On January 27, a study first summarized in our SfN conference news, on post-translational modifications of the protein tau, appeared in JBC online. First author Diane Cripps, working with Austin Yang at University of Southern California, Los Angeles, and collaborators report full details of a systematic tandem mass spec analysis of tau protein isolated from Alzheimer brain samples. The researchers not only characterize hyperphosphorylation of human tau, but also report that three residues in the microtubule-binding site of soluble tau tend to become ubiquitinated early in the disease. This suggests that ubiquitination might play a role in controlling the stability of microtubules, and it implicates an age-related slowdown of the ubiquitin-proteasome system in the formation of tangles. Read our related conference story for a broad update on recent developments on tau.—Gabrielle Strobel
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- Cripps D, Thomas SN, Jeng Y, Yang F, Davies P, Yang AJ. Alzheimer disease-specific conformation of hyperphosphorylated paired helical filament-Tau is polyubiquitinated through Lys-48, Lys-11, and Lys-6 ubiquitin conjugation. J Biol Chem. 2006 Apr 21;281(16):10825-38. PubMed.