Tau proteins are the building blocks of neurofibrillary tangles (NFTs) found in a range of neurodegenerative tauopathies, including Alzheimer's disease. Recently, we demonstrated that tau is extensively post-translationally modified by lysine acetylation, which impairs normal tau function and promotes pathological aggregation. Identifying the enzymes that mediate tau acetylation could provide targets for future therapies aimed at reducing the burden of acetylated tau. Here, we report that mammalian tau proteins possess intrinsic enzymatic activity capable of catalyzing self-acetylation. Functional mapping of tau acetyltransferase activity followed by biochemical analysis revealed that tau uses catalytic cysteine residues in the microtubule-binding domain to facilitate tau lysine acetylation, thus suggesting a mechanism similar to that employed by MYST-family acetyltransferases. The identification of tau as an acetyltransferase provides a framework to further understand tau pathogenesis and highlights tau enzymatic activity as a potential therapeutic target.

Lysine acetylation has emerged as a dominant post-translational modification (PTM) regulating tau proteins in Alzheimer’s disease (AD) and related tauopathies. Mass spectrometry studies indicate that tau acetylation sites cluster within the microtubule-binding region (MTBR), a region that is highly conserved among tau, MAP2, and MAP4 family members, implying that acetylation could represent a conserved regulatory mechanism for MAPs beyond tau. Here, we combined mass spectrometry, biochemical assays, and cell-based approaches to demonstrate that the tau family members MAP2 and MAP4 are also subject to reversible acetylation. We identify a cluster of lysines in the MAP2 and MAP4 MTBR that undergo CBP-catalyzed acetylation, many of which are conserved in tau. Similar to tau, MAP2 acetylation can occur in a cysteine-dependent auto-regulatory manner in the presence of acetyl-CoA. Furthermore, tubulin reduced MAP2 acetylation, suggesting tubulin binding dictates MAP acetylation status. Taken together, these results uncover a striking conservation of MAP2/Tau family post-translational modifications that could expand our understanding of the dynamic mechanisms regulating microtubules.

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