CoChat
Sign Up
Cited by 4Alzheimer's disease research and treatmentsProtein Structure and DynamicsLipid Membrane Structure and Behavior

Conformational analysis of apolipoprotein E3/E4 heteromerization

Open access
Tu, Kai‐Han, Abhari, Devan, Narayanaswami, Vasanthy·2019·The FEBS Journal
DOI 10.1111/febs.14794PMC PMC6733585
Open this paper in CoChat — free account

Abstract

Apolipoprotein E (apoE) is a 299 residue, exchangeable apolipoprotein that has essential roles in cholesterol homeostasis and reverse cholesterol transport. It is a two‐domain protein with the C‐terminal (CT) domain mediating protein self‐association via helix‐helix interactions. In humans, the APOE gene is polymorphic with three common alleles, ε2, ε3, and ε4, occurring in frequencies of ~ 5%, 77%, and 18%, respectively. Heterozygotes expressing apoE3 and apoE4 isoforms, which differ in residue at position 112 in the N‐terminal domain (C112 in apoE3 and R112 in apoE4), represent the highest population of ε4 carriers, an allele highly associated with Alzheimer's disease. The objective of this study was to determine if apoE3 and apoE4 have the ability to hybridize to form a heteromer in lipid‐free state. Refolding an equimolar mixture of His‐apoE3 and FLAG‐apoE4 (or vice versa) followed by pull‐down and immunoblotting indicated formation of apoE3/apoE4 heteromers. Förster resonance energy transfer between donor fluorophore on one isoform and acceptor on the other, both located in the respective CT domains, revealed a distance of separation of ~ 46 Å between the donor/acceptor pair. Similarly, a quencher placed on one was able to mediate significant quenching of fluorescence emission on the other, indicative of spatial proximity within collisional distance between the two. ApoE3/apoE4 heteromer association was also noted in lipid‐associated state in reconstituted lipoprotein particles. The possibility of heteromerization of apoE3/apoE4 bears implications in the potential mitigating role of apoE3 on the folding and physiological behavior of apoE4 and its role in maintaining cholesterol homeostasis.

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

Integrity signals

Registry

Crossref · 10.1111/febs.14794

Cites

9 of 9 references verified0 citation errors · 0 not checkable

Statistics

Claims the paper makes

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • ApoE3/ApoE4 heterodimers adopt conformations distinct from either homodimer.

    “ApoE3/ApoE4 heterodimers have been shown to adopt conformations distinct from either homodimer (46).”

    From APOE Isoform-Dependent Self-Association Measured by a Split-Luciferase Complementation Assay: Differential Effects of Disease-Risk and Protective Variants (2026) · cites this paper as [46]

    The Results and Discussion report apoE3/apoE4 heteromer formation. But the Discussion says the data cannot discriminate among apoE3/apoE3, apoE4/apoE4, and apoE3/apoE4 dimeric configurations; it does not establish that heterodimers adopt conformations distinct from either homodimer. Page numbers are unavailable in our copy. (LLM, conf=0.88)

    Experimental — accuracy not yet measured

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

The self-check needs the paper’s full text.

Cites

Flagged first, then by citations

Research works printed but not linked: 49

  1. [1]Mahley RW (2017) Apolipoprotein E: Remarkable Protein Sheds Light on Cardiovascular and Neurological Diseases. Clin. Chem 63, 14– 20. 28062606
  2. [2]Mahley RW (2016) Apolipoprotein E: from cardiovascular disease to neurodegenerative disorders. J. Mol. Med. Berl. Ger 94, 739– 746. PMC4921111 27277824
  3. [4]Mahley RW (1988) Apolipoprotein E: cholesterol transport protein with expanding role in cell biology. Science 240, 622– 30. 3283935
  4. [5]Utermann G, Hees M & Steinmetz A (1977) Polymorphism of apolipoprotein E and occurrence of dysbetalipoproteinaemia in man. Nature 269, 604– 607. 199847
  5. [6]Mahley RW & Rall SC (2000) Apolipoprotein E: far more than a lipid transport protein. Annu. Rev. Genomics Hum. Genet 1, 507– 537. 11701639
  6. [8]Davignon J, Gregg RE & Sing CF (1988) Apolipoprotein E polymorphism and atherosclerosis. Arterioscler. Thromb. Vasc. Biol 8, 1– 21. 3277611
  7. [9]Hill JM, Bhattacharjee PS & Neumann DM (2007) Apolipoprotein E alleles can contribute to the pathogenesis of numerous clinical conditions including HSV-1 corneal disease. Exp. Eye Res 84, 801– 11. 17007837 PMC2217677
  8. [10]Verghese PB, Castellano JM & Holtzman DM (2011) Apolipoprotein E in Alzheimer’s disease and other neurological disorders. Lancet Neurol 10, 241– 252. 21349439 PMC3132088
  9. [11]Corder EH, Saunders AM, Strittmatter WJ, Schmechel DE, Gaskell PC, Small GW, Roses AD, Haines JL & Pericak-Vance MA (1993) Gene dose of apolipoprotein E type 4 allele and the risk of Alzheimer’s disease in late onset families. Science 261, 921– 923. 8346443
  10. [12]Saunders AM, Strittmatter WJ, Schmechel D, George-Hyslop PH, Pericak-Vance MA, Joo SH, Rosi BL, Gusella JF, Crapper-MacLachlan DR & Alberts MJ (1993) Association of apolipoprotein E allele epsilon 4 with late-onset familial and sporadic Alzheimer’s disease. Neurology 43, 1467– 1472. 8350998
  11. [13]Saunders AM (2000) Apolipoprotein E and Alzheimer disease: an update on genetic and functional analyses. J. Neuropathol. Exp. Neurol 59, 751– 758. 11005255
  12. [14]Corder EH, Saunders AM, Strittmatter WJ, Schmechel DE, Gaskell PC, Rimmler JB, Locke PA, Conneally PM, Schmader KE & Tanzi RE (1995) Apolipoprotein E, survival in Alzheimer’s disease patients, and the competing risks of death and Alzheimer’s disease. Neurology 45, 1323– 1328. 7617191
  13. [16]Finch CE & Sapolsky RM (1999) The evolution of Alzheimer disease, the reproductive schedule, and apoE isoforms. Neurobiol. Aging 20, 407– 428. 10604433
  14. [17]Finch CE & Stanford CB (2004) Meat-adaptive genes and the evolution of slower aging in humans. Q. Rev. Biol 79, 3– 50. 15101252
  15. [20]Dong LM, Wilson C, Wardell MR, Simmons T, Mahley RW, Weisgraber KH & Agard DA (1994) Human apolipoprotein E. Role of arginine 61 in mediating the lipoprotein preferences of the E3 and E4 isoforms. J. Biol. Chem 269, 22358– 22365. 8071364
  16. [22]Chen J, Li Q & Wang J (2011) Topology of human apolipoprotein E3 uniquely regulates its diverse biological functions. Proc. Natl. Acad. Sci. U. S. A 108, 14813– 14818. 21873229 PMC3169138
  17. [23]Morrow JA, Arnold KS, Dong J, Balestra ME, Innerarity TL & Weisgraber KH (2000) Effect of arginine 172 on the binding of apolipoprotein E to the low density lipoprotein receptor. J. Biol. Chem 275, 2576– 2580. 10644716
  18. [24]Dong LM, Parkin S, Trakhanov SD, Rupp B, Simmons T, Arnold KS, Newhouse YM, Innerarity TL & Weisgraber KH (1996) Novel mechanism for defective receptor binding of apolipoprotein E2 in type III hyperlipoproteinemia. Nat. Struct. Biol 3, 718– 722. 8756331
  19. [25]Wilson C, Mau T, Weisgraber KH, Wardell MR, Mahley RW & Agard DA (1994) Salt bridge relay triggers defective LDL receptor binding by a mutant apolipoprotein. Struct. Lond. Engl 1993 2, 713– 718. 7994571
  20. [26]Dong LM & Weisgraber KH (1996) Human apolipoprotein E4 domain interaction. Arginine 61 and glutamic acid 255 interact to direct the preference for very low density lipoproteins. J. Biol. Chem 271, 19053– 19057. 8702576
  21. [27]Tran TN, Kim SH, Gallo C, Amaya M, Kyees J & Narayanaswami V (2013) Biochemical and biophysical characterization of recombinant rat apolipoprotein E: similarities to human apolipoprotein E3. Arch. Biochem. Biophys 529, 18– 25. 23103361 PMC3543869
  22. [28]Perugini MA, Schuck P & Howlett GJ (2000) Self-association of human apolipoprotein E3 and E4 in the presence and absence of phospholipid. J. Biol. Chem 275, 36758– 36765. 10970893
  23. [29]Morrow JA, Segall ML, Lund-Katz S, Phillips MC, Knapp M, Rupp B & Weisgraber KH (2000) Differences in stability among the human apolipoprotein E isoforms determined by the amino-terminal domain. Biochemistry 39, 11657– 11666. 10995233
  24. [30]Wetterau JR, Aggerbeck LP, Rall SC & Weisgraber KH (1988) Human apolipoprotein E3 in aqueous solution. I. Evidence for two structural domains. J. Biol. Chem 263, 6240– 6248. 3360781
  25. [31]Gupta V, Narayanaswami V, Budamagunta MS, Yamamato T, Voss JC & Ryan RO (2006) Lipid-induced extension of apolipoprotein E helix 4 correlates with low density lipoprotein receptor binding ability. J. Biol. Chem 281, 39294– 39299. 17079229
  26. [32]Nichols AV, Gong EL, Blanche PJ, Forte TM & Shore VG (1987) Pathways in the formation of human plasma high density lipoprotein subpopulations containing apolipoprotein A-I without apolipoprotein A-II. J. Lipid Res 28, 719– 732. 3112299
  27. [33]Kim SH, Kothari S, Patel AB, Bielicki JK & Narayanaswami V (2014) A pyrene based fluorescence approach to study conformation of apolipoprotein E3 in macrophage-generated nascent high density lipoprotein. Biochem. Biophys. Res. Commun 450, 124– 128. 24866239 PMC4130211
  28. [34]Narayanaswami V, Maiorano JN, Dhanasekaran P, Ryan RO, Phillips MC, Lund-Katz S & Davidson WS (2004) Helix orientation of the functional domains in apolipoprotein e in discoidal high density lipoprotein particles. J. Biol. Chem 279, 14273– 14279. 14739281
  29. [35]Bekris LM, Yu C-E, Bird TD & Tsuang DW (2010) Review Article: Genetics of Alzheimer Disease. J. Geriatr. Psychiatry Neurol 23, 213– 227. 21045163 PMC3044597
  30. [36]Fukumoto H, Ingelsson M, Gårevik N, Wahlund L-O, Nukina N, Yaguchi Y, Shibata M, Hyman BT, Rebeck GW & Irizarry MC (2003) APOE ε3/ε4 heterozygotes have an elevated proportion of apolipoprotein E4 in cerebrospinal fluid relative to plasma, independent of Alzheimer’s disease diagnosis. Exp. Neurol 183, 249– 253. 12957508
  31. [37]Von Eckardstein A, Langer C, Engel T, Schaukal I, Cignarella A, Reinhardt J, Lorkowski S, Li Z, Zhou X, Cullen P & Assmann G (2001) ATP binding cassette transporter ABCA1 modulates the secretion of apolipoprotein E from human monocyte-derived macrophages. FASEB J. Off. Publ. Fed. Am. Soc. Exp. Biol 15, 1555– 1561. 11427487
  32. [38]Ruiz J, Kouiavskaia D, Migliorini M, Robinson S, Saenko EL, Gorlatova N, Li D, Lawrence D, Hyman BT, Weisgraber KH & Strickland DK (2005) The apoE isoform binding properties of the VLDL receptor reveal marked differences from LRP and the LDL receptor. J. Lipid Res 46, 1721– 1731. 15863833
  33. [40]Mahley RW & Huang Y (2012) Small-molecule structure correctors target abnormal protein structure and function: structure corrector rescue of apolipoprotein E4-associated neuropathology. J. Med. Chem 55, 8997– 9008. 23013167 PMC4904786
  34. [41]Yokoyama S, Kawai Y, Tajima S & Yamamoto A (1985) Behavior of human apolipoprotein E in aqueous solutions and at interfaces. J. Biol. Chem 260, 16375– 16382. 4066713
  35. [43]Fukumoto H, Ingelsson M, Gårevik N, Wahlund LO, Nukina N, Yaguchi Y, Shibata M, Hyman BT, Rebeck GW & Irizarry MC (2003) APOE ε3/ε4 heterozygotes have an elevated proportion of apolipoprotein E4 in cerebrospinal fluid relative to plasma, independent of Alzheimer’s disease diagnosis. Exp. Neurol 183, 249– 253. 12957508
  36. [45]Rezeli M, Zetterberg H, Blennow K, Brinkmalm A, Laurell T, Hansson O & Marko-Varga G (2015) Quantification of total apolipoprotein E and its specific isoforms in cerebrospinal fluid and blood in Alzheimer’s disease and other neurodegenerative diseases.. PMC7020540 32054532
  37. [46]Phillips MC (2014) Molecular mechanisms of cellular cholesterol efflux. J. Biol. Chem 289, 24020– 24029. 25074931 PMC4148835
  38. [47]Tanaka M, Vedhachalam C, Sakamoto T, Dhanasekaran P, Phillips MC, Lund-Katz S & Saito H (2006) Effect of Carboxyl-Terminal Truncation on Structure and Lipid Interaction of Human Apolipoprotein E4 †. Biochemistry 45, 4240– 4247. 16566598
  39. [48]Sakamoto T, Tanaka M, Vedhachalam C, Nickel M, Nguyen D, Dhanasekaran P, Phillips MC, Lund-Katz S & Saito H (2008) Contributions of the Carboxyl-Terminal Helical Segment to the Self-Association and Lipoprotein Preferences of Human Apolipoprotein E3 and E4 Isoforms †. Biochemistry 47, 2968– 2977. 18201068 PMC2692928
  40. [49]Choy N, Raussens V & Narayanaswami V (2003) Inter-molecular coiled-coil formation in human apolipoprotein E C-terminal domain. J. Mol. Biol 334, 527– 539. 14623192
  41. [50]Matko J, Ohki K & Edidin M (1992) Luminescence quenching by nitroxide spin labels in aqueous solution: studies on the mechanism of quenching. Biochemistry 31, 703– 11. 1731926
  42. [51]Merkle H, Subczynski WK & Kusumi A (1987) Dynamic fluorescence quenching studies on lipid mobilities in phosphatidylcholine-cholesterol membranes. Biochim. Biophys. Acta BBA - Biomembr 897, 238– 248. 3028480
  43. [52]Peters-Libeu CA, Newhouse Y, Hall SC, Witkowska HE & Weisgraber KH (2007) Apolipoprotein E&dipalmitoylphosphatidylcholine particles are ellipsoidal in solution 1. J Lipid Res 48, 1035– 1044. 17308333
  44. [53]Garai K, Baban B & Frieden C (2011) Self-Association and Stability of the ApoE Isoforms at Low pH: Implications for ApoE–Lipid Interactions. Biochemistry 50, 6356– 6364. 21699199
  45. [54]Khumsupan P, Ramirez R, Khumsupan D & Narayanaswami V (2011) Apolipoprotein E LDL receptor-binding domain-containing high-density lipoprotein: A nanovehicle to transport curcumin, an antioxidant and anti-amyloid bioflavonoid. Biochim. Biophys. Acta BBA - Biomembr 1808, 352– 359. PMC2997894 20851099
  46. [55]Mamotte CD, Sturm M, Foo JI, van Bockxmeer FM & Taylor RR (1999) Comparison of the LDL-receptor binding of VLDL and LDL from apoE4 and apoE3 homozygotes. Am. J. Physiol 276, E553– 557. 10070023
  47. [56]Strickland DK, Gonias SL & Argraves WS (2002) Diverse roles for the LDL receptor family. Trends Endocrinol. Metab. TEM 13, 66– 74. 11854021
  48. [57]Hashimoto T, Serrano-Pozo A, Hori Y, Adams KW, Takeda S, Banerji AO, Mitani A, Joyner D, Thyssen DH, Bacskai BJ, Frosch MP, Spires-Jones TL, Finn MB, Holtzman DM & Hyman BT (2012) Apolipoprotein E, Especially Apolipoprotein E4, Increases the Oligomerization of Amyloid Peptide. J. Neurosci 32, 15181– 15192. 23100439 PMC3493562
  49. [58]Lek MT, Cruz S, Ibe NU, Beck WHJ, Bielicki JK, Weers PMM & Narayanaswami V (2017) Swapping the N- and C-terminal domains of human apolipoprotein E3 and AI reveals insights into their structure/activity relationship. PloS One 12, e0178346. 28644829 PMC5482431

Cited by

Sorted by citations

Authors
Tu, K., Abhari, D., & Narayanaswami, V.
Affiliations
California State University, Long Beach (US)
Corresponding author
Narayanaswami, Vasanthy
ORCID
Venue
The FEBS Journal
Publisher
Wiley
Published
2019-03-13
Volume
286
Issue
10
Pages
1986-1998
ISSN
  • 1742-464X (ISSN-L)
  • 1742-4658
DOI
10.1111/febs.14794
PMC
PMC6733585
OpenAlex
W2915262148
Cited by
4
References
9
Citations by year
2026: 2 · 2024: 1 · 2023: 1
FWCI
0.00
Type
journal article
Language
en
Open access
Licence
onlinelibrary.wiley.com/termsAndConditions#vor (vor)
Locations
  • FEBS Journal (publishedVersion)
  • PubMed (publishedVersion)
  • PubMed Central (acceptedVersion)
Funders
National Institute of General Medical Sciences (GM105561)
Topics
  • Health Sciences › Medicine › Physiology › Alzheimer's disease research and treatments
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Protein Structure and Dynamics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Lipid Membrane Structure and Behavior
Keywords
apolipoprotein E, APOE3, APOE ε4, conformational analysis, C-terminal domain, helix-helix interactions, APOE polymorphism, Alzheimer's disease, cholesterol homeostasis, reverse cholesterol transport, protein-protein interaction, fluorescence resonance energy transfer
MeSH terms
Circular Dichroism, Fluorescence, Humans, Phosphatidylcholines, Protein Conformation, Protein Denaturation, Fluorescence Resonance Energy Transfer, Apolipoprotein E3, Apolipoprotein E4, Protein Interaction Domains and Motifs, Protein Multimerization

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review