Featured Research

from universities, journals, and other organizations

Researchers identify scaffold regulating protein disposal

Date:
January 5, 2010
Source:
Helmholtz Association of German Research Centres
Summary:
How does a cell manage to identify and degrade the diverse types of defective proteins and thus protect the body against serious diseases? Researchers have found a crucial piece in this puzzle. In an enzyme complex that plays a critical role in the quality control of proteins, they discovered a scaffold regulating the identification and disposal of various defectively produced proteins.

How does a cell manage to identify and degrade the diverse types of defective proteins and thus protect the body against serious diseases? The researchers Sabine C. Horn, Professor Thomas Sommer, Professor Udo Heinemann and Dr. Ernst Jarosch of the Max Delbrόck Center for Molecular Medicine (MDC) Berlin-Buch, Germany, have now found a crucial piece in this puzzle.

In an enzyme complex that plays a critical role in the quality control of proteins, they discovered a scaffold regulating the identification and disposal of various defectively produced proteins.

Proteins are the building materials and the machinery of life. They are found by the thousands in a cell and carry out vital tasks in the organism.

The production site of many of the proteins is located in a cell organelle called the endoplasmic reticulum (ER). Here the proteins are produced, folded and routed to their destination.

However, during protein production errors can occur: during the process proteins can be folded in the wrong way. Older proteins may also accumulate defects due to environmental stress.

They can lose their original structure and thus fail to carry out their function and may possibly even cause damage. Diseases can develop such as Alzheimer's, Parkinson's or cystic fibrosis. Defective proteins must therefore be detected in the cell and disposed of.

Protein quality control: rejects receive a molecular tag

Proteins run through a quality control process in the cell. For the identification of defective proteins, an enzyme complex -- the HRD-ubiquitin ligase -- plays a key role.

It functions like a kind of tagging machine: If it recognizes the protein as defective, it tags it with a molecule, the protein ubiquitin, thus marking it for disposal.

Great demands are placed on the HRD-ubiquitin ligase, because proteins adapt to their cellular locations and functions and thus have quite different structures.

For instance, there are water-soluble proteins inside the cell as well as water-insoluble proteins that are situated on or in the cell membrane.

Until now it remained unclear how the enzyme complex manages to recognize and mark such different types of proteins.

Flexible scaffold makes tagging machine universally usable

The study of the MDC researchers has now shed light on this puzzle. The researchers have discovered the central and flexible scaffold of the enzyme complex, the subunit Usa1. Depending on what is required, it tethers specific modules of the complex, connecting them with each other.

When identifying and tagging soluble proteins, Usa1 establishes the contact between the subunits Der1 and Hrd1.

Furthermore, the researchers discovered that the HRD-ubiquitin ligase binds with other HRD-ubiquitin ligases to form a larger enzyme complex in order to degrade insoluble membrane proteins. This process is also regulated by the subunit Usa1.



Story Source:

The above story is based on materials provided by Helmholtz Association of German Research Centres. Note: Materials may be edited for content and length.


Journal Reference:

  1. Horn et al. Usa1 Functions as a Scaffold of the HRD-Ubiquitin Ligase. Molecular Cell, 2009; 36 (5): 782 DOI: 10.1016/j.molcel.2009.10.015

Cite This Page:

Helmholtz Association of German Research Centres. "Researchers identify scaffold regulating protein disposal." ScienceDaily. ScienceDaily, 5 January 2010. <www.sciencedaily.com/releases/2009/12/091211131611.htm>.
Helmholtz Association of German Research Centres. (2010, January 5). Researchers identify scaffold regulating protein disposal. ScienceDaily. Retrieved September 22, 2014 from www.sciencedaily.com/releases/2009/12/091211131611.htm
Helmholtz Association of German Research Centres. "Researchers identify scaffold regulating protein disposal." ScienceDaily. www.sciencedaily.com/releases/2009/12/091211131611.htm (accessed September 22, 2014).

Share This



More Plants & Animals News

Monday, September 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: San Diego Zoo Welcomes Cheetah Cubs

Raw: San Diego Zoo Welcomes Cheetah Cubs

AP (Sep. 20, 2014) — The San Diego Zoo has welcomed two Cheetah cubs to its Safari Park. The nearly three-week-old female cubs are being hand fed and are receiving around the clock care. (Sept. 20) Video provided by AP
Powered by NewsLook.com
Chocolate Museum Opens in Brussels

Chocolate Museum Opens in Brussels

AFP (Sep. 19, 2014) — Considered a "national heritage" in Belgium, chocolate now has a new museum in Brussels. In a former chocolate factory, visitors to the permanent exhibition spaces, workshops and tastings can discover derivatives of the cocoa bean. Duration: 01:00 Video provided by AFP
Powered by NewsLook.com
Could Grief Affect The Immune Systems Of Senior Citizens?

Could Grief Affect The Immune Systems Of Senior Citizens?

Newsy (Sep. 19, 2014) — The study found elderly people are much more likely to become susceptible to infection than younger adults going though a similar situation. Video provided by Newsy
Powered by NewsLook.com
Jury Delivers Verdict in Salmonella Trial

Jury Delivers Verdict in Salmonella Trial

AP (Sep. 19, 2014) — A federal jury has convicted three people in connection with an outbreak of salmonella poisoning five years ago that sickened hundreds of people and was linked to a number of deaths. (Sept. 19) Video provided by AP
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