Navigation Links
New Mechanism for Nutrient Uptake Discovered

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 al l 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 concentrat ions. This is a major advance in the field of plant mineral nutrition."


Related medicine news :

1. Scientists Unveil Mechanism Behind Resistance to Severe Malaria
2. New Gene Silencing Mechanism To Prevent Cancer
3. Molecular Mechanism Of HIV Infecting The Healthy Cells Discovered.
4. Self-defense Mechanism of food borne bugs found
5. Specific Immune Mechanism against DNA viruses
6. A New Focus For The Mechanism Of Nerve Growth
7. Mechanism of Stem Cell Regulation Identified
8. Cancer-Killing Viruses Employ Multiple Mechanisms
9. Regulatory Mechanism for Tumor Suppressor Protein Identified
10. Study Identifies Mechanism Which May Help Tamoxifen Work Better
11. Genetic Mechanism Helps Explain Chronic Pain Disorders
Post Your Comments:

(Date:11/27/2015)... ... 27, 2015 , ... MPWH, the No.1 Herpes-only dating community in the world, revealed that over ... More than 3.7 billion people under the age of 50 – or 67% of ... WHO's first global estimates of HSV-1 infection . , "The data shocks us highly!" ...
(Date:11/27/2015)... DE (PRWEB) , ... November 27, 2015 , ... ... member of the well-respected Microsoft Dynamics SL User Group (MSDSLUG). Recognized as Microsoft’s ... an independent group of Microsoft Dynamics SL software users, partners, industry experts and ...
(Date:11/27/2015)... (PRWEB) , ... November 27, 2015 , ... ... failing. Secura Consultants has prided itself for not only fulfilling the needs of ... protection solutions at an affordable price and providing top-tier customer service. However, there's ...
(Date:11/27/2015)... ... ... CBD College is proud to announce that on November 20th, ... its Diagnostic Medical Sonography program. CBD College is honored to join this very short ... universities in the state of California make the cut. CBD College is officially the ...
(Date:11/27/2015)... ... ... Dr. Thomas Dunlap and Dr. Patrick Coleman , cardiologist ... Medicine at St., Joseph Health System’s Santa Rosa Memorial Hospital , co-hosted the ... ways and require time-critical intervention to avoid large area heart damage and progressive infections ...
Breaking Medicine News(10 mins):
(Date:11/26/2015)... Nov. 26, 2015 Research and Markets ... the "2016 Future Horizons and Growth Strategies ... Supplier Shares, Country Segment Forecasts, Competitive Intelligence, Emerging ... --> --> This ... the Italian therapeutic drug monitoring market, including emerging ...
(Date:11/25/2015)...  Amgen (NASDAQ: AMGN ) today announced the ... the United States (U.S.) Food and ... to Humira ® (adalimumab). Amgen believes this submission ... FDA and represents Amgen,s first BLA submission using the ... M.D., executive vice president of Research and Development at ...
(Date:11/25/2015)... Nov. 25, 2015  ARKRAY USA ... to provide evidence demonstrating the accuracy of its blood ... on Insulin Resistance, Diabetes and Cardiovascular Disease in ... the Company,s GLUCOCARD ® 01 meter and the ... requirements. The ability to accurately measure glucose levels in ...
Breaking Medicine Technology: