Tubulin immunopositive structures resembling intracellular neurofibrillary tangles

Tau protein promotes microtubule assembly. When aberrantly phosphorylated, it forms the core of neurofibrillary tangles (NFTs). We investigated by immunohistochemistry whether microtubules might also be involved in NFT formation. We found beta-tubulin immunoreactive NFT-like structures in Alzheimer disease, and, more frequently, in the parkinsonism dementia complex of Guam (bodig disease) and Down Syndrome. The beta-tubulin immunoreactive structures were intracellular and appeared at an early stage of tangle development. This may indicate an involvement of tubulin in NFT formation.