New 'Unifying Theory' May Explain How Alzheimer's Emerges in The Brain

New 'Unifying Theory' May Explain How Alzheimer's Emerges in The Brain Health 05 April 2026 By Ivan Farkas (Maciej Frolow/Stone/Getty Images) The origins of Alzheimer's remain contentious, but a new study suggests the disease may emerge as two key proteins compete inside brain cells. Alzheimer's disease, the most common form of dementia, has long been associated with the build-up of two proteins in the brain: amyloid-beta and tau. This new study ties those two together, offering a " unifying theory " that, according to the team of chemists proposing it, resolves some conflicting ideas about Alzheimer's. Amyloid-beta peptides are sticky fragments of a larger protein that clump together to form plaques in the brains of people with Alzheimer's . These plaques, it's thought, can emerge some 20 years before symptoms appear. But some research suggests that tau tangles, knots of misfolded tau proteins that form inside diseased neurons, are a better indicator of cognitive status in Alzheimer's than amyloid-beta plaques. Normally, tau stablizes microtubules , the internal scaffold of cells, but in Alzheimer's disease, tau detaches from microtubules, clogging up cells. A visualization of the competition to bind to microtubules, shown in blue, by amyloid-beta peptides and tau proteins, shown in yellow and green, respectively. ( Ryan Julian/UCR ) These two hallmarks of Alzheimer's disease have been called into question in recent years , but they remain a major focus of research – with neuroscientists trying to figure out which forms first, what effect they each have, and if they truly do cause the disease or are just a symptom of it. "In addition to having dementia , [an] Alzheimer's diagnosis requires both [amyloid-beta] and tau buildup in the brain," explains Ryan Julian, a chemistry professor at the University of California, Riverside, and the study's senior author. "But many labs focus on the role of one and ignore the other." A healthy neuron and a diseased neuron, showing the hallmarks of Alzheimer's disease: tau tangles and amyloid-beta plaques. ( BruceBlaus/Wikimedia Commons ) To investigate, Julian and his colleagues conducted a series of protein binding studies, focusing on how amyloid-beta and tau interact around microtubules. Noticing that amyloid-beta peptides resembled, in sequence, the part of tau proteins that attach to microtubules, the team mixed the two proteins together in solution, along with tubulin , the building block of microtubules. "Our work shows amyloid beta and tau compete for the same binding sites on microtubules, and that [amyloid-beta] can prevent tau from functioning correctly," says Julian. Using fluorescently labeled amyloid-beta, the researchers could see when amyoid-beta peptides 'stole' the binding sites normally used by tau proteins. The researchers also 'tempted' amyloid-beta with another common protein, myoglobin, and found that amyloid-beta peptides still preferred binding to microtubules – meaning they weren't jus