Apolipoprotein E3 (apoE3) plays a role in the metabolism of lipoproteins and lowers plasma lipid levels by serving as a ligand for the low density lipoprotein receptor (LDLr) family of proteins and by promoting macrophage cholesterol efflux. The current study examines the effect of acrolein modification on the structure and function of apoE3. Acrolein modification was confirmed in immunoblots by reactivity with acrolein-lysine-specific antibody and by the presence of oligomeric species due to crosslinking. Mass spectrometry revealed modification of K75 (propanal adduct) and K157 (MP-lysine). Circular dichroism spectroscopy showed no major change in overall secondary structure compared to unmodified apoE3. Acrolein-modified apoE3 showed loss of binding to soluble LDLr; however, incubation with mouse endothelioma bEnd.3 cells showed that it was internalized. Incubation with excess LDL did not abolish cellular uptake of acrolein-modified apoE3, suggesting alternative mechanism(s) not involving LDLr. Incubation with anti-CD36 antibody did not show a decrease in internalization while incubation with anti-LOX1 showed partial internalization. However, incubation with anti-SRB1 antibody abolished internalization of acrolein-modified apoE3. Taken together, our studies suggest that acrolein modification of apoE3 at lysine residues involved directly or indirectly with lipoprotein receptor interaction may impair its role in regulating plasma cholesterol homeostasis and eventually lead to lipid metabolic disorders.
|Commitee:||Bhandari, Deepali, Fraser, Deborah|
|School:||California State University, Long Beach|
|Department:||Chemistry and Biochemistry|
|School Location:||United States -- California|
|Source:||MAI 58/04M(E), Masters Abstracts International|
|Keywords:||Acrolein, Apolipoprotein E3, Oxidative stress, Scavenger receptors|
Copyright in each Dissertation and Thesis is retained by the author. All Rights Reserved
The supplemental file or files you are about to download were provided to ProQuest by the author as part of a
dissertation or thesis. The supplemental files are provided "AS IS" without warranty. ProQuest is not responsible for the
content, format or impact on the supplemental file(s) on our system. in some cases, the file type may be unknown or
may be a .exe file. We recommend caution as you open such files.
Copyright of the original materials contained in the supplemental file is retained by the author and your access to the
supplemental files is subject to the ProQuest Terms and Conditions of use.
Depending on the size of the file(s) you are downloading, the system may take some time to download them. Please be