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.

"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 July 25, 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 July 25, 2014).

Share This




More Health & Medicine News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

New Painkiller Designed To Discourage Abuse: Will It Work?

New Painkiller Designed To Discourage Abuse: Will It Work?

Newsy (July 24, 2014) The FDA approved Targiniq ER on Wednesday, a painkiller designed to keep users from abusing it. Like any new medication, however, it has doubters. Video provided by Newsy
Powered by NewsLook.com
Doctor At Forefront Of Fighting Ebola Outbreak Gets Ebola

Doctor At Forefront Of Fighting Ebola Outbreak Gets Ebola

Newsy (July 24, 2014) Sheik Umar Khan has treated many of the people infected in the Ebola outbreak, and now he's become one of them. Video provided by Newsy
Powered by NewsLook.com
Condemned Man's US Execution Takes Nearly Two Hours

Condemned Man's US Execution Takes Nearly Two Hours

AFP (July 24, 2014) America's death penalty debate raged Thursday after it took nearly two hours for Arizona to execute a prisoner who lost a Supreme Court battle challenging the experimental lethal drug cocktail. Duration: 00:55 Video provided by AFP
Powered by NewsLook.com
Can Watching TV Make You Feel Like A Failure?

Can Watching TV Make You Feel Like A Failure?

Newsy (July 24, 2014) A study by German researchers claims watching TV while you're stressed out can make you feel guilty and like a failure. 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:
from the past week

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