Disruption of the ERLIN–TM6SF2–APOB complex destabilizes APOB and contributes to non-alcoholic fatty liver disease

Autoři: Bo-Tao Li aff001;  Ming Sun aff001;  Yun-Feng Li aff001;  Ju-Qiong Wang aff001;  Zi-Mu Zhou aff001;  Bao-Liang Song aff001;  Jie Luo aff001
Působiště autorů: Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China aff001
Vyšlo v časopise: Disruption of the ERLIN–TM6SF2–APOB complex destabilizes APOB and contributes to non-alcoholic fatty liver disease. PLoS Genet 16(8): e32767. doi:10.1371/journal.pgen.1008955
Kategorie: Research Article
doi: 10.1371/journal.pgen.1008955


Non-alcoholic fatty liver disease (NAFLD) is a metabolic disorder characterized by excess lipid accumulation in the liver without significant consumption of alcohol. The transmembrane 6 superfamily member 2 (TM6SF2) E167K missense variant strongly associates with NAFLD in humans. The E167K mutation destabilizes TM6SF2, resulting in hepatic lipid accumulation and low serum lipid levels. However, the molecular mechanism by which TM6SF2 regulates lipid metabolism remains unclear. By using tandem affinity purification in combination with mass spectrometry, we found that apolipoprotein B (APOB), ER lipid raft protein (ERLIN) 1 and 2 were TM6SF2-interacting proteins. ERLINs and TM6SF2 mutually bound and stabilized each other. TM6SF2 bound and stabilized APOB via two luminal loops. ERLINs did not interact with APOB directly but still increased APOB stability through stabilizing TM6SF2. This APOB stabilization was hampered by the E167K mutation that reduced the protein expression of TM6SF2. In mice, knockout of Tm6sf2 and knockdown of Tm6sf2 or Erlins decreased hepatic APOB protein level, causing lipid accumulation in the liver and lowering lipid levels in the serum. We conclude that defective APOB stabilization, as a result of ERLINs or TM6SF2 deficiency or E167K mutation, is a key factor contributing to NAFLD.

Klíčová slova:

Fatty liver – Cholesterol – Immunoblotting – Immunoprecipitation – Lipids – Oils – Small interfering RNA – Transfection


1. Younossi Z, Anstee QM, Marietti M. Hardy T, Henry L, Eslam M, et al. Global burden of NAFLD and NASH: trends, predictions, risk factors and prevention. Nature Reviews Gastroenterology & Hepatology 2018; 15:11–20.

2. Trico D, Caprio S, Rosaria Umano G, Pierpont B, Nouws J, Galderisi A, et al. Metabolic features of nonalcoholic fatty liver (NAFL) in obese adolescents: Findings from a multiethnic cohort. Hepatology 2018; 68: 1376–1390. doi: 10.1002/hep.30035 29665034

3. Younossi ZM, Koenig AB, Abdelatif D, Fazel Y, Henry L, Wymer M, et al. Global epidemiology of nonalcoholic fatty liver disease-Meta-analytic assessment of prevalence, incidence, and outcomes. Hepatology 2016; 64:73–84. doi: 10.1002/hep.28431 26707365

4. Chen L, Chen XW, Huang X, Song BL, Wang Y, Wang Y. Regulation of glucose and lipid metabolism in health and disease. Science China-Life Sciences 2019; 62:1420–1458. doi: 10.1007/s11427-019-1563-3 31686320

5. Michelotti GA, Machado MV, Diehl AM. NAFLD, NASH and liver cancer. Nature Reviews Gastroenterology & Hepatology 2013; 10:656–665.

6. Kanwal F, Jennifer R Kramer, Srikar Mapakshi, Natarajan Y, Chayanupatkul M, Richardson PA, et al. Risk of hepatocellular cancer in patients with non-alcoholic fatty liver disease. Gastroenterology 2018; 155:1828–1837 e1822. doi: 10.1053/j.gastro.2018.08.024 30144434

7. Lonardo A, Ballestri S, Marchesini G, Angulo P, Loria P. Nonalcoholic fatty liver disease: a precursor of the metabolic syndrome. Digestive and Liver Disease 2015; 47:181–190. doi: 10.1016/j.dld.2014.09.020 25739820

8. Yki-Jarvinen H. Non-alcoholic fatty liver disease as a cause and a consequence of metabolic syndrome. Lancet Diabetes & Endocrinology 2014; 2:901–910.

9. Yilmaz Y. NAFLD in the absence of metabolic syndrome: different epidemiology, pathogenetic mechanisms, risk factors for disease progression? Seminars In Liver Disease 2012; 32:14–21. doi: 10.1055/s-0032-1306422 22418884

10. Holmen OL, Zhang H, Fan Y, Hovelson DH, Schmidt EM, Zhou W, et al. Systematic evaluation of coding variation identifies a candidate causal variant in TM6SF2 influencing total cholesterol and myocardial infarction risk. Nature Genetics 2014; 46:345–351. doi: 10.1038/ng.2926 24633158

11. Kozlitina J, Smagris E, Stender S, Nordestgaard BG, Zhou HH, Tybjærg-Hansen A, et al. Exome-wide association study identifies a TM6SF2 variant that confers susceptibility to nonalcoholic fatty liver disease. Nature Genetics 2014; 46: 352–356. doi: 10.1038/ng.2901 24531328

12. Mahdessian H, Taxiarchis A, Popov S, Silveira A, Franco-Cereceda A, Hamsten A, et al. TM6SF2 is a regulator of liver fat metabolism influencing triglyceride secretion and hepatic lipid droplet content. Proceedings of the National Academy of Sciences of the United States of America 2014; 111:8913–8918. doi: 10.1073/pnas.1323785111 24927523

13. Smagris E, Gilyard S, BasuRay S, Cohen JC, Hobbs HH. Inactivation of Tm6sf2, a gene defective in fatty liver disease, impairs lipidation but not secretion of very low density lipoproteins. Journal of Biological Chemistry 2016; 291:10659–10676. doi: 10.1074/jbc.M116.719955 27013658

14. Ehrhardt N, Doche ME, Chen S, Mao HZ, Walsh MT, Bedoya C, et al. Hepatic Tm6sf2 overexpression affects cellular ApoB-trafficking, plasma lipid levels, hepatic steatosis and atherosclerosis. Human Molecular Genetics 2017; 26:2719–2731. doi: 10.1093/hmg/ddx159 28449094

15. Fan Y Lu, Haocheng, Guo Yanhong, Zhu T, Garcia-Barrio MT, Jiang Z, et al. Hepatic transmembrane 6 superfamily member 2 regulates cholesterol metabolism in mice. Gastroenterology 2016, 150: 1208–1218. doi: 10.1053/j.gastro.2016.01.005 26774178

16. Prill S, Caddeo A, Baselli G, Jamialahmadi O, Dongiovanni P, Rametta R, et al. The TM6SF2 E167K genetic variant induces lipid biosynthesis and reduces apolipoprotein B secretion in human hepatic 3D spheroids. Scientific Reports 2019; 9:11585. doi: 10.1038/s41598-019-47737-w 31406127

17. Browman DT, Resek ME, Zajchowski LD, Robbins SM. Erlin-1 and erlin-2 are novel members of the prohibitin family of proteins that define lipid-raft-like domains of the ER. Journal of Cell Science 2006; 119:3149–3160. doi: 10.1242/jcs.03060 16835267

18. Pearce MM, Wormer DB, Wilkens S, Wojcikiewicz RJ J. An endoplasmic reticulum (ER) membrane complex composed of SPFH1 and SPFH2 mediates the ER-associated degradation of inositol 1,4,5-trisphosphate receptors. Journal of Biological Chemistry 2009; 284:10433–10445. doi: 10.1074/jbc.M809801200 19240031

19. Jo Y, Sguigna PV, Debose-Boyd RA. Membrane-associated ubiquitin ligase complex containing gp78 mediates sterol-accelerated degradation of 3-hydroxy-3-methylglutaryl-coenzyme A reductase. Journal of Biological Chemistry 2011; 286:15022–15031. doi: 10.1074/jbc.M110.211326 21343306

20. Huber MD, Vesely PW, Datta K, Gerace L. Erlins restrict SREBP activation in the ER and regulate cellular cholesterol homeostasis. Journal of Cell Biology 2013; 203:427–436. doi: 10.1083/jcb.201305076 24217618

21. Feitosa MF, Wojczynski MK, North KE, Zhang Q, Province MA, Carr JJ, et al. The ERLIN1-CHUK-CWF19L1 gene cluster influences liver fat deposition and hepatic inflammation in the NHLBI Family Heart Study. Atherosclerosis 2013; 228:175–180. doi: 10.1016/j.atherosclerosis.2013.01.038 23477746

22. Edelman D, Harmit Kalia, Maria Delio, Alani M, Krishnamurthy K, Abd M, et al. Genetic analysis of nonalcoholic fatty liver disease within a Caribbean-Hispanic population. Molecular Genetics & Genomic Medicine 2015; 3:558–569.

23. Greeve J, Altkemper I, Dieterich JH, Greten H, Windler E. Apolipoprotein B mRNA editing in 12 different mammalian species: hepatic expression is reflected in low concentrations of apoB-containing plasma lipoproteins. Journal of Lipid Research 1993; 34:1367–1383. 8409768

24. Koornneef A, Maczuga P, van Logtenstein R, Borel F, Blits B, Ritsema T, et al. Apolipoprotein B knockdown by AAV-delivered shRNA lowers plasma cholesterol in mice. Molecular Therary 2011; 19:731–740.

25. Wang YJ, Bian Y, Luo J, Lu M, Xiong Y, Guo SY, et al. Cholesterol and fatty acids regulate cysteine ubiquitylation of ACAT2 through competitive oxidation. Nature Cell Biology 2017; 19:808–819. doi: 10.1038/ncb3551 28604676

26. Donati B. Motta BM, Pingitore P, Meroni M, Pietrelli A, Alisi A, et al. The rs2294918 E434K variant modulates patatin-like phospholipase domain-containing 3 expression and liver damage. Hepatology 2016; 63:787–98. doi: 10.1002/hep.28370 26605757

27. Gong XM, Li YF, Luo J, Wang JQ, Wei J, Wang JQ, et al. Gpnmb secreted from liver promotes lipogenesis in white adipose tissue and aggravates obesity and insulin resistance. Nature Metabolism 2019; 1: 570–583. doi: 10.1038/s42255-019-0065-4 32694855

28. Liu TF, Tang JJ, Li PS, Shen Y, Li JG, Miao HH, et al. Ablation of gp78 in liver improves hyperlipidemia and insulin resistance by inhibiting SREBP to decrease lipid biosynthesis. Cell Metabolism 2012; 16:213–25. doi: 10.1016/j.cmet.2012.06.014 22863805

29. Romeo S, Kozlitina J, Xing C, Pertsemlidis A, Cox D, Pennacchio LA, Boerwinkle E, et al. Genetic variation in PNPLA3 confers susceptibility to nonalcoholic fatty liver disease. Nature Genetics 2008; 40:1461–1465. doi: 10.1038/ng.257 18820647

30. Speliotes EK, Laura M, Yerges-Armstrong, Hernaez R, Kim LJ, Palmer CD, et al. Genome-wide association analysis identifies variants associated with nonalcoholic fatty liver disease that have distinct effects on metabolic traits. PLOS Genetics 2011; 7:3.

31. Tang JJ, Li JG, Qi W, Qiu WW, Li PS, Li BL, et al. Inhibition of SREBP by a small molecule, betulin, improves hyperlipidemia and insulin resistance and reduces atherosclerotic plaques. Cell Metabolism 2011; 13:44–56. doi: 10.1016/j.cmet.2010.12.004 21195348

32. Wang X, Liu Z, Wang K, Wang Z, Sun X, Zhong L, et al. Additive effects of the risk alleles of PNPLA3 and TM6SF2 on non-alcoholic fatty liver disease (NAFLD) in a Chinese population. Frontiers in Genetics 2016; 7:140. doi: 10.3389/fgene.2016.00140 27532011

33. Goffredo M, Sonia Caprio, Ariel E Feldstein, D'Adamo E, Shaw MM, Pierpont B, et al. Role of TM6SF2 rs58542926 in the pathogenesis of nonalcoholic pediatric fatty liver disease: A multiethnic study. Hepatology 2016; 63:117–125. doi: 10.1002/hep.28283 26457389

34. Stender S, Kozlitina J, Nordestgaard BG, Tybjærg-Hansen A, Hobbs HH, Cohen JC, et al. Adiposity amplifies the genetic risk of fatty liver disease conferred by multiple loci. Nature Genetics 2017; 49:842–847. doi: 10.1038/ng.3855 28436986

35. Dongiovanni P, Salvatore Petta, Cristina Maglio, Fracanzani AL, Pipitone R, Mozzi E, et al. Transmembrane 6 superfamily member 2 gene variant disentangles nonalcoholic steatohepatitis from cardiovascular disease. Hepatology 2015; 61:506–514. doi: 10.1002/hep.27490 25251399

36. Kim DS, Anne U Jackson, Yatong KLi, Stringham HM, FinMetSeq Investigators, Kuusisto J, et al. Novel association of TM6SF2 rs58542926 genotype with increased serum tyrosine levels and decreased apoB-100 particles in Finns. Journal of Lipid Research 2017; 58:471–1481.

37. Wang X, Guo M, Wang Q, Wang Q, Zuo S, Zhang X, et al. The patatin-like phospholipase domain containing protein 7 facilitates VLDL secretion by modulating ApoE stability. Hepatology 2020; doi: 10.1002/hep.31161 32103509

38. Chen L, Ma MY, Sun M, Jiang LY, Zhao XT, Fang XX, et al. Endogenous sterol intermediates of the mevalonate pathway regulate HMGCR degradation and SREBP-2 processing. Journal of Lipid Research 2019; 60:1765–1775. doi: 10.1194/jlr.RA119000201 31455613

39. Luukkonen PK, Zhou Y, Nidhina Haridas PA, Dwivedi OP, Hyötyläinen T, Ali A, et al. Impaired hepatic lipid synthesis from polyunsaturated fatty acids in TM6SF2 E167K variant carriers with NAFLD. Journal of Hepatology 2017; 67:128–136. doi: 10.1016/j.jhep.2017.02.014 28235613

40. Luo J, Yang H, Song BL. Mechanisms and regulation of cholesterol homeostasis. Nature Reviews Molecular Cell Biology 2020; 21:225–245. doi: 10.1038/s41580-019-0190-7 31848472

41. Ge L, Wang J, Qi W, Miao HH, Cao J, Qu YX, et al. The cholesterol absorption inhibitor ezetimibe acts by blocking the sterol-induced internalization of NPC1L1. Cell Metabolism 2008; 7:508–519. doi: 10.1016/j.cmet.2008.04.001 18522832

42. Zhang YY, Fu ZY, Wei J, Qi W, Baituola G, Luo J, et al. A LIMA1 variant promotes low plasma LDL cholesterol and decreases intestinal cholesterol absorption. Science 2018; 360:1087–1092. doi: 10.1126/science.aao6575 29880681

43. Xiao J, Luo J, Hu A, Xiao T, Li M, Kong Z, et al. Cholesterol transport through the peroxisome-ER membrane contacts tethered by PI(4,5)P2 and extended synaptotagmins. Science China-Life Sciences 2019; 62:1117–1135. doi: 10.1007/s11427-019-9569-9 31144242

Článek vyšel v časopise

PLOS Genetics

2020 Číslo 8

Nejčtenější v tomto čísle
Kurzy Podcasty Doporučená témata Časopisy
Zapomenuté heslo

Nemáte účet?  Registrujte se

Zapomenuté heslo

Zadejte e-mailovou adresu, se kterou jste vytvářel(a) účet, budou Vám na ni zaslány informace k nastavení nového hesla.


Nemáte účet?  Registrujte se