Scavenger protein receptor aids the transport of lipoproteins
Lipoproteins are spherical molecules made up of fat and proteins that play a crucial role in transporting lipids, such as cholesterol and triglycerides, from the liver to other tissues in the body. Anton Potapenko of the University of Zurich, and a team in Switzerland recently published a in the Journal of Lipid Research detailing structural characteristics of the scavenger receptor B1, or SCARB1, a protein that mediates lipid exchange between many cell types and facilitates uptake of high density lipoproteins, or HDL, and low density lipoproteins, or LDL, in some cell types. The gene encoding SCARB1 produces two major splice variants that share structural similarities but differ in their carboxy-terminal domains. Researchers wanted to understand if these splice variants play different roles in the cellular uptake of LDL and HDL by endothelial cells.

The researchers examined cultured endothelial cells to understand how expression of the two SCARB1 variants affected the binding, uptake and trafficking of lipoproteins. They found that variants 1 and 2 localized to the cell surface, and endosomes and lysosomes, respectively. Overexpression of variant 1 increased both HDL and LDL binding and uptake. However, overexpression of variant 2 also increased the uptake of either lipoprotein, but not via surface binding. Therefore, the researchers concluded that variant 2 facilitates lipoprotein uptake indirectly by regulatory and indirect mechanisms.
The study suggests that the two major splice variants of SCARB1 facilitate transendothelial transport of HDL and LDL by different mechanisms, either dependent or independent of the adapter proteins. Because of the limitations of overexpression, it will be important to examine how eliminating each SCARB1 splice variant affects cellular lipid metabolism and lipoprotein trafficking.
Enjoy reading ASBMB Today?
Become a member to receive the print edition four times a year and the digital edition monthly.
Learn moreGet the latest from ASBMB Today
Enter your email address, and we’ll send you a weekly email with recent articles, interviews and more.
Latest in Science
Science highlights or most popular articles

Targeting toxins to treat whooping cough
Scientists find that liver protein inhibits of pertussis toxin, offering a potential new treatment for bacterial respiratory disease. Read more about this recent study from the Journal of Biological Chemistry.

Elusive zebrafish enzyme in lipid secretion
Scientists discover that triacylglycerol synthesis enzyme drives lipoproteins secretion rather than lipid droplet storage. Read more about this recent study from the Journal of Biological Chemistry.

Scientists identify pan-cancer biomarkers
Researchers analyze protein and RNA data across 13 cancer types to find similarities that could improve cancer staging, prognosis and treatment strategies. Read about this recent article published in Molecular & Cellular Proteomics.

New mass spectrometry tool accurately identifies bacteria
Scientists develop a software tool to categorize microbe species and antibiotic resistance markers to aid clinical and environmental research. Read about this recent article published in Molecular & Cellular Proteomics.

New tool matches microbial and metabolic metaproteomic data
Scientists develop a bioinformatics program that maps omics data to metabolic pathways. Read about this recent article published in Molecular & Cellular Proteomics

Meet Paul Shapiro
Learn how the JBC associate editor went from milking cows on a dairy farm to analyzing kinases in the lab.