Featured Research

from universities, journals, and other organizations

Different evolutionary paths lead plants and animals to the same crossroads

Date:
February 7, 2011
Source:
Salk Institute
Summary:
In analyzing the molecular sensor for the plant growth hormone brassinolide, researchers discovered that although plants took an evolutionary path different from their animal cousins, they arrived at similar solutions to a common problem: How to reliably receive and process incoming signals.

Despite their divergent evolutionary history, membrane-bound kinase receptors in animals and plants rely on similar regulatory mechanisms to control their activity.
Credit: Courtesy of Yvon Jaillard, Michael Hothorn and Jamie Simon, Salk Institute for Biological Studies

In analyzing the molecular sensor for the plant growth hormone brassinolide, researchers at the Salk Institute for Biological Studies discovered that although plants took an evolutionary path different from their animal cousins, they arrived at similar solutions to a common problem: How to reliably receive and process incoming signals.

The team's findings, published in the February 1, 2011 issue of Genes and Development, revealed that so-called tyrosine phosphorylation -- used as an "on" or "off" switch and long thought to be a feature unique to animal cells -- is a mechanism conserved across the animal and plant kingdoms.

"There seem to be only so many ways to build a robust signaling system," says Howard Hughes Medical Institute investigator Joanne Chory, Ph.D., professor and director of the Plant Molecular and Cellular Biology Laboratory and holder of the Howard H. and Maryam R. Newman Chair, "and plants and animals have hit upon the same mechanisms."

As different as they may seem, both mammalian and plant cells need to be able to perceive small molecule hormones to respond to changes in the environment. While human cells draw on a wide variety of sensor molecules, including more than 800 different G-protein-coupled receptors, 48 known nuclear hormone receptors and 72 receptor kinases, plants rely mostly on the latter.

"This group of receptors is by far the largest one in plants," says postdoctoral researcher and co-first author Michael Hothorn, "but we don't know much about the activation mechanism apart from 'there's a bunch of new phosphorylations.'"

Kinases transfer phosphate groups to proteins and come in two principal flavors: They either attach the phosphate group to the amino acid tyrosine within the protein or to serine or threonine. The vast majority of receptor kinases in animals possess tyrosine kinase activity, while only a few are specific for serine-threonine.

With the exception of a small handful of dual-specificity kinases, all plant receptor kinases have been pegged as serine-threonine kinases. One of few known outliers is the receptor for brassinolide, a key element of plants' response to light. "Binding of brassinolide to its receptor allows plants to adjust growth when they need to outcompete their neighbors to reach more light or water," explains postdoctoral researcher and co-first author Yvon Jaillais. "But at the same time the receptor needs to be tightly regulated so plants don't waste their resources when they don't have to."

The brassinolide receptor BRI1 is kept in a relatively inactive state by its intracellular tail and a small inhibitory protein known as BKI1. Based on earlier studies in Chory's lab, the Salk researchers knew that autophosphorylation of the receptor was necessary, but what triggered the release of the inhibitory protein remained unclear.

In an effort to understand the activation mechanism, the Salk researchers discovered that BKI1 acts through two evolutionarily conserved motifs: a 20-amino- acid sequence that binds the receptor kinase domain and a lysine-arginine-rich motif that anchors the inhibitory peptide to the plasma membrane. Phosphorylation of a key tyrosine within the membrane-targeting motif releases BKI1 from the membrane, relieving kinase inhibition and allowing the formation of an active signaling complex.

The phosphorylation of BKI1 is not only the first documented example of tyrosine transphosphorylation in plants, the underlying principle also closely resembles the mechanism used by bona fide receptor tyrosine kinases to regulate their activity. "Plant and animal receptor kinases evolved independently, yet their activation relies on similar mechanisms," says Chory.

By defining common features in plant and animal receptor signaling pathways, the Salk researchers hope to learn more about what the requirements for a robust signaling system are. Although plants don't encode canonical tyrosine kinases in their genomes, tyrosine phosphorylation will emerge as an important topic in plant signaling, predicts Hothorn.

Researchers who also contributed to the work include Yousseff Belkhadir and Tsegaye Dabi in the Plant Biology Laboratory at the Salk Institute, as well as Zachary L. Nimchuk and Elliot Meyerowitz in the Division of Biology at the California Institute of Technology in Pasadena, California.

The work was funded in part by the Howard Hughes Medical Institute, the National Institutes of Health, the National Science Foundation, the European Molecular Biology Organization, the International Human Frontier Science Program Organization, the Life Sciences Research Foundation, and the Marc and Eva Stern Foundation.


Story Source:

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


Journal Reference:

  1. Y. Jaillais, M. Hothorn, Y. Belkhadir, T. Dabi, Z. L. Nimchuk, E. M. Meyerowitz, J. Chory. Tyrosine phosphorylation controls brassinosteroid receptor activation by triggering membrane release of its kinase inhibitor. Genes & Development, 2011; 25 (3): 232 DOI: 10.1101/gad.2001911

Cite This Page:

Salk Institute. "Different evolutionary paths lead plants and animals to the same crossroads." ScienceDaily. ScienceDaily, 7 February 2011. <www.sciencedaily.com/releases/2011/01/110131172111.htm>.
Salk Institute. (2011, February 7). Different evolutionary paths lead plants and animals to the same crossroads. ScienceDaily. Retrieved October 21, 2014 from www.sciencedaily.com/releases/2011/01/110131172111.htm
Salk Institute. "Different evolutionary paths lead plants and animals to the same crossroads." ScienceDaily. www.sciencedaily.com/releases/2011/01/110131172111.htm (accessed October 21, 2014).

Share This



More Plants & Animals News

Tuesday, October 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Cadaver Dogs Aid Search for More Victims of Suspected Indiana Serial Killer

Cadaver Dogs Aid Search for More Victims of Suspected Indiana Serial Killer

Reuters - US Online Video (Oct. 21, 2014) Police in Gary, Indiana are using cadaver dogs to search for more victims after a suspected serial killer confessed to killing at least seven women. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
White Lion Cubs Unveiled to the Public

White Lion Cubs Unveiled to the Public

Reuters - Light News Video Online (Oct. 21, 2014) Visitors to Belgrade zoo meet a pair of three-week-old lion cubs for the first time. Tara Cleary reports. Video provided by Reuters
Powered by NewsLook.com
'Cadaver Dog' Sniffs out Human Remains

'Cadaver Dog' Sniffs out Human Remains

AP (Oct. 21, 2014) Where's a body buried? Buster's nose can often tell you. He's a cadaver dog, specially trained to find human remains and increasingly being used by law enforcement and accepted in courts. These dogs are helping solve even decades-old mysteries. (Oct. 21) Video provided by AP
Powered by NewsLook.com
White Lion Cubs Born in Belgrade Zoo

White Lion Cubs Born in Belgrade Zoo

AFP (Oct. 20, 2014) Two white lion cubs, an extremely rare subspecies of the African lion, were recently born at Belgrade Zoo. They are being bottle fed by zoo keepers after they were rejected by their mother after birth. Duration: 00:42 Video provided by AFP
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:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

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