title: Thermodynamic and structural destabilization of apoE3 by hereditary mutations associated with the development of lipoprotein glomerulopathy.
abstract: Lipoprotein glomerulopathy (LPG) is a dominant inherited kidney disorder characterized by lipoprotein thrombi in glomerular capillaries. Single-amino-acid mutations in apoE have been associated with the development of the disease, although the mechanism is unknown. In an effort to gain mechanistic insight linking the presence of such mutations and the development of LPG, we evaluated the effects of three of the most common apoE3 variants associated with this disease, namely R145P(Sendai), R147P(Chicago), and R158P(Osaka or Kurashiki), on the structural and conformational integrity of the protein. All three variants were found to have significantly reduced helical content, to expose a larger portion of hydrophobic surface to the solvent, and to be significantly thermodynamically destabilized, often lacking functionally relevant unfolding intermediates. Furthermore, all variants were aggregation prone and had enhanced sensitivity to protease digestion. Finally, although the variants were able to form discoidal lipoprotein particles, discrete subpopulations of poorly formed or aberrant particles were evident. Furthermore, these lipoprotein particles were thermodynamically destabilized and aggregation prone. Overall, our data suggest that these mutations induce a generalized unfolding of the N-terminal domain of apoE3 toward a molten-globule-like structure. ApoE3 N-terminal domain unfolding due to mutation may constitute a common mechanism underlying the protein's association with the pathogenesis of LPG.
authors.affiliation: National Centre for Scientific Research Demokritos, Agia Paraskevi, Athens 15310,  Greece.
authors.forename: Dimitra
authors.initials: D
authors.lastname: Georgiadou
authors.forename: Kostas
authors.initials: K
authors.lastname: Stamatakis
authors.forename: Eleni K
authors.initials: EK
authors.lastname: Efthimiadou
authors.forename: George
authors.initials: G
authors.lastname: Kordas
authors.forename: Donald
authors.initials: D
authors.lastname: Gantz
authors.forename: Angeliki
authors.initials: A
authors.lastname: Chroni
authors.forename: Efstratios
authors.initials: E
authors.lastname: Stratikos
mesh_terms: D053318:Apolipoprotein E3 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008076:Cholesterol, HDL / Q000737:chemistry / Q000378:metabolism; D004134:Dimyristoylphosphatidylcholine / Q000378:metabolism; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D007674:Kidney Diseases / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D007678:Kidney Glomerulus / Q000378:metabolism*; D008074:Lipoproteins / Q000378:metabolism*; D008958:Models, Molecular; D009154:Mutation; D010447:Peptide Hydrolases / Q000378:metabolism; D055503:Protein Multimerization; D055550:Protein Stability; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D013816:Thermodynamics
chemical_list: D053318:Apolipoprotein E3; D008076:Cholesterol, HDL; D008074:Lipoproteins; D010447:Peptide Hydrolases; D004134:Dimyristoylphosphatidylcholine