Featured Research

from universities, journals, and other organizations

Sugar Coupled To Protein Causes Kidneys To Save Water

Date:
October 13, 2003
Source:
Netherlands Organization For Scientific Research
Summary:
Several new mechanisms that are important for the production and transport of water channels to the cell surface of kidneys have been identified by a Dutch researcher. The water channels ensure that water in the body is reused. If these fail to work properly, you urinate too much and dehydrate.

Several new mechanisms that are important for the production and transport of water channels to the cell surface of kidneys have been identified by a Dutch researcher. The water channels ensure that water in the body is reused. If these fail to work properly, you urinate too much and dehydrate. The research was a collaborative project between the University Medical Centre Utrecht and the University Medical Centre Nijmegen.

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.

###

The research was funded by the Netherlands Organisation for Scientific Research.


Story Source:

The above story is based on materials provided by Netherlands Organization For Scientific Research. Note: Materials may be edited for content and length.


Cite This Page:

Netherlands Organization For Scientific Research. "Sugar Coupled To Protein Causes Kidneys To Save Water." ScienceDaily. ScienceDaily, 13 October 2003. <www.sciencedaily.com/releases/2003/10/031013000841.htm>.
Netherlands Organization For Scientific Research. (2003, October 13). Sugar Coupled To Protein Causes Kidneys To Save Water. ScienceDaily. Retrieved July 28, 2014 from www.sciencedaily.com/releases/2003/10/031013000841.htm
Netherlands Organization For Scientific Research. "Sugar Coupled To Protein Causes Kidneys To Save Water." ScienceDaily. www.sciencedaily.com/releases/2003/10/031013000841.htm (accessed July 28, 2014).

Share This




More Health & Medicine News

Monday, July 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Traditional African Dishes Teach Healthy Eating

Traditional African Dishes Teach Healthy Eating

AP (July 28, 2014) Classes are being offered nationwide to encourage African Americans to learn about cooking fresh foods based on traditional African cuisine. The program is trying to combat obesity, heart disease and other ailments often linked to diet. (July 28) Video provided by AP
Powered by NewsLook.com
West Africa Gripped by Deadly Ebola Outbreak

West Africa Gripped by Deadly Ebola Outbreak

AFP (July 28, 2014) The worst-ever outbreak of the deadly Ebola epidemic grips west Africa, killing hundreds. Duration: 00:48 Video provided by AFP
Powered by NewsLook.com
Trees Could Save More Than 850 Lives Each Year

Trees Could Save More Than 850 Lives Each Year

Newsy (July 27, 2014) A national study conducted by the USDA Forest Service found that trees collectively save more than 850 lives on an annual basis. Video provided by Newsy
Powered by NewsLook.com
Google's Next Frontier: The Human Body

Google's Next Frontier: The Human Body

Newsy (July 27, 2014) Google is collecting genetic and molecular information to paint a picture of the perfectly healthy human. 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