[Pathology of the cytoskeleton in Alzheimer's disease and disorders related to this disease].

The reported findings suggest that ubiquitination of pathological proteinaceous intracytoplasmic inclusions is not at all specific of AD. On the contrary it appears to be a general biochemical marker for disorders in the degradation of a variety of cytoskeletal and other cytoplasmic proteins. The pattern of affected cytoskeletal components is not specific of AD/SDAT tangles. Tau definitely is present also in PSP tangles and possibly in Pick bodies but not in Lewy bodies. Furthermore, reactivity to tau, although not associated with ubiquitin but with Actin has been described in Hirano bodies. Therefore it has to be considered that the intracytoplasmic accumulation of cytoskeletal protein/ubiquitin complexes in itself is a rather unspecific cellular reaction pattern, possibly a secondary reaction to cell injury of any type especially, however, of neuronal aging. Nevertheless, the manifestation of NFT in an excessive quantity, intensity, and dynamics with severe concomitant lesions as in AD/SDAT undoubtedly is a true pathological and in this sense a disease-specific change.