Featured Research

from universities, journals, and other organizations

New Role For Protein In Fat Cells May Improve Understanding Of Obesity And Diabetes

Date:
July 20, 2007
Source:
American Society for Biochemistry and Molecular Biology
Summary:
Scientists have shown for the first time that a protein involved in the transfer of fat in the blood may also influence how fat cells store fat. They have shown that the protein, called cholesteryl ester transfer protein, is involved in the cellular storage and regulation of cholesterol and other fats and, as a result, probably has unexpected contributions to obesity and diabetes.

Scientists have shown for the first time that a protein involved in the transfer of fat in the blood may also influence how fat cells store fat. Richard E. Morton and Lahoucine Izem, research scientists at the Cleveland Clinic Foundation, have shown that the protein, called cholesteryl ester transfer protein (CETP), is involved in the cellular storage and regulation of cholesterol and other fats and, as a result, probably has unexpected contributions to obesity and diabetes.

Related Articles


"CETP is known to shuttle different types of fat between lipoproteins -- combinations of fat and protein that transport fats in the blood," Morton says. "In this study, we show that CETP also shuttles fats inside fat cells between two separate areas and that fat cells with reduced levels of CETP are unable to process fats normally."

Research performed during the past decade has shown that CETP affects how a type of fat called cholesteryl ester is moved from the blood plasma into cells. Since fat cells make abundant CETP, Morton and Izem decided to examine what CETP does inside a fat cell and what would happen to fat cells that are deficient in CETP.

The scientists noticed that fat cells lacking CETP could not make and store cholesterol, cholesteryl ester, and another fat called triglyceride like normal fat cells do. In CETP-deficient cells, cholesteryl ester and triglyceride accumulated in a cellular compartment called the endoplasmic reticulum (ER), while an abnormally low amount of these fats was seen in "lipid droplets" -- local accumulations of fat in fat cells.

Morton and Izem suggest that, in normal cells, CETP transfers cholesteryl ester and triglyceride from the ER, where they are made, to the lipid droplets, where they are stored. In cells lacking CETP, only a fraction of both fats is carried from the ER to the lipid droplets. Also, since cholesterol is produced by breaking down cholesteryl ester in lipid droplets, lower levels of cholesteryl ester lead to smaller amounts of cholesterol in the droplets.

"CETP-deficient cells have unbalanced amounts of cholesterol and fats," Morton says. "They have too much cholesteryl ester and triglycerides in the ER and not enough of them in the lipid droplets. Also, these cells sense that they have too much cholesterol, although they actually have low amounts of cholesterol. Overall, the cells don't correctly control the amount of fats they make and store anymore."

A consequence of the abnormal distribution of fats between cell compartments is that cholesteryl ester and triglycerides cannot be used easily. In normal cells, when these two fats accumulate in the droplets, they can be removed from the droplets and then used by the cell after the fats are broken down by enzymes called hydrolases. But since hydrolases are in the droplets and not in the ER, cells low in CETP cannot break down the fats they store as effectively, Morton and Izem say.

The scientists conclude that CETP is probably essential for lipid metabolism and storage in fat cells and that fat tissue is not only an energy storage tissue but also a major endocrine organ.

"CETP deficiency disrupts storage of important fats in fat cells, which can lead to insulin resistance -- a major contributor to diabetes -- and the abnormal release of cytokines, proteins that stimulate the immune system," Morton says. "This unexpected contribution of CETP provides a new understanding of how our body stores and regulates fats and of conditions such as obesity and diabetes."

The new study is to be published in the July 27 issue of the Journal of Biological Chemistry.

Article: "Possible Role for Intracellular Cholesteryl Ester Transfer Protein in Adipocyte Lipid Metabolism and Storage," by Lahoucine Izem and Richard E. Morton


Story Source:

The above story is based on materials provided by American Society for Biochemistry and Molecular Biology. Note: Materials may be edited for content and length.


Cite This Page:

American Society for Biochemistry and Molecular Biology. "New Role For Protein In Fat Cells May Improve Understanding Of Obesity And Diabetes." ScienceDaily. ScienceDaily, 20 July 2007. <www.sciencedaily.com/releases/2007/07/070719164536.htm>.
American Society for Biochemistry and Molecular Biology. (2007, July 20). New Role For Protein In Fat Cells May Improve Understanding Of Obesity And Diabetes. ScienceDaily. Retrieved November 24, 2014 from www.sciencedaily.com/releases/2007/07/070719164536.htm
American Society for Biochemistry and Molecular Biology. "New Role For Protein In Fat Cells May Improve Understanding Of Obesity And Diabetes." ScienceDaily. www.sciencedaily.com/releases/2007/07/070719164536.htm (accessed November 24, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Monday, November 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Ebola-Hit Sierra Leone's Late Cocoa Leaves Bitter Taste

Ebola-Hit Sierra Leone's Late Cocoa Leaves Bitter Taste

AFP (Nov. 23, 2014) The arable district of Kenema in Sierra Leone -- at the centre of the Ebola outbreak in May -- has been under quarantine for three months as the cocoa harvest comes in. Duration: 01:32 Video provided by AFP
Powered by NewsLook.com
Don't Fall For Flu Shot Myths

Don't Fall For Flu Shot Myths

Newsy (Nov. 23, 2014) Misconceptions abound when it comes to your annual flu shot. Medical experts say most people older than 6 months should get the shot. Video provided by Newsy
Powered by NewsLook.com
WFP: Ebola Risks Heightened Among Women Throughout Africa

WFP: Ebola Risks Heightened Among Women Throughout Africa

AFP (Nov. 21, 2014) Having children has always been a frightening prospect in Sierra Leone, the world's most dangerous place to give birth, but Ebola has presented an alarming new threat for expectant mothers. Duration: 00:37 Video provided by AFP
Powered by NewsLook.com
Could Your Genes Be The Reason You're Single?

Could Your Genes Be The Reason You're Single?

Newsy (Nov. 21, 2014) Researchers in Beijing discovered a gene called 5-HTA1, and carriers are reportedly 20 percent more likely to be single. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins