Scientists Discover Alzheimer’s-Linked Proteion’s Surprising Role in Making Memories Last

A new study published in *Nature Communications* reveals tau, a protein strongly associated with Alzheimer’s disease, plays a critical role in forming and preserving long-term memories. Researchers from Flinders University, the University of New South Wales, and Macquarie University discovered tau helps organize memory storage by selecting specific brain cells called engram cells, which encode experiences. Unlike short-term memory, tau is essential for maintaining memories over days or weeks, though it is not required for initial learning or immediate recall. The team studied remote memory in mice, finding tau stabilizes memory traces by reducing excess brain activity, ensuring only relevant cells contribute to memory formation. This process involves tau phosphorylation, a chemical change that coordinates engram cell activity. While abnormal tau phosphorylation is linked to Alzheimer’s, the study shows controlled phosphorylation is necessary for normal memory function. Lead author Renée Kosonen explained tau acts as an organizer, shaping how experiences form lasting memory traces. Senior author Associate Professor Arne Ittner noted that without tau, memories weaken over time, even if they initially form. The research also found memory traces can persist without tau but require it to connect natural cues—like sights or sounds—to memory recall. Abnormal tau disrupted memory formation when present during learning and impaired retrieval when introduced later, suggesting its role in memory problems in dementia stems from altered brain activity patterns. The findings offer new insights into why some memories fade while others endure, potentially guiding future dementia treatments by targeting tau’s function in memory stabilization.