Publications by authors named "Jeffrey A Julien"

3 Publications

  • Page 1 of 1

Preparation and characterization of neutrally-buoyant oleosin-rich synthetic lipid droplets.

Biochim Biophys Acta Biomembr 2021 Aug 30;1863(8):183624. Epub 2021 Apr 30.

Department of Chemistry, Lehigh University, 6 E. Packer Ave. Bethlehem, PA 18015, USA. Electronic address:

Lipid droplets also known as oil bodies are found in a variety of organisms and function as stores of high-energy metabolites. Recently, there has been interest in using lipid droplets for protein production and drug delivery. Artificial lipid droplets have been previously prepared, but their short lifetime in solution and inhomogeneity has severely limited their applicability. Herein we report an improved methodology for the production of synthetic lipid droplets that overcomes the aforementioned limitations. These advancements include: 1) development of a methodology for the expression and purification of high-levels of oleosin, a crucial lipid droplet component, 2) preparation of neutrally-buoyant synthetic lipid droplets, and 3) production of synthetic lipid droplets of a specific size. Together, these important enhancements will facilitate the advancement of lipid droplet science and its application in biotechnology.
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http://dx.doi.org/10.1016/j.bbamem.2021.183624DOI Listing
August 2021

Preparation of Caveolin-1 for NMR Spectroscopy Experiments.

Methods Mol Biol 2020 ;2169:137-147

Department of Chemistry, Lehigh University, Bethlehem, PA, USA.

Caveolin-1 is a 20.5 kDa integral membrane protein that is involved in a myriad of cellular processes including signal transduction, relieving mechano-stresses on the cell, endocytosis, and most importantly caveolae formation. As a consequence, there is intense interest in characterizing caveolin-1 structurally. Out of the many available structural techniques, nuclear magnetic resonance (NMR) spectroscopy is particularly well suited to investigations on integral membrane proteins like caveolin-1 that have significant unstructured regions and unusual topologies. However, the technique requires relatively large amounts of protein (i.e. concentrations in the 0.5-5 mM range), and obtaining these amounts can be difficult especially for highly hydrophobic membrane proteins such as caveolin-1. Herein, we describe a robust protocol for the preparation of caveolin-1 for structural studies using NMR.
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http://dx.doi.org/10.1007/978-1-0716-0732-9_13DOI Listing
March 2021

Secondary structure of caveolins: a mini review.

Biochem Soc Trans 2019 10;47(5):1489-1498

Department of Chemistry, Lehigh University, 6 E. Packer Ave, Bethlehem, PA 18015, U.S.A.

Caveolae are 50-100 nm invaginations found within the plasma membrane of cells. Caveolae are involved in many processes that are essential for homeostasis, most notably endocytosis, mechano-protection, and signal transduction. Within these invaginations, the most important proteins are caveolins, which in addition to participating in the aforementioned processes are structural proteins responsible for caveolae biogenesis. When caveolin is misregulated or mutated, many disease states can arise which include muscular dystrophy, cancers, and heart disease. Unlike most integral membrane proteins, caveolin does not have a transmembrane orientation; instead, it is postulated to adopt an unusual topography where both the N- and C-termini lie on the cytoplasmic side of the membrane, and the hydrophobic span adopts an intramembrane loop conformation. While knowledge concerning the biology of caveolin has progressed apace, fundamental structural information has proven more difficult to obtain. In this mini-review, we curate as well as critically assess the structural data that have been obtained on caveolins to date in order to build a robust and compelling model of the caveolin secondary structure.
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http://dx.doi.org/10.1042/BST20190375DOI Listing
October 2019