Type
Text
Type
Thesis
Advisor
Brown, Deborah A | London, Erwin
Date
2011-12-01
Keywords
Biochemistry
Department
Department of Biochemistry and Cell Biology
Language
en_US
Source
This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree.
Identifier
http://hdl.handle.net/11401/71315
Publisher
The Graduate School, Stony Brook University: Stony Brook, NY.
Format
application/pdf
Abstract
Cholesterol biosynthesis regulation via the SREBP (sterol regulatory element binding protein) pathway has previously been elucidated to exhibit a switch-like response in the ER at ~ 5 mol% cholesterol. It has been proposed that this threshold value is mainly due to the control of the concentration at which cholesterol becomes accessible by the phospholipid composition of the ER membrane. We have conducted experiments to investigate this hypothesis. Perfringolysin O (PFO) was applied as a sterol sensor that binds membranes and oligomerizes upon cholesterol exposure in artificial membranes. Using this system, we detected a progressive enhancement of cholesterol accessibility as more PE (phosphatidylethanolamine) and PS (phosphatidylserine) phospholipids were incorporated into SUVs composed of PC (phosphatidylcholine). Further studies involving the uptake of various biologically relevant fatty intercalants (triglycerides, diglycerides, fatty alcohols) into PE/PS-containing vesicles reduced the threshold to a value as low as 2 mol% cholesterol. We discuss the hypothetical contributions of PE, PS, and various fatty intercalants in lowering the threshold concentration at which the SREBP pathway decides to transcriptionally activate or deactivate cholesterol biosynthesis. | 47 pages
Recommended Citation
Lee, Caroline, "Enhanced cholesterol accessibility for PFO interaction in membranes containing POPE and POPS phospholipids." (2011). Stony Brook Theses and Dissertations Collection, 2006-2020 (closed to submissions). 521.
https://commons.library.stonybrook.edu/stony-brook-theses-and-dissertations-collection/521