Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Newly discovered 'platform' for processing dietary fat

05.04.2007
A new "platform" with a crucial role in the body's ability to process and take up fat from the diet has been found, according to a report in the April issue of the journal Cell Metabolism, published by Cell Press.

Researchers discovered a protein that sits on the inner surfaces of capillaries, where it delivers "packages" of dietary fat from the bloodstream to enzymes that prepare them for entry into cells of the body. Once inside cells, the fats are either burned as a rich source of energy or stored for later use.

"We've found a new, very important partner in a process people thought they understood 20 years ago," said Anne Beigneux of the University of California, Los Angeles.

While it is too soon to say whether the finding will have clinical implications—in efforts to limit the body's capacity to store fat, for instance—one thing is for certain: "Soon, every biochemistry book will have to be revised," she said.

Dietary fats in mammals are packaged by the intestine into "chylomicrons," which are large triglyceride-rich lipoproteins, Beigneux explained. After reaching the bloodstream, the triglycerides within chylomicrons are broken down by an enzyme found along the surface of capillaries, mainly in the heart, skeletal muscle, and fat tissue. In those tissues, the so-called lipoprotein lipase enzyme is synthesized, secreted, and transported to the capillaries, where the packaged lipids are taken apart.

The fat "bundles" have to be broken down because the lipids are otherwise unable to get across cell membranes, Beigneux added.

The researchers "stumbled onto" a new player in the process after a team at Genentech found mutant mice with severe chylomicronemia, a condition in which the inability to properly process dietary fat leads to high levels of blood triglycerides.

The mice—which lacked a gene called glycosylphosphatidylinositol-anchored high-density lipoprotein-binding protein 1, or Gpihbp1—exhibited a striking accumulation of chylomicrons in the plasma, even on a low-fat diet, the researchers report. The animals' deficiency caused their blood plasma to become milky as their blood triglyceride levels skyrocketed. Normally, the lipoprotein-binding protein is found at high levels in heart and adipose tissue, the same tissues that express high levels of the enzyme that breaks chylomicrons down, they report.

The researchers conclude that GPIHBP1 is crucial for chylomicron processing. It is located on the inner surface of the capillary and binds both chylomicrons and the processing enzyme, likely forming a platform for lipid breakdown and playing an important role in the delivery of lipid nutrients to cells.

The findings might have direct implications for patients with chylomicronemia, Beigneux said. The disorder in humans has been linked only to defects in the genes encoding the lipid-degrading enzyme or its cofactor, she explained.

"Now, anybody who has chylomicronemia without one of those mutations should be looked at for a mutation in [this platform protein, GPIHBP1]," she said.

Erin Doonan | EurekAlert!
Further information:
http://www.cell.com

Further reports about: Beigneux HDL-cholesterol Triglyceride chylomicron

More articles from Life Sciences:

nachricht NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation

nachricht Pollen taxi for bacteria
18.07.2018 | Technische Universität München

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

NYSCF researchers develop novel bioengineering technique for personalized bone grafts

18.07.2018 | Life Sciences

Machine-learning predicted a superhard and high-energy-density tungsten nitride

18.07.2018 | Materials Sciences

Why might reading make myopic?

18.07.2018 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>