Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Sugar coupled to protein causes kidneys to save water

10.10.2003



Giel Hendriks discovered that the linking of sugars to the protein aquaporin-2 (AQP2) is necessary for the transport of water channels to the cell surfaces in the kidneys. If the protein is not linked to a sugar, it still forms functional water channels. However, these channels no longer end up at the cell surface where they need to do their work.

Kidneys extract water containing dissolved waste substances from the blood. Each day human kidneys produced about 180 litres of this so-called pro-urine. The excretion of all of this fluid would rapidly result in dehydration and eventual death. Therefore with the help of the water channels, the body returns about 99% of this water from the pro-urine to the kidney tissue. As a result of this a person only loses about 1.5 litres of urine per day.


The protein aquaporin-2 regulates a significant part of this water reuse. This protein forms water channels. These are transported from small storage vesicles to the cell surface, where they can collect the water and return it to the kidney tissue.

Mutations in AQP2 give rise to the disease nephrogenic diabetes insipidus (NDI). Patients with this disease lose 15 to 20 litres of urine per day. Knowing how AQP2 is transported to the cell surface and how it works there, is a prerequisite for developing a treatment for this disease.

In addition to the effect of sugars, Hendriks also studied the role of the small signalling protein ubiquitin in the functioning of AQP2. Ubiquitin ensures the breakdown of proteins and is important for quality control during the production of new proteins. Hendriks isolated AQP2 proteins to which a single ubiquitin was bound. Separating the proteins on the cell surface from those inside the cell revealed that only AQP2 with a single ubiquitin is located on the cell surface. The role of this coupling in the functioning of the protein will be investigated in a follow-up study by the Utrecht group.

Finally, the researchers isolated a new protein from a mouse kidney, AQP2-BP that directly binds to AQP2. Up until now no proteins capable of binding to AQP2 were known. By inserting both proteins in kidney cells, Hendriks discovered that AQP2-BP is important for the production of the useful protein AQP2.

Sonja Jacobs | alfa
Further information:
http://www.nwo.nl

More articles from Health and Medicine:

nachricht Vanishing capillaries
23.03.2017 | Technische Universität München

nachricht How prenatal maternal infections may affect genetic factors in Autism spectrum disorder
22.03.2017 | University of California - San Diego

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

When Air is in Short Supply - Shedding light on plant stress reactions when oxygen runs short

23.03.2017 | Life Sciences

Researchers use light to remotely control curvature of plastics

23.03.2017 | Power and Electrical Engineering

Sea ice extent sinks to record lows at both poles

23.03.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>