COPI complex is a regulator of lipid homeostasis

Nov 25, 2008

Magazine articles describing ways to burn fat, lose weight, etc. are omnipresent in Western culture, but science's understanding of the way fat is stored in the cells of the human body is rather slimmer.

In this week's issue of PLoS Biology, a new paper by Dr. Mathias Beller, Carole Sztalryd, and colleagues investigates some of the mysteries surrounding how our bodies store and release fat. Understanding lipid storage and use is important in tackling obesity and other metabolic disorders, and the authors identify a cellular pathway that regulates lipid storage, and show that interrupting it can reduce the amount of fat sequestered by our cells.

Fat is a major source of energy, and humans must consume a certain amount daily to remain healthy. Excess fat is stored in the cells of the body by converting the fatty acids found in food into droplets. These droplets then sit within a cell until the energy contained is required. The processes that create droplets and break them down again have previously been poorly understood. New work, led by Dr. Brian Oliver, of the National Institute of Diabetes and Digestive and Kidney Diseases in the USA, has identified some of the proteins that regulate the process, using first fruitflies and then mice, and have also identified chemicals that can perturb the pathway.

One protein family already know to be essential to lipid storage are the PAT proteins, which sit on the outside of the lipid droplet. Dr. Oliver and colleagues have identified another, somewhat surprising, key player – COPI (Coat Protein Complex I) transport complex, - already known to have a separate role in trafficking cellular components. The new study shows that PAT proteins are regulated by COPI; COPI acts to change the composition of the lipid droplet surface, attracting an enzyme called ATGL, which causes the droplet to be broken down. Therefore, COPI reduces the amount of lipid stored in a cell, releasing energy for movement and other activities. COPI acts to reduce the amount of PAT at the lipid droplet surface. An absence of some of the PAT proteins in mice or flies lead to lean animals, whereas greater than average expression of these proteins led to obese animals.

The authors found that COPI and PAT proteins have the same roles in energy storage in the fruit fly, Drosophila melanogaster, and in mammals such as mice and humans. This study hopes to open up further study of lipids and exploration of therapeutic possibilities for treating obesity and other metabolic disorders.

Citation: Beller M, Sztalryd C, Southall N, Bell M, Ja¨ckle H, et al. (2008) COPI complex is a regulator of lipid homeostasis. PLoS Biol 6(11): e292. doi:10.1371/journal.pbio.0060292
biology.plosjournals.org/perls… journal.pbio.0060292

Source: Public Library of Science

Explore further: Sea star disease strikes peninsula marine centers

add to favorites email to friend print save as pdf

Related Stories

Some motor proteins cooperate better than others

Jan 09, 2014

Rice University researchers have engineered cells to characterize how sensitively altering the cooperative functions of motor proteins can regulate the transport of organelles.

Cell biology: Flushing out fats

Dec 19, 2012

The Wip1 protein is important for survival, but mutations that inactivate it carry some surprising features. "A lack of Wip1 results in an excessive immune reaction to infectious organisms, in some cases ...

Recommended for you

Rare Sri Lankan leopards born in French zoo

1 hour ago

Two rare Sri Lankan leopard cubs have been born in a zoo in northern France, a boost for a sub-species that numbers only about 700 in the wild, the head of the facility said Tuesday.

Japan wraps up Pacific whale hunt

2 hours ago

Japan announced Tuesday that it had wrapped up a whale hunt in the Pacific, the second campaign since the UN's top court ordered Tokyo to halt a separate slaughter in the Antarctic.

Researchers uncover secrets of internal cell fine-tuning

2 hours ago

New research from scientists at the University of Kent has shown for the first time how the structures inside cells are regulated – a breakthrough that could have a major impact on cancer therapy development.

Getting a jump on plant-fungal interactions

2 hours ago

Fungal plant pathogens may need more flexible genomes in order to fully benefit from associating with their hosts. Transposable elements are commonly found with genes involved in symbioses.

User comments : 0