Biomedical Beat - A monthly digest of research news from NIGMS

IN THIS ISSUE . . .
October 18, 2005

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The National Institute of General Medical Sciences (NIGMS), one of the National Institutes of Health, supports all research featured in this digest. Although only the lead scientists are named, coworkers and other collaborators also contributed to the findings. To read additional news items, visit NIGMS News.

Cool Image: Mapping Brain Differences

Image of the human brain using color and shapes to show neurological differences between two people.
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This image of the human brain uses colors and shapes to show neurological differences between two people. The blurred front portion of the brain, associated with complex thought, varies most between the individuals. The blue ovals mark areas of basic function that vary relatively little. Visualizations like this one are part of a project to map complex and dynamic information about the human brain, including genes, enzymes, disease states, and anatomy. The brain maps represent collaborations between neuroscientists and experts in math, statistics, computer science, bioinformatics, imaging, and nanotechnology. Courtesy of Arthur Toga, a neuroscientist at the University of California, Los Angeles, and head of the Center for Computational Biology, which is supported by the bioinformatics and computational biology component of the NIH Roadmap for Medical Research.

CCB home page (no longer available)
NIH Roadmap home page

Researchers Find Fountain of Youth in Yeast

Ever heard that drastically cutting calories can help you live longer? While this claim has not yet been proven in humans, basic researchers working with simple organisms have observed a link between eating very little and living longer. Some have shown that growing yeast cells in a low-calorie broth can keep these cells youthful by blocking the deadly build-up of toxic amounts of extra DNA. Geneticist David Sinclair of Harvard Medical School and microbiologist Su-Ju Lin of the University of California, Davis, have now identified a trio of genes in a family of proteins called sirtuins that account for the life-extending effects of caloric restriction in yeast. The study also suggests that sirtuins may contribute to health and lifespan in other organisms, including humans.

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Sinclair lab home page
Lin home page
Article abstract (from the September 16, 1005 issue of Science)

Hope for Children with Fatal Aging Syndrome

Cells containing the mutant form of lamin A that causes the aging syndrome. The aberrant, irregularly shaped nuclei are in green. Courtesy of Michaelis.
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Caption: Cells containing the mutant form of lamin A that causes the aging syndrome. The aberrant, irregularly shaped nuclei are in green. Courtesy of Michaelis.

Thanks to an earlier discovery and some scientific detective work, a compound being tested for treating cancer may help children with Hutchinson-Gilford progeria syndrome—a rare, fatal, premature aging condition. Susan Michaelis, a cell biologist at Johns Hopkins University, had been studying enzymes that modify the lamin A protein when geneticists pinpointed a mutation in the lamin A gene as the source of the syndrome. Michaelis followed her hunch and now has shown that the genetic flaw shackles the lamin A protein to a fatty chemical group, causing the cellular abnormalities seen in children with the condition. The compound being tested frees lamin A from its fatty appendage and may prove beneficial in children with the syndrome.

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Michaelis home page
Article abstract (from the October 4, 2005 issue of PNAS)

Approach Offers Proof of Principle for Studying Membrane Proteins

Repeated structure of a voltage-dependent potassium ion channel. Courtesy of Science.
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Caption: Repeated structure of a voltage-dependent potassium ion channel. Courtesy of Science.

With the help of a special group of proteins embedded in the outer membrane of cells, our nerves send signals, our muscles flex, and our hormones get secreted. Yet these medically important molecules remain relatively mysterious, partly because they aren’t abundant in their purest form. A team of scientists led by Roderick MacKinnon, a structural biologist and Nobel laureate at Rockefeller University, has now successfully produced enough of a mammalian membrane protein in a simple organism and determined its structure. The protein is called a voltage-dependent potassium ion channel, and it helps transmit electrical signals into and out of heart and nerve cells. The combination of techniques the researchers used to express, purify, crystallize, and visualize the protein could open the door to studying other membrane proteins involved in health and disease.

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MacKinnon lab home page
Article abstracts (from the August 5, 2005 issues of Science)

Beta-Blockers Could Be Risky for Some Heart Patients

Many heart patients take medications called beta-blockers, which lower blood pressure and slow heart rate, to reduce the risk of heart attacks and prolong survival. But beta-blockers also increase deaths in heart patients with certain genetic profiles, according to new research by pharmacologist Howard McLeod of the Washington University in St. Louis School of Medicine. Working as part of the NIH Pharmacogenetics Research Network, McLeod and his collaborators focused on two genes, ADRB1 and ADRB2, that interact with beta-blockers. They looked at the composition of these genes in more than 700 patients hospitalized for heart attacks or unstable angina, many of whom were sent home on beta-blockers. Patients who took beta-blockers and who had certain common versions of ADRB2 were about three times more likely to die within three years as those with other versions of the gene or those not taking beta-blockers. This discovery will help doctors predict whether the benefits of beta-blockers outweigh the risks for some patients.

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McLeod home page
PGRN home page
Article abstract (from the September 28, 2005 issue of JAMA)

NIGMS-Supported Chemists Win Nobel Prize

Robert Grubbs of the California Institute of Technology and Richard Schrock of the Massachusetts Institute of Technology won the 2005 Nobel Prize in chemistry. The two scientists, who received the prize along with French chemist Yves Chauvin, worked independently to develop molecules called catalysts that promote powerful bond-forming reactions. The catalysts have a wealth of applications in basic research, drug development, and materials preparation. NIGMS has provided nearly $12 million in funding to the U.S. chemists over two decades. Since 1962, the Institute has supported the work of 59 Nobel laureates.

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Grubbs home page
Schrock home page