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: First detailed picture of a cancer-related cell enzyme in action on a chromosome unit

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 capture picture of microRNA in action

5 hours ago

Biologists at The Scripps Research Institute (TSRI) have described the atomic-level workings of "microRNA" molecules, which control the expression of genes in all animals and plants.

Blocking a fork in the road to DNA replication

7 hours ago

A team of Whitehead Institute scientists has discovered the surprising manner in which an enigmatic protein known as SUUR acts to control gene copy number during DNA replication. It's a finding that could shed new light on ...

Cell division, minus the cells

10 hours ago

(Phys.org) —The process of cell division is central to life. The last stage, when two daughter cells split from each other, has fascinated scientists since the dawn of cell biology in the Victorian era. ...

A new method simplifies the analysis of RNA structure

11 hours ago

To understand the function of an RNA molecule, similar to the better-known DNA and vital for cell metabolism, we need to know its three-dimensional structure. Unfortunately, establishing the shape of an RNA ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.