Navigation Links
MDC researchers identify a scaffold regulating protein disposal
Date:12/11/2009

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 Delbrck 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. (Molecular Cell, doi: 10.1016/j.molcel200910.015)*.

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.


'/>"/>

Contact: Barbara Bachtler
bachtler@mdc-berlin.de
49-309-406-3896
Helmholtz Association of German Research Centres
Source:Eurekalert

Related biology news :

1. UCLA researchers engineer bacteria to turn carbon dioxide into liquid fuel
2. Berkeley Lab researchers participate in Homeland Security study of subway airflow
3. Hebrew University, American researchers show trigger to stem cell differentiation
4. Carnegie Mellon researchers receive grant
5. Researchers finds hidden sensory system in the skin
6. Researchers demonstrate nanoscale X-ray imaging of bacterial cells
7. Texas AgriLife researchers helping
8. Stopping MRSA before it becomes dangerous is possible, Sandia/UNM researchers find
9. VAI researchers find long awaited key to creating drought resistant crops
10. UGA researchers lead team in discovery involving devastating freshwater fish parasite, Ich
11. Nervy research: Researchers take initial look at ion channels in a model system
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:1/25/2016)... , Jan. 25, 2016  Glencoe Software, the ... pharma and publication industries, will provide the data management ... Centre (NPSC). ... Phenotypic analysis measures ... whole organisms, allowing comparisons between states such as health ...
(Date:1/20/2016)... 2016   MedNet Solutions , an innovative SaaS-based ... clinical research, is pleased to announce the attainment of ... the result of the company,s laser focus on (and ... , it,s comprehensive, easy-to-use and highly affordable cloud-based technology ... Key MedNet growth achievements in 2015 include: ...
(Date:1/13/2016)... January 13, 2016 ... addition of the  "India Biometrics Authentication ... Forecast (2015-2020)"  report to their ... has announced the addition of the  ... - Estimation & Forecast (2015-2020)" ...
Breaking Biology News(10 mins):
(Date:2/8/2016)... ... 2016 , ... Franz Inc. , an early innovator ... announced the availability of AllegroGraph 6, the leading Semantic Graph Database with certification ... Program (CCPT). AllegroGraph is the first Semantic Graph Database to be certified ...
(Date:2/8/2016)... England , February 8, 2016 ... Ltd ("Atlas Genetics" or the "Company"), the ultra-rapid Point-Of-Care (POC) ... to CE Mark its Chlamydia trachomatis (CT) test to be ... of the IVD Directive (98/79/EC), the CT test is now ... --> --> The launch of the io® ...
(Date:2/5/2016)... Feb. 5, 2016  In the pharmaceutical industry the ... host of launch activities including the identification and engagement ... activity is especially high in the oncology therapeutic area ... Practices and the Role of Medical Affairs in Oncology ... on oncology therapies find better ways to utilize medical ...
(Date:2/4/2016)... ... February 04, 2016 , ... Morf ... today announced an interactive FDA compliance training course, Writing Effective ... Professional Society) accredited interactive course on Morf Playbook—now conveniently available on smartphones and ...
Breaking Biology Technology: