Undergraduate Honors Thesis Projects

Date of Award

Spring 2023

Document Type

Honors Paper

Department

Biochemistry and Molecular Biology

Advisor

Dr. John Tansey

First Committee Member

Dr. John Tansey

Second Committee Member

Dr. Brandon Sinn

Third Committee Member

Dr. Cynthia Laurie-Rose

Keywords

Perilipin 5, Lipid Droplet, Actin, Microtubules, Lipid, Immunofluorescence

Subject Categories

Biochemistry

Abstract

Lipid metabolism is the basis of many metabolic diseases that are effecting the US. A rise in the body’s free fatty acids can occur in diseases like diabetes mellitus and metabolic syndrome, which results in oxidative stress in the mitochondria. In the cell, there are lipid storage droplets that store triacylglycerol and cholesterol esters. On the surface of these droplets the PAT family of proteins can be found, which are involved in the regulation of lipolysis in multiple different ways. Perilipin 5 is a part of this family and is expressed in tissues that have a higher capacity for fatty acid oxidation. While on the lipid droplet, perilipin 5 interacts with ATGL or HSL to regulate lipolysis. Perilipin 5 is phosphorylated by PKA and is found to form a transcriptional complex in the nucleus with PGC-1α and SIRT1 to mediate mitochondrial biogenesis and oxidative function. When in a fasting state, this complex changes the oxidative capacity of the mitochondria so that the increased flux of fatty acids does not damage the cell. This important protective pathway helps protect the cell from damage, yet how this protein initially gets to the nucleus is unknown. There are two common routes for intracellular trafficking, either through actin filaments or microtubules. Cytochalasin B and colchicine were the drugs used to inhibit the dynamics of actin filaments and microtubules, respectively. After one of the cytoskeletal elements was inhibited, the cells were stimulated and the effects of the inhibition on perilipin 5’s movement was examined through immunofluorescent immunochemistry, cell fractioning studies, and immunoprecipitations. The data from the immunofluorescence pointed to a negative result for the use of actin in the translocation to the nucleus and was inconclusive for the use of microtubules. The cell fractioning study and the immunoprecipitation indicated inconclusive results and need further optimization. This study is able to provide information to further the study of intracellular trafficking of perilipin.

Licensing Permission

Copyright, all rights reserved. Fair Use

Acknowledgement 2

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Available for download on Tuesday, April 20, 2027

Included in

Biochemistry Commons

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