nat Rev Mol Cell Biol. 2008 Feb;9(2):125-38
pubmed: 18216769
Biochem Biophys Res Commun. 2016 Jan 22;469(4):1123-8
pubmed: 26703208
EMBO J. 1991 Dec;10(13):4159-67
pubmed: 1756723
Mol Cell Biol. 2014 Apr;34(7):1262-70
pubmed: 24449766
Lancet. 2007 Dec 1;370(9602):1829-39
pubmed: 18061058
Nat Commun. 2019 Jan 11;10(1):166
pubmed: 30635583
Nature. 2002 Sep 26;419(6905):403-7
pubmed: 12353037
Nucleic Acids Res. 2015 Jan;43(Database issue):D512-20
pubmed: 25514926
Cancer Res. 2016 Apr 15;76(8):2063-70
pubmed: 27197250
Nucleic Acids Res. 2007 Jul;35(Web Server issue):W460-4
pubmed: 17567614
Proc Natl Acad Sci U S A. 2020 Mar 31;117(13):7150-7158
pubmed: 32170014
J Cell Biol. 1982 Apr;93(1):97-102
pubmed: 7068762
Cell. 2013 Aug 29;154(5):983-995
pubmed: 23993092
Cell Metab. 2011 Mar 2;13(3):260-73
pubmed: 21356516
Nat Struct Mol Biol. 2004 Sep;11(9):830-7
pubmed: 15311270
Nat Commun. 2019 Jan 9;10(1):97
pubmed: 30626872
IUBMB Life. 2014 May;66(5):309-17
pubmed: 24823973
J Biol Chem. 2014 Jul 4;289(27):19053-66
pubmed: 24860107
J Biol Chem. 2019 May 17;294(20):8134-8147
pubmed: 30940729
J Cell Sci. 2007 Feb 15;120(Pt 4):682-91
pubmed: 17264153
Methods Enzymol. 1983;98:241-60
pubmed: 6321901
Biosci Rep. 2014 Apr 1;34(2):
pubmed: 27919032
Bioinformatics. 2000 Oct;16(10):915-22
pubmed: 11120681
Cell. 2000 Feb 18;100(4):423-34
pubmed: 10693759
J Biol Chem. 1995 Apr 7;270(14):8172-8
pubmed: 7713922
BMC Bioinformatics. 2017 Nov 13;18(1):476
pubmed: 29132292
Chem Phys Lipids. 2016 Sep;199:170-178
pubmed: 26993747
Proc Natl Acad Sci U S A. 2006 Jun 20;103(25):9482-7
pubmed: 16769897
Proc Natl Acad Sci U S A. 2003 Oct 14;100(21):12027-32
pubmed: 14512514
Proc Natl Acad Sci U S A. 2020 Apr 14;117(15):8228-8230
pubmed: 32238557
Nat Struct Mol Biol. 2016 Sep;23(9):778-85
pubmed: 27428775
Dev Cell. 2018 Jan 8;44(1):97-112.e7
pubmed: 29275994
J Biol Chem. 2017 Dec 8;292(49):19959-19973
pubmed: 28972164
Gastroenterology. 2021 Mar;160(4):1194-1207.e28
pubmed: 32946903
J Biol Chem. 2007 Apr 13;282(15):10846-52
pubmed: 17283082
J Biol Chem. 2004 Feb 27;279(9):8487-96
pubmed: 14660594
Biol Chem. 2011 Dec;392(12):1053-75
pubmed: 22050222
Nat Commun. 2018 Nov 30;9(1):5123
pubmed: 30504772
J Biochem. 2019 May 28;:
pubmed: 31135054
Nat Protoc. 2008;3(6):1101-8
pubmed: 18546601
Sci Rep. 2016 Jan 18;6:19435
pubmed: 26777065
Cell. 2001 Nov 30;107(5):667-77
pubmed: 11733065
Nucleic Acids Res. 2017 Jan 4;45(D1):D158-D169
pubmed: 27899622
Methods Mol Biol. 2009;498:91-103
pubmed: 18988020
Proc Natl Acad Sci U S A. 2018 Aug 28;115(35):E8172-E8180
pubmed: 30104359
Toxicol Appl Pharmacol. 2020 Aug 15;401:115103
pubmed: 32522582
EMBO J. 2000 Sep 1;19(17):4712-22
pubmed: 10970863
Elife. 2020 Jun 26;9:
pubmed: 32588820
Bioinformatics. 2017 Mar 1;33(5):685-692
pubmed: 28011771
J Biol Chem. 2015 Nov 13;290(46):27533-44
pubmed: 26434806
Carcinogenesis. 2017 Aug 1;38(8):806-811
pubmed: 28595267
Nat Struct Mol Biol. 2006 Aug;13(8):691-7
pubmed: 16845392
J Biol Chem. 2008 Jan 11;283(2):700-7
pubmed: 17981807
Biochim Biophys Acta Mol Cell Biol Lipids. 2017 Jul;1862(7):647-657
pubmed: 28342963
Biotechniques. 2010 Jun;48(6):463-5
pubmed: 20569222
Nat Methods. 2007 Mar;4(3):251-6
pubmed: 17293868
Proc Natl Acad Sci U S A. 1997 Nov 11;94(23):12616-21
pubmed: 9356498
Arch Biochem Biophys. 2000 Feb 15;374(2):381-8
pubmed: 10666321
Methods Mol Biol. 2003;211:365-9
pubmed: 12489444
Science. 2015 Sep 18;349(6254):1356-8
pubmed: 26383956
Oncogene. 2018 Aug;37(34):4750-4768
pubmed: 29765154
Nat Struct Mol Biol. 2005 Dec;12(12):1045-53
pubmed: 16299518
Mol Biol Cell. 2018 May 1;29(9):1021-1030
pubmed: 29514927
Sci Transl Med. 2018 Apr 18;10(437):
pubmed: 29669855
Mol Cell. 2009 Oct 9;36(1):28-38
pubmed: 19818707
Cell. 1999 Aug 6;98(3):305-16
pubmed: 10458606
J Biol Chem. 2016 Aug 26;291(35):18547-61
pubmed: 27405762
Bioinformatics. 2016 Sep 1;32(17):i672-i679
pubmed: 27587688
BMC Bioinformatics. 2006 Apr 17;7:208
pubmed: 16618368
Nat Commun. 2019 Jan 9;10(1):96
pubmed: 30626880
Nature. 1991 Dec 5;354(6352):395-8
pubmed: 1956402
Bioinformatics. 2015 Mar 15;31(6):857-63
pubmed: 25391399
J Biol Chem. 2016 Jul 15;291(29):15082-92
pubmed: 27226596
Cell. 2000 Sep 1;102(5):577-86
pubmed: 11007476
Nat Rev Mol Cell Biol. 2015 Jan;16(1):18-29
pubmed: 25531225
PLoS One. 2013 Dec 23;8(12):e83888
pubmed: 24376768