Featured Research

from universities, journals, and other organizations

Humans And Plants Share Common Regulatory Pathway

Date:
April 12, 2007
Source:
Scripps Research Institute
Summary:
In findings that some might find reminiscent of science fiction, scientists at the Scripps Research Institute have shown for the first time that humans and plants share a common pathogen recognition pathway as part of their innate immune systems. The data could help shed fresh light on how pathogen recognition proteins function and the role they play in certain chronic inflammatory diseases.

In findings that some might find reminiscent of science fiction, scientists at the Scripps Research Institute have shown for the first time that humans and plants share a common pathogen recognition pathway as part of their innate immune systems. The data could help shed fresh light on how pathogen recognition proteins function and the role they play in certain chronic inflammatory diseases.

The study provides new evidence that Nod1, a member of the Nod-like Receptor (NLR) protein family, is activated by the protein SGT1, which also activates Resistance (R) proteins in plants; R proteins protect plants from various pathogens. The study also confirms structural similarities between the Nod1 protein, which plays a pivotal role in the innate immune system's recognition and response to bacterial infection and members of the R protein family.

"There has been a great deal of speculation that R proteins and Nod1 are related, but our study provides the first direct link between plants and humans," said Richard Ulevitch, the Scripps Research scientist whose laboratory conducted the study. "Plants have Nod-like receptors and similar immune responses to bacteria and other pathogens-the R proteins evolved to counteract these pathogenic effects. Our study provides a new perspective on the Nod1 pathway in mammalian cells as well as the value of drawing on plant studies of R protein pathways to better understand the pathogen recognition functions of these proteins."

The Nod proteins recognize invasive bacteria, specifically distinct substructures found in Gram-negative and Gram-positive organisms. Once activated, Nod1 produces a number of responses that include activation of intracellular signaling pathways, cytokine production and apoptosis or programmed cell death. Despite the fact that various models of Nod1 activation have been described, little has been known about other proteins that might affect the protein's activation. In contrast, a number of additional proteins have been linked to the activation pathways of the R protein in plants.

"The NLR family has clear links to human disease," Ulevitch said. "Out of the more than 20 proteins in the NLR family, several mutations are linked to diseases that involve chronic inflammation or autoimmune consequences. Up to now, there has been a limited understanding of the regulatory pathways of Nod1. By identifying SGT1 as a positive regulatory protein, our study offers new insights into the entire family."

SGT1 is a protein found in yeasts, plants, and mammals in both the nucleus and the cytosol. It functions in several biological processes through interaction with different multi-protein complexes. A large body of evidence also suggests that the protein plays a role in regulating pathogen resistance in plants. Various genetic studies have identified SGT1 as a crucial component for pathogen resistance in plants through regulation of expression and activities of some R proteins

Although there is a significant genetic crossover between plants and mammals, very little is known about this common human-plant regulatory pathway. Ulevitch speculated that certain protein regulatory structures might exist in both plants and humans simply because they do the same thing in much the same way.

"In reality," he said, "there are only so many ways to accomplish related biological responses."

The study also showed that a heat shock protein, HSP90, helped stabilize Nod1.

"Inhibiting HSP90 resulted in a significant reduction of Nod1 protein levels," Ulevitch said. "That clearly suggests that this protein plays a key role in stabilizing Nod1 and protecting it from degradation. In contrast, turning off SGT1 did not alter levels of Nod1."

In an earlier study, Ulevitch's laboratory reported that Nod1 also interacted with the COP9 complex, a multiprotein complex that is known to play a role in a number of development pathways in plants and that has a mammalian counterpart. This interaction, Ulevitch noted, provides a second link between Nod1 and plant R protein pathways.

"The association of Nod1 with SGT1 and the COP9 complex suggests that one possible role of SGT1 could be to target resistance-regulating proteins for degradation," he added. "In this hypothesis, the target protein would be a negative regulator of immune responses."

Future studies, Ulevitch said, will focus on the extensive literature that exists describing the R protein dependent immunity in plants to better understand human NLR pathways, especially those dependent on Nod1.

The study was supported by the National Institutes of Health and Novartis. The study was published in an advance online edition of the Proceedings of the National Academy of Sciences during the week of April 9, 2007.

Other authors of the study, "SGT1 Is Essential for NOD1 Activation," are Jean da Silva Correia, Yvonne Miranda, and Nikki Leonard.


Story Source:

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


Cite This Page:

Scripps Research Institute. "Humans And Plants Share Common Regulatory Pathway." ScienceDaily. ScienceDaily, 12 April 2007. <www.sciencedaily.com/releases/2007/04/070409181653.htm>.
Scripps Research Institute. (2007, April 12). Humans And Plants Share Common Regulatory Pathway. ScienceDaily. Retrieved July 28, 2014 from www.sciencedaily.com/releases/2007/04/070409181653.htm
Scripps Research Institute. "Humans And Plants Share Common Regulatory Pathway." ScienceDaily. www.sciencedaily.com/releases/2007/04/070409181653.htm (accessed July 28, 2014).

Share This




More Plants & Animals News

Monday, July 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Sea Turtle Hatchlings Emerge from Nest

Raw: Sea Turtle Hatchlings Emerge from Nest

AP (July 27, 2014) A live-streaming webcam catches loggerhead sea turtle hatchlings emerging from a nest in the Florida Keys. (July 27) Video provided by AP
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
What's To Blame For Worst Ebola Outbreak In History?

What's To Blame For Worst Ebola Outbreak In History?

Newsy (July 27, 2014) A U.S. doctor has tested positive for the deadly Ebola virus, as the worst-ever outbreak continues to grow. Video provided by Newsy
Powered by NewsLook.com
The New York Times Backs Pot Legalization

The New York Times Backs Pot Legalization

Newsy (July 27, 2014) The New York Times has officially endorsed the legalization of marijuana, but why now, and to what end? 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