Nav: Home

Dynamics of crucial protein 'switch' revealed

May 17, 2011

Researchers at the University of Texas Medical Branch at Galveston and the University of California-San Diego School of Medicine have published a study that offers a new understanding of a protein critical to physiological processes involved in major diseases such as diabetes and cancer. This work could help scientists design drugs to battle these disorders.

The article was deemed a "Paper of the Week" by and will be on the cover of the Journal of Biological Chemistry. It is scheduled for publication May 20 and now available online.

"This study applied a powerful protein structural analysis approach to investigate how a chemical signal called cAMP turns on one of its protein switches, Epac2," said principal investigator Xiaodong Cheng, professor in the Department of Pharmacology and Toxicology and member of the Sealy Center for Structural Biology and Molecular Biophysics at UTMB.

The cAMP molecule controls many physiological processes, ranging from learning and memory in the brain and contractility and relaxation in the heart to insulin secretion in the pancreas. cAMP exerts its action in cells by binding to and switching on specific receptor proteins, which, when activated by cAMP, turn on additional signaling pathways.

Errors in cell signaling are responsible for diseases such as diabetes, cancer and heart failure. Understanding cAMP-mediated cell signaling, in which Epac2 is a major player, likely will facilitate the development of new therapeutic strategies specifically targeting the cAMP-Epac2 signaling components, according to the researchers.

The project involved an ongoing collaboration between Cheng's research group at UTMB, experts in the study of cAMP signaling, and UCSD professor of medicine Virgil Woods Jr. and colleagues at UCSD, pioneers in the development and application of hydrogen/deuterium exchange mass spectrometry (DXMS) technology. Compared with other protein-analysis techniques, DXMS is especially good at studying the structural motion of proteins.

Using this novel approach, the investigators were able to reveal, in fine detail, that cAMP interacts with its two known binding sites on Epac2 in a sequential fashion and that binding of cAMP changes the shape of the protein in a very specific way - switching on its activity by exposing further signaling interaction sites on Epac2.

"DXMS analysis has proved to be an amazingly powerful approach, alone or in combination with other techniques, in figuring out how proteins work as molecular machines, changing their shapes - or morphing - in the normal course of their function," said Woods. "This will be of great use in the identification and development of therapeutic drugs that target these protein motions."

-end-

Collaborators include Tamara Tsalkova and Fang Mei of the UTMB Department of Pharmacology and Toxicology; Mark A. White, associate professor in the UTMB Department of Biochemistry and Molecular Biology; and Dr. Sheng Li, Dr. Tong Liu and Daphne Wang of the UCSD Department of Medicine and Biomedical Sciences Graduate Program.

The study was funded by the National Institutes of Health and the John Sealy Memorial Endowment Fund for Biomedical Research. Based on its success at applying DXMS to the analysis of a number of important proteins, exemplified by this study with UTMB researchers, UCSD recently was awarded a generous NIH grant to implement "next-generation" advanced DXMS analysis for the benefit of scientists throughout the United States.

Photographs: http://bit.ly/kxhNeJ, http://bit.ly/jCzZSr, http://bit.ly/lEEU5d

University of Texas Medical Branch at Galveston
The role of vitamin A in diabetes
There has been no known link between diabetes and vitamin A -- until now.
Can continuous glucose monitoring improve diabetes control in patients with type 1 diabetes who inject insulin
Two studies in the Jan. 24/31 issue of JAMA find that use of a sensor implanted under the skin that continuously monitors glucose levels resulted in improved levels in patients with type 1 diabetes who inject insulin multiple times a day, compared to conventional treatment.
Complications of type 2 diabetes affect quality of life, care can lead to diabetes burnout
T2D Lifestyle, a national survey by Health Union of more than 400 individuals experiencing type 2 diabetes (T2D), reveals that patients not only struggle with commonly understood complications, but also numerous lesser known ones that people do not associate with diabetes.
Type 2 diabetes and obesity -- what do we really know?
Social and economic factors have led to a dramatic rise in type 2 diabetes and obesity around the world.
A better way to predict diabetes
An international team of researchers has discovered a simple, accurate new way to predict which women with gestational diabetes will develop type 2 diabetes after delivery.
The Lancet Diabetes & Endocrinology: Older Americans with diabetes living longer without disability, US study shows
Older Americans with diabetes born in the 1940s are living longer and with less disability performing day to day tasks than those born 10 years earlier, according to new research published in The Lancet Diabetes & Endocrinology journal.
Reverse your diabetes -- and you can stay diabetes-free long-term
A new study from Newcastle University, UK, has shown that people who reverse their diabetes and then keep their weight down remain free of diabetes.
New cause of diabetes
Although insulin-producing cells are found in the endocrine tissue of the pancreas, a new mouse study suggests that abnormalities in the exocrine tissue could cause cell non-autonomous effects that promotes diabetes-like symptoms.
The Lancet Diabetes & Endocrinology: Reducing sugar content in sugar-sweetened drinks by 40 percent over 5 years could prevent 1.5 million cases of overweight and obesity in the UK and 300,000 cases of diabetes
A new study published in The Lancet Diabetes & Endocrinology journal suggests that reducing sugar content in sugar sweetened drinks (including fruit juices) in the UK by 40 percent over five years, without replacing them with any artificial sweeteners, could prevent 500,000 cases of overweight and 1 million cases of obesity, in turn preventing around 300,000 cases of type 2 diabetes, over two decades.
Breastfeeding lowers risk of type 2 diabetes following gestational diabetes
Women with gestational diabetes who consistently and continuously breastfeed from the time of giving birth are half as likely to develop type 2 diabetes within two years after delivery, according to a study from Kaiser Permanente published today in Annals of Internal Medicine.

Best Science Podcasts 2017

We have hand picked the best science podcasts for 2017. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.

Now Playing: Radiolab

Truth Trolls
Today, a third story of folks relentlessly searching for the truth. But this time, the truth seekers are an unlikely bunch... internet trolls.


Now Playing: TED Radio Hour

Rethinking School
For most of modern history, humans have placed smaller humans in institutions called schools. But what parts of this model still work? And what must change? This hour, TED speakers rethink education.TED speakers include teacher Tyler DeWitt, social entrepreneur Sal Khan, international education expert Andreas Schleicher, and educator Linda Cliatt-Wayman.