New component of a plant steroid-activated pathway discovered

Aug 18, 2011

Plant biologists have been working for years to nail down the series of chemical signals that one class of plant hormones, called brassinosteroids, send from a protein on the surface of a plant cell to the cell's nucleus. New research from Carnegie scientists Tae-Wuk Kim and Zhiyong Wang, with contributions from the University of California San Francisco, isolated another link in this chain. Fully understanding the brassinosteroid pathway could help scientists better understand plant growth and help improve food and energy crop production.

Brassinosteroids are found throughout the plant kingdom and regulate many aspects of growth and development, as well as resistance to external stresses. that are deficient in brassinosteroids show defects at many phases of the plant life cycle including reduced seed germination, irregular growth in the absence of light, dwarfism, and sterility.

The series of proteins involved in a plant cell detecting the presence of brassinosteroids and using this information to respond to the plant's environment is one of the best-studied aspects of plant cellular physiology and biochemistry. Previous research had identified a pathway of that starts when a brassinosteroid binds to a receptor on the surface of a plant cell and activates a cascade of activity that consists of adding and removing phosphates from a series of proteins.

The research team was able to identify a new aspect of this pathway, a protein called Constitutive Differential Growth1, or CDG1. Their work will be published in Molecular Cell on August 19.

Using an extensive array of research techniques, they determined that when activated by the brassinosteroid receptor, CDG1 adds a phosphate to another protein called BSU1. It was already known that the BSU1 protein in turns deactivates a third protein called BIN2. When BIN2 is active it inhibits two other proteins called BZR1 and BZR2, which are part of a special class called . When they are inactive, they are unable to enter the plant cell's nucleus. But once BIN2 is deactivated by BSU1, they are able to bind directly to DNA molecules inside the nucleus and promote a wide variety of gene activity.

"Together with our previous work, these results provide the detailed mechanisms of brassinosteroid signaling," Wang said. "Because this system of brassinosteroid-activated proteins is one of the best-understood chemical pathways in plant physiology, these results could help scientists understand many other plant cell systems."

Explore further: Researchers successfully clone adult human stem cells

Provided by Carnegie Institution

not rated yet
add to favorites email to friend print save as pdf

Related Stories

Nailing down a crucial plant signaling system

Jan 23, 2011

Plant biologists have discovered the last major element of the series of chemical signals that one class of plant hormones, called brassinosteroids, send from a protein on the surface of a plant cell to the cell's nucleus. ...

Mastermind steroid found in plants

Nov 15, 2010

Scientists have known for some time how important plant steroids called brassinosteroids are for regulating plant growth and development. But until now, they did not know how extensive their reach is. Now researchers, including ...

Unlocking the secrets of a plant's light sensitivity

Dec 13, 2010

(PhysOrg.com) -- Plants are very sensitive to light conditions because light is their source of energy and also a signal that activates the special photoreceptors that regulate growth, metabolism, and physiological ...

Plants on Steroids: Key Missing Link Discovered

Sep 08, 2009

(PhysOrg.com) -- Researchers at the Carnegie Institution's Department of Plant Biology have discovered a key missing link in the so-called signaling pathway for plant steroid hormones (brassinosteroids). Many important signaling ...

Antagonistic genes control rice growth

Dec 15, 2009

Scientists at the Carnegie Institution, with colleagues, have found that a plant steroid prompts two genes to battle each other—one suppresses the other to ensure that leaves grow normally in rice and the ...

In plants, small changes make big impact

Oct 07, 2010

(PhysOrg.com) -- You can’t see them or feel them, but right now countless biochemical interactions in your body affect your life in countless ways. These interactions are important because if they go ...

Recommended for you

Researchers successfully clone adult human stem cells

Apr 18, 2014

(Phys.org) —An international team of researchers, led by Robert Lanza, of Advanced Cell Technology, has announced that they have performed the first successful cloning of adult human skin cells into stem ...

Researchers develop new model of cellular movement

Apr 18, 2014

(Phys.org) —Cell movement plays an important role in a host of biological functions from embryonic development to repairing wounded tissue. It also enables cancer cells to break free from their sites of ...

For resetting circadian rhythms, neural cooperation is key

Apr 17, 2014

Fruit flies are pretty predictable when it comes to scheduling their days, with peaks of activity at dawn and dusk and rest times in between. Now, researchers reporting in the Cell Press journal Cell Reports on April 17th h ...

User comments : 0

More news stories

Researchers successfully clone adult human stem cells

(Phys.org) —An international team of researchers, led by Robert Lanza, of Advanced Cell Technology, has announced that they have performed the first successful cloning of adult human skin cells into stem ...

Airbnb rental site raises $450 mn

Online lodging listings website Airbnb inked a $450 million funding deal with investors led by TPG, a source close to the matter said Friday.

Health care site flagged in Heartbleed review

People with accounts on the enrollment website for President Barack Obama's signature health care law are being told to change their passwords following an administration-wide review of the government's vulnerability to the ...