Scientists had previously identified the genes responsible for synthesizing fat within cells. But the genes governing the next step--packaging the fat inside a layer of phospholipids and proteins to form lipid droplets—have long been sought, and for good reason.
“Storing fat in lipid droplets appears crucially important for enabling cells to use fat as an energy source,” says Dr. David Silver, assistant professor of biochemistry at Einstein and senior author of the article. “From yeast to humans, partitioning fat into droplets is a universal feature among animals. And in humans, of course, acquiring excessive amounts of these fat droplets in our fat tissue leads to obesity.”
Dr. Silver and his colleagues identified two genes that are crucial for packaging fat into lipid droplets. They called the genes FIT1 and FIT2 (for Fat-Inducing Transcripts 1 and 2). Both genes code for proteins that are more than 200 amino acids in length, and the two genes are 50 percent similar to each other. The amino acid sequences of the FIT proteins do not resemble any other known proteins found in any species, indicating that the FIT genes comprise a novel gene family.
The researchers conducted several different experiments to confirm the roles of FIT1 and FIT2 in fat storage. In one experiment, they overexpressed both FIT1 and FIT2 genes (i.e., inserted extra copies of them) in human cells. While the rate of fat synthesis stayed the same in both “overexpressed” and control cells, the number of lipid droplets in the “overexpressed” cells increased dramatically, between four- and six-fold.
Using a different tactic to evaluate FIT function, the researchers next “knocked down” FIT2 in mouse fat cells (FIT1 is not expressed in these cells). Their reasoning: If FIT2 is indeed essential for lipid droplet formation, then suppressing FIT2 expression should abolish lipid-droplet accumulation. Examination of these fat cells for lipid droplets revealed that cells with suppressed FIT2 expression had a drastic reduction in lipid droplets.
Finally, the researchers carried out a similar FIT2 “knock down” experiment in a whole animal—the zebrafish. Zebrafish eggs were injected with a segment of DNA designed to interfere with FIT2 expression. Then, to induce lipid droplet formation in zebrafish larvae (where it is localized mainly in the liver and intestine), free-swimming six-day-old larvae were fed a high-fat diet for six hours. Although the larvae had exhibited normal feeding behavior, examination of their livers and intestines revealed a near-absence of lipid droplets.
“These lines of evidence supported our conclusion that FIT genes are necessary for the accumulation of lipid droplets in cells,” says Dr. Silver. “Now that we’ve identified the genes and the proteins they code for, it should be possible to develop drugs that can regulate their expression or activity. Such drugs could prove extremely valuable, not only for treating the main result of excess lipid droplet accumulation—obesity--but for alleviating the serious disorders that arise from obesity including type 2 diabetes and heart disease.”
Karen Gardner | EurekAlert!
Study suggests oysters offer hot spot for reducing nutrient pollution
17.10.2017 | Virginia Institute of Marine Science
World first for reading digitally encoded synthetic molecules
17.10.2017 | CNRS
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
It's possible to produce hydrogen to power fuel cells by extracting the gas from seawater, but the electricity required to do it makes the process costly. UCF...
17.10.2017 | Event News
10.10.2017 | Event News
10.10.2017 | Event News
17.10.2017 | Life Sciences
17.10.2017 | Physics and Astronomy
17.10.2017 | Life Sciences