The tangled web in Alzheimer's protein deposits is more complex than once thought

"Since neurofilaments are the predominant protein in nerve cells, our study suggests that we should refocus our research on the biology of these filamentous proteins in an effort to understand how they are normally regulated and deregulated in response to human aging," said Harish C. Pant, Ph.D., a senior researcher involved in the work from the Cytoskeletal Regulatory Protein Section of the Laboratory of Neurochemistry at the National Institute of Neurological Disorders and Stroke at the National Institutes of Health in Bethesda, Maryland.

To make their discovery, Pant and colleagues identified normal and abnormal proteins present in autopsy samples of the brains of Alzheimer's disease victims. Then they isolated and purified the tangles (which are knots of abnormally aggregated filaments that fill and compromise nerve cells) from the autopsy samples and compared their protein composition to age- and post mortem-matched samples of brains from patients who died of other causes, such as accidents. Through a combination of improved instrumentation and informatics, it was possible to resolve the mixture of proteins successfully and identify the novel Alzheimer's disease proteins. Previous research suggested that only one protein, called "tau," is present in these tangles.

"This is a breakthrough of great importance: tau is not the only target," said Gerald Weissmann, M.D., Editor-in-Chief of the FASEB Journal. "Before this discovery, we approached these tangles as if they were woven of one piece of string. Now we know that there are at least three proteins involved, we're much closer to untangling the Alzheimer's web. Without question, discoveries like this bring us closer than ever to advanced Alzheimer's treatments, and it is a good example of why NIH funding is among the best investments our nation can make toward improving health and well being."

More information: Parvathi Rudrabhatla, Howard Jaffe, and Harish C. Pant. Direct evidence of phosphorylated neuronal intermediate filament proteins in neurofibrillary tangles (NFTs): phosphoproteomics of Alzheimer's NFTs. FASEB J. November 2011 25:3896-3905; doi:10.1096/fj.11-181297

Provided by Federation of American Societies for Experimental Biology