Study Shows Amyloid Beta and Tau Compete for Microtubule Binding Sites in Nerve Cells

Researchers at the University of California, Riverside found that amyloid beta can bind to microtubules inside nerve cells with strength comparable to tau and can displace tau from those binding sites. The study, published in Proceedings of the National Academy of Sciences, Nexus, examined what occurs when both proteins are present in the same cell.

Ryan Julian, the study’s lead author and a chemistry professor at UCR, said the part of tau that attaches to microtubules is very similar to amyloid beta.

Using a fluorescent marker, the team observed direct competition at the same sites. “Our work shows amyloid beta and tau compete for the same binding sites on microtubules, and that a-beta can prevent tau from functioning correctly,” Julian said. Tau normally stabilizes microtubules, which serve as internal pathways that move materials within nerve cells.

When amyloid beta occupies those sites, the transport system can lose stability and tau itself can begin to clump and relocate inside the cell. The study also notes that autophagy, the cell’s process for clearing unwanted proteins, becomes less efficient with age. Reduced clearance allows amyloid beta to accumulate inside neurons, increasing the chance it will interfere with tau.

Michael Kane, chief medical officer at Indiana Center for Recovery, said the findings refine rather than reject the amyloid theory. “I see these findings less as a rejection of the amyloid theory and more as a possible link between amyloid beta and tau,” Kane said. He added that the work supplies “a more specific place to look” for how the two proteins interact.

Kane cautioned that the mechanism remains a working model. “A plausible mechanism is not the same as proof that this is what drives Alzheimer’s in patients,” he said. He noted that researchers still need to determine when the interference occurs, in whom, and whether it corresponds to memory loss or functional decline.