Scientists from the National Institutes of Health, Bethesda, Maryland, USA, have discovered that the protein tangles which are a hallmark of Alzheimer involve at least three different proteins rather than just one. The additional proteins are neurofilaments and vimentin. Previous research suggested that only one protein, tau, is present in these tangles.

The scientists identified normal and abnormal proteins present in autopsy samples of the brains of Alzheimer’s disease victims. 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.

• Direct evidence of phosphorylated neuronal intermediate filament proteins in neurofibrillary tangles (NFTs): phosphoproteomics of Alzheimer’s NFTs,
  Parvathi Rudrabhatla, Howard Jaffe, Harish C. Pant,
  FASEB J. 2011, 25, 3896–3905.
  DOI: 10.1096/fj.11-181297