IN THIS ISSUE .
June 18, 2008
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Like the iris in a camera lens that controls light, the lid of this barrel-shaped molecule opens and closes to control how proteins fold into the unique shapes that determine their function. The exact manner by which proteins fold has been a mystery. Scientists knew that some proteins fold inside these molecules, called chaperonins, but they couldn’t see how. This movie of the chaperonin TRiC literally unlocks the door, showing that the opening’s widening and narrowing dictates how proteins fold or unfold. The advance also offers new details on how a protein lines up inside the chaperonin and folds once the door closes. Courtesy of molecular biologist Judith Frydman, Stanford University.
This work also was supported by the NIH Roadmap for Medical Research.
Many people are always looking for ways to lose weight and control their appetite and blood sugar levels. Endocrinologist Anthony Means and his team of researchers at Duke University Medical Center have been, too—but in mice. The team studied the brain enzyme CaMKK2, known to activate another enzyme involved in appetite stimulation. When Means and colleagues blocked CaMKK2 activity in mice that normally produce the enzyme, they found that the rodents ate less and lost weight. They also saw that the absence of CaMKK2 improved glucose tolerance and insulin sensitivity. Although preliminary, the results point to a potential drug target for appetite control, weight loss, and blood sugar management.
NIH’s National Institute of Diabetes and Digestive and Kidney Diseases also supported this work.
More than a million Americans are living with HIV/AIDS. Their survival depends largely on drugs called protease inhibitors that prevent the virus from maturing and replicating. Some of the efforts to improve treatment have focused on finding other ways to disable the HIV-1 protease enzyme. A new lead comes from University of Michigan chemist Heather Carlson. Using computer models, the Carlson group developed a small molecule that blocked HIV-1 protease activity in a manner different from existing drug treatments. More research needs to be done, but the work could guide the way for developing a new class of AIDS drugs.
Researchers led by geneticist Jasper Rine of the University of California, Berkeley, have found another reason to delve into your genes. Using yeast as an experimental tool to study the expression of human genetic variants, Rine’s team discovered that a vitamin supplement can tune up the activity of a human enzyme. The study focused on variants of an enzyme that requires folate to function properly. The researchers expressed the gene variants in yeast and added more folate to the organisms’ diet, boosting the activity of nearly all the variants. While the work offers promising preliminary results, its application to human health has yet to be explored.
Protein fibers in the brain can misfold and form amyloid plaques that clutter nerve cells and trigger Alzheimer’s disease and other neurodegenerative disorders. Things may clear up, however, with recent discoveries by a team led in part by Massachusetts Institute of Technology molecular biologist Susan Lindquist. The researchers found that the small molecule DAPH selectively targeted amyloid fibers made from ABeta peptide—the toxic peptide in Alzheimer’s disease—and converted them to a form unable to grow. DAPH also worked on yeast amyloid proteins. Dismantling these fibers could influence the development of treatments for a host of neurodegenerative diseases.
NIH’s National Institute on Aging also supported this work.