Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Read, delete and grow

15.08.2011
Plants switch off growth signals by targeting ‘used’ receptor molecules for destruction

Plants coordinate growth using hormones called brassinosteroids (BR), and defects in the associated signaling pathway can result in profoundly stunted development. For example, researchers have identified numerous mutations within the gene encoding the BR receptor, BRI1, which yield plants with a dwarf phenotype.

The bri1-5 mutation does not directly disrupt receptor function, but nevertheless inhibits growth of thale cress, Arabidopsis thaliana, plants by somehow accelerating the rate of receptor degradation. The discovery of an additional mutation that fully counteracts this effect has now revealed valuable insights into how plants manage to keep a tight rein on growth signals.

When Guang Wu and Joanne Chory of the Salk Institute for Biological Studies, USA, identified this enigmatic sbi1 mutant, they partnered with Yuji Kamiya, a biologist at the RIKEN Plant Science Center in Yokohama. “We wanted to know the reason why sbi1 plants recover from the dwarf phenotype,” says Kamiya, “and so Wu visited my laboratory to study the mechanism of the BRI1 gene.”

An initial series of experiments provided strong evidence that the sbi1 mutant disrupts the function of a negative regulator of BRI1, which appears to act on the receptor after it has been activated by binding BR. The researchers were subsequently able to uncover the affected SBI1 gene, which encodes a member of the leucine carboxylmethyltransferase (LCMT) enzyme family.

LCMTs selectively attach methyl chemical groups onto the catalytic subunit of protein phosphatase 2A (PP2A), a multi-protein complex that deactivates a variety of receptors and other signaling proteins. Accordingly, Wu, Kamiya and colleagues found evidence that SBI1 methylates PP2A within Arabidopsis cells. This chemical modification activates the complex and alters its localization within the cell, bringing it into close proximity to BRI1 and thereby enabling it to switch off the receptor. SBI1 production is directly stimulated by BR signaling, further reinforcing this negative feedback loop.

These newly inactivated receptor molecules appear to be subsequently targeted for destruction. “We found that activated receptors that have bound BR transfer their signal to the nucleus and then get degraded, while unbound BR receptor is recycled rather than being degraded,” explains Kamiya. “By this mechanism, receptor levels are controlled in plants.”

Although similar regulatory systems are known to operate in animal cells, PP2A function is poorly understood in plants, and further investigation will be needed to determine whether this represents a general mechanism for constraining receptor signaling in Arabidopsis and other species.

The corresponding author for this highlight is based at the Growth Regulation Research Group, RIKEN Plant Science Center

Reference:
Wu, G., Wang, X., Li, X., Kamiya, Y., Otegui, M.S. & Chory, J. Methylation of a phosphatase specifies dephosphorylation and degradation of activated brassinosteroid receptors. Science Signaling 4, ra29 (2011).

gro-pr | Research asia research news
Further information:
http://www.riken.jp
http://www.researchsea.com

Further reports about: Arabidopsis thaliana PP2A RIKEN SBI1 signaling protein

More articles from Life Sciences:

nachricht Scientists unlock ability to generate new sensory hair cells
22.02.2017 | Brigham and Women's Hospital

nachricht New insights into the information processing of motor neurons
22.02.2017 | Max Planck Florida Institute for Neuroscience

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Microhotplates for a smart gas sensor

22.02.2017 | Power and Electrical Engineering

Scientists unlock ability to generate new sensory hair cells

22.02.2017 | Life Sciences

Prediction: More gas-giants will be found orbiting Sun-like stars

22.02.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>