Arc Protein Carries Alzheimer's Tau Between Neurons
SkimNews Take
Identifying the carrier protein (Arc) rather than just the cargo (toxic tau) shifts the therapeutic target to intercellular transport machinery, potentially avoiding the difficulty of clearing a protein that neurons also produce normally.
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- University of Utah Health researchers identified the brain protein Arc as a vehicle that carries toxic Tau between neurons in Alzheimer's disease by exploiting extracellular vesicles (EVs) that normally shuttle signals between cells.
- In mice lacking Arc, Tau transfer between neurons was "severely, severely reduced" — "almost gone," according to first author Mitali Tyagi, PhD, who conducted the work in the Shepherd Lab and is now at Washington University in St. Louis.
- The protein has a dual role: Arc also helps damaged neurons expel excess toxic Tau, so mice without Arc saw sick neurons die faster because Tau became trapped inside at toxic levels.
- Senior author Jason Shepherd, PhD, said the most promising therapeutic angle is intercepting Tau-laden EVs between diseased and healthy neurons rather than eliminating Tau itself, but stressed the work is "far away from" any human treatment.
- The team also detected Arc-and-Tau-containing vesicles in human brain tissue, hinting the same mechanism may extend beyond mice.
- The study, "Arc mediates intercellular tau transmission via extracellular vesicles," was published June 30, 2026, in Cell, with funding from the NIH, Alzheimer's Association, Chan-Zuckerberg Initiative, and others.
Why it matters: Identifying Arc as Tau's ride between neurons gives drug developers a fresh target — the extracellular vesicles themselves — distinct from strategies aimed at clearing Tau directly. The dual role of Arc (protective early, damaging later) means any therapy must carefully intervene without disabling the brain's own Tau-clearing mechanism.
