These insights not only set up the researchers for more advanced studies on phosphohistidine and its potential role in cancer, but will also enable scientists to manipulate the shape and atomic makeup of the antibodies’ binding sites in order to design ever more efficient antibodies in the future. The study was published in the Proceedings of the National Academy of Sciences on February 5.

“We are excited that these new antibody structures reveal novel principles of antigen binding. Now we can redesign these antibodies and engineer their properties to make them more efficient,” says Tony Hunter, Renato Dulbecco Chair and American Cancer Society Professor at Salk and the paper’s senior author. “This work may also provide other scientists with phosphohistidine antibodies that better suit their research purposes.”

Amino acids are joined together in precise sequences to form proteins, and several of them can undergo chemical transformations that can change the activity of the protein for better or worse. One such transformation is a process called phosphorylation, when a compound called phosphate is added to an amino acid, changing its shape and charge. Previously, Hunter showed that phosphorylation on the amino acid tyrosine can drive cancer progression, a discovery that led to numerous anticancer drugs. More recently, Hunter turned his attention to phosphorylation of the amino acid histidine (which creates phosphohistidine), suspecting that the process might also play a role in human disease.

Hunter developed a suite of antibodies able to bind to phosphohistidine in proteins, and used chemically stabilized phosphohistidine analogues to develop a series of monoclonal antibodies that could recognize these forms. The next step was to understand exactly how the antibodies are able to bind to phosphohistidine. This led Hunter to collaborate with Ian Wilson, the Hansen Professor of Structural Biology at the Scripps Research Institute and a world-renowned expert in using protein crystallography to define antibody structures, to study the structures of the phosphohistidine antibodies.

“My long-term colleague Tony and I have been collaborating on this project for the past seven years,” says Wilson. “We have obtained new insights into how antibodies can evolve to recognize phosphates linked to proteins, which is very satisfying.”

To find out how phosphohistidine is recognized, they needed to image their antibodies in the act of binding the phosphohistidine, and so formed crystals between each antibody bound to a phosphohistidine peptide.

“To understand the molecular interactions between the antibodies and phosphohistidine, we needed to look at them in great detail,” says first author Rajasree Kalagiri, a Salk postdoctoral researcher and expert in X-ray crystallography. “Once we got the antibodies to form crystals, we bombarded those crystals with X-rays to obtain a diffraction pattern. We then applied methods that transform the diffraction pattern into a three-dimensional electron density map, which was then used to discern the atomic structure of the antibodies.”

The two types of antibody crystal structures solved by the team revealed exactly how different amino acids are arranged around the phosphohistidine to bind it tightly. Their five structures more than double the number of phospho-specific antibody structures previously reported, and provide insights into how antibodies recognize both the phosphate and the linked histidine. They also reveal at a structural level how the two types of antibody recognize different forms of phosphohistidine, and this will allow the scientists to engineer improved antibodies in the future.

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Materials provided by Salk Institute. Note: Content may be edited for style and length.

In a new study, University of Illinois Urbana Champaign bioengineering professors Andrew Smith and Mark A. Anastasio, molecular and integrative physiology professor Erik Nelson and nutritional sciences professor Kelly Swanson detail the use of the new technique in mice. The results are published in the journal Science Advances.

Inflammation in adipose tissue presents itself as round complexes of inflammatory tissue called crownlike structures. Previous studies have shown that body fat that contains these structures is associated with worse outcomes of obesity and related metabolic disorders, the study reports.

Previously, researchers were confined to the use of 2D slices of tissue and traditional microscopy, limiting what researchers could learn about them.

To get a better view, the team combined a special type of microscopy that uses a 3D sheet of light rather than a beam, a fat-clearing technique that renders tissue optically transparent, and deep-learning algorithms that help process the large amount of imaging data produced.

The researchers found that the crownlike appearances that gives these structures their name are, in reality, more like 3D shells or concentric spheres surrounding an empty core, Smith said.

“Using our new technique, we can determine the crownlike structures’ volume, the specific number of cells associated with them, as well as their size, geometry and distribution,” Smith said.

This ability led the team to discover that obesity tends to be associated with a prevalence of rare, massive crownlike structures that are not present in the lean state.

“These very large crownlike structures are clustered together and located in the center of the tissue,” Smith said. “And there is no way we could have analyzed this before using our new technique.”

Smith said the research may lead to new drug therapies and new ways to evaluate patients’ metabolic health.

“Right now, we know that some patients are overweight but metabolically healthy, while others are underweight and metabolically unhealthy,” Smith said. “We believe that having the ability to look deep into the microenvironments with fat tissue may unlock some of the reasons why this is.”

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Materials provided by University of Illinois at Urbana-Champaign, News Bureau. Original written by Lois Yoksoulian. Note: Content may be edited for style and length.

A leading cause of SCD in young athletes is arrhythmogenic cardiomyopathy (ACM), a genetic disease in which healthy heart muscle is replaced over time by scar tissue (fibrosis) and fat.

Stephen Chelko, an assistant professor of biomedical sciences at the Florida State University College of Medicine, has developed a better understanding of the pathological characteristics behind the disease, as well as promising avenues for prevention. His findings are published in the current issue of Science Translational Medicine.

Individuals with ACM possess a mutation causing arrhythmias, which ordinarily are non-fatal if managed and treated properly. However, Chelko shows that exercise not only amplifies those arrhythmias, but causes extensive cell death. Their only option is to avoid taking part in what should be a healthy and worthwhile endeavor: exercise.

“There is some awful irony in that exercise, a known health benefit for the heart, leads to cell death in ACM subjects,” Chelko said. “Now, we know that endurance exercise, in particular, leads to large-scale myocyte cell death due to mitochondrial dysfunction in those who suffer from this inherited heart disease.”

Several thousand mitochondria are in nearly every cell in the body, processing oxygen and converting food into energy. Considered the powerhouse of all cells (they produce 90 percent of the energy our bodies need to function properly), they also play another important role as a protective antioxidant.

As mitochondria fail to function properly, and myocyte cells in the heart die, healthy muscles are replaced by scar tissue and fatty cells. Eventually, the heart’s normal electrical signals are reduced to an erratic and disorganized firing of impulses from the lower chambers, leading to an inability to properly pump blood during heavy exercise. Without immediate medical treatment, death occurs within minutes.

Chelko’s research gets to the heart of the process involved in mitochondrial dysfunction.

“Ultimately, mitochondria become overwhelmed and expel ‘death signals’ that are sent to the nucleus, initiating large-scale DNA fragmentation and cell death,” Chelko said. “This novel study unravels a pathogenic role for exercise-induced, mitochondrial-mediated cell death in ACM hearts.”

In addition to providing a better understanding of the process involved, Chelko discovered that cell death can be prevented by inhibiting two different mitochondrial proteins. One such approach utilizes a novel targeting peptide developed for Chelko’s research by the National Research Council in Padova, Italy.

That discovery opens avenues for the development of new therapeutic options to prevent myocyte cell death, cardiac dysfunction and the pathological progression leading to deadly consequences for people living with ACM.

This research was funded by an American Heart Association Career Development Award.

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Materials provided by Florida State University. Original written by Doug Carlson. Note: Content may be edited for style and length.

During an earthquake, a fast slip happens when energy builds up underground and is released quickly along a fault. Blocks of earth rapidly slide against one another.

However, at an Antarctic glacier called Whillans Ice Plain, the earth scientists show that “slow slips” precede dozens of large magnitude 7 earthquakes. “We found that there is almost always a precursory ‘slow slip’ before an earthquake,” said lead author Grace Barcheck, research associate in Earth and Atmospheric Sciences at Cornell University.

Barcheck said that these slow-slip precursors — occurring as far as 20 miles away from the epicenter — are directly involved in starting the earthquake. “These slow slips are remarkably common,” she said, “and they migrate toward where the fast earthquake slip starts.”

Observations before several large tsunami-generating magnitude 8 and 9 earthquakes on subduction zone faults suggest a similar process may have occurred, according to Patrick Fulton, assistant professor and Croll Sesquicentennial Fellow in the Department of Earth and Atmospheric Sciences.

As these faults are mostly offshore and deep underwater, and because it is difficult to know when or where a large earthquake will occur, the start of large earthquakes is generally hard to observe.

To overcome these challenges, the scientists placed GPS sensors above an icy glacial fault at Whillans Ice Plain, where large magnitude 7 earthquakes occur nearly twice a day over a 60-mile-wide area of the glacier.

Within a period of two months in 2014, the group captured 75 earthquakes at the bottom of the Antarctic glacier. Data from GPS stations indicated that 73 — or 96% — of the 75 earthquakes showed a period of precursory slow motion.

The data from the GPS tracking stations and surface seismometers allowed the team to identify how the slow precursory slip triggers the fast earthquake slip.

“Our group was a little surprised to see so many precursors,” Barcheck said.

“In some cases, we can actually see the migration of the earthquake precursor towards where the earthquake begins.”

“Before we pored over the data, I thought that if we saw any precursors before the earthquakes, they would be rare and in the same place as the earthquake epicenter,” she said. “Instead, we found many slow-slip precursors — starting miles from the epicenters and migrating across the fault.”

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Materials provided by Cornell University. Original written by Blaine Friedlander. Note: Content may be edited for style and length.