Featured Research

from universities, journals, and other organizations

New Mechanism For Nutrient Uptake Discovered

Date:
February 12, 2007
Source:
Carnegie Institution
Summary:
Biologists at the Carnegie Institution's Department of Plant Biology have discovered a new way that plant cells govern nutrient regulation--neighboring pore-like structures at the cell's surface physically interact to control the uptake of a vital nutrient, nitrogen. It is the first time scientists have found that the interaction of neighboring molecules is essential to this regulation. The discovery has widespread potential -- from understanding human diseases, such as kidney function, to engineering better crops.

Biologists at the Carnegie Institution's Department of Plant Biology have discovered a new way that plant cells govern nutrient regulation--neighboring pore-like structures at the cell's surface physically interact to control the uptake of a vital nutrient, nitrogen. It is the first time scientists have found that the interaction of neighboring molecules is essential to this regulation. Since plants, animals, bacteria, and fungi all share similar genes for this activity, the scientists believe that the same feature could occur across species. The discovery, published in the February 11th on-line edition of Nature, has widespread potential--from understanding human diseases, such as kidney function, to engineering better crops.

"Every cell in every organism has a system for bringing in nutrition and expelling waste," explained lead author Dominique Loqué. "Some are through pore-like protein structures called transporters, which reside at the surface of the cell's outer membrane. Each pore is capable of transporting nutrients individually, so we were really surprised to find that the pores simply can't act without stimulation from their neighbors."

In earlier research the Carnegie scientists, with colleagues, identified the genes responsible for initiating nitrogen uptake in plants. That identification has helped other researchers find the relatives of these genes in a variety of species from bacteria to humans. In this study, the scientists wanted to identify how ammonium transport is regulated.

Plants import nitrogen in the form of ammonium from the soil. The researchers found that the end portion, or so-called C-terminus, of the protein Arabidopsis ammonium transporter AtAMT1;1, located at the surface of the cell membrane, acts as a switch.

"The terminus is an arm-like feature that physically grabs a neighboring short-chain molecule, binds with it, and changes the shape of itself and its neighbor thereby activating all the pores in the complex," continued Loqué. "The pores can't function without this physical stimulation."

"The rapid chain-reaction among the different pores allows the system to shut down extremely fast and can even memorize previous exposures," noted co-author Wolf Frommer. "Imagine a large animal marking its territory. A sudden flow of ammonia could be toxic to the plant. If it weren't for a rapid-fire shutdown plants could die. The conservation of this feature in the related transporters in bacteria, fungi, plants, and animals suggests that an ancient organism, which was a precursor to all known organisms on Earth, had developed this feature because there was much more ammonia on the early Earth. The ubiquitous presence of this structure in all of the known ammonium transporters suggests that the regulation is still necessary today for all of these organisms--cyanobacteria in the ocean, fungi that grow on grapes and make our wine, plants that provide our food--and even in our kidneys, which excrete nitrogen. We also suspect other different types of transporters will be discovered to work in this way."

The scientists don't yet know what triggers the rapid shut-off. They think it might be a very common regulatory event called phosphorylation, where a phosphate molecule is introduced to another molecule, changing the latter, and preparing it for a chemical reaction. They have found a site for phosphorylation and are looking at this possibility further.

A leading expert in transporters, Professor Dale Sanders, head of the biology department at the University of York in the U.K. commenting on the work said: "Loqué, Frommer and co-workers have demonstrated very beautifully how plant ammonium transporters are controlled. A switch domain in the protein facilitates rapid and sensitive control of ammonium transport to preclude over-accumulation of an ion that is beneficial at low concentrations, but potentially toxic at high concentrations. This is a major advance in the field of plant mineral nutrition."


Story Source:

The above story is based on materials provided by Carnegie Institution. Note: Materials may be edited for content and length.


Cite This Page:

Carnegie Institution. "New Mechanism For Nutrient Uptake Discovered." ScienceDaily. ScienceDaily, 12 February 2007. <www.sciencedaily.com/releases/2007/02/070211200654.htm>.
Carnegie Institution. (2007, February 12). New Mechanism For Nutrient Uptake Discovered. ScienceDaily. Retrieved August 29, 2014 from www.sciencedaily.com/releases/2007/02/070211200654.htm
Carnegie Institution. "New Mechanism For Nutrient Uptake Discovered." ScienceDaily. www.sciencedaily.com/releases/2007/02/070211200654.htm (accessed August 29, 2014).

Share This




More Plants & Animals News

Friday, August 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Killer Amoeba Found in Louisiana Water System

Killer Amoeba Found in Louisiana Water System

AP (Aug. 28, 2014) — State health officials say testing has confirmed the presence of a killer amoeba in a water system serving three St. John the Baptist Parish towns. (Aug. 28) Video provided by AP
Powered by NewsLook.com
Raw: Australian Sheep Gets Long Overdue Haircut

Raw: Australian Sheep Gets Long Overdue Haircut

AP (Aug. 28, 2014) — Hoping to break the record for world's wooliest, Shaun the sheep came up 10 pounds shy with his fleece weighing over 50 pounds after being shorn for the first time in years. (Aug. 28) Video provided by AP
Powered by NewsLook.com
Minds Blown: Scientists Develop Fish That Walk On Land

Minds Blown: Scientists Develop Fish That Walk On Land

Newsy (Aug. 28, 2014) — Canadian scientists looking into the very first land animals took a fish out of water and forced it to walk. Video provided by Newsy
Powered by NewsLook.com
Fake Dogs Scare Real Geese from Wis. Park

Fake Dogs Scare Real Geese from Wis. Park

AP (Aug. 28, 2014) — Parks officials in Stevens Point, Wisconsin had a fowl problem. Canadian Geese were making a mess of a park, so officials enlisted cardboard versions of man's best friend. (Aug. 28) 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