UCLA investigators have identified a new molecule that may help regulate the delivery of fats to cells for energy and storage.
Published in the April issue of the journal Cell Metabolism, the finding could lead to a better understanding of how we utilize fats from the foods we eat.
"We thought that we had figured out how the body digests and uses fats, but we have identified a completely new player in the game," said the study's author Anne Beigneux, assistant investigator at the David Geffen School of Medicine at UCLA.
Digested fats travel to the small intestine, where they are packaged into chylomicrons, which are large, spherical particles filled with triglycerides.
Chylomicrons then travel through the bloodstream and deliver triglycerides to the skeletal muscles and heart tissues that are hungry for fuel or to adipose tissue for energy storage. Molecules called proteoglycans, attached to the inside walls of capillaries, wait like baseball players with their mitts open, poised to catch the passing chylomicrons.
Proteoglycans hold the chylomicrons steady while the triglycerides are broken down or hydrolyzed by the enzyme lipoprotein lipase (LpL). The triglyceride breakdown products are then taken up and used by cells.
"Previously we didn't know what molecule in the capillaries facilitated the capture of chylomicrons and facilitated the interaction with lipoprotein lipase," said Dr. Stephen Young, study author and investigator at the David Geffen School of Medicine at UCLA. "We think that we've found the missing piece of the puzzle."
Investigators discovered that a protein called glycosylphosphatidylinositol-anchored high-density lipoprotein-binding protein 1 (GPIHBP1) may be the missing link.
Scientists found that mice deficient in GPIHBP1 develop very high triglyceride levels, even on a normal diet, demonstrating that fats in the bloodstream are not readily metabolized
Contact: Rachel Champeau
University of California - Los Angeles