Photo Credit: Vitaly Gariev
Scientific Frontline: Extended "At a Glance" Summary: Tau Protein's Role in Long-Term Memory
The Core Concept: The tau protein, heavily associated with cognitive decline in Alzheimer's disease, acts as a fundamental neurological regulator required for organizing, stabilizing, and recalling long-lasting remote memories.
Key Distinction/Mechanism: While tau is not necessary for initial learning or short-term recall, a controlled, low-level chemical modification called phosphorylation allows it to selectively recruit specific brain cells during memory encoding. By minimizing excess brain "noise," tau ensures memory formation is precise; without it, memory traces still form but cannot be naturally accessed through standard sensory cues.
Major Frameworks/Components:
- Engram Cells: Specialized groups of neurons that form the physical, stored trace of a specific memory or experience.
- Remote Memory: Long-term memories that persist and are successfully recalled days or weeks after an initial event.
- Tau Phosphorylation: A subtle chemical modification (specifically tau T205 phosphorylation) that coordinates and regulates the activity of engram cells during the learning process.
- Encoding Window: The critical time frame during learning where tau actively determines which specific neural cells are selected to house the memory.
Branch of Science: Neuroscience, Molecular Biology, and Neurology.
Future Application: These foundational insights into tau's regulatory function in mice models will guide the development of future targeted treatments for Alzheimer's disease, focusing on correcting impaired memory organization and retrieval.
Why It Matters: This discovery fundamentally shifts the understanding of tau from being merely a disease-associated pathology to an essential component of healthy cognitive function. It provides a clearer explanation for why memory loss in dementia can occur even when a patient's capacity for initial, short-term learning remains intact.
New research has uncovered how a protein strongly linked to Alzheimer’s disease plays a critical role in forming long-lasting memories—opening up new directions for future dementia treatments.
The study, led by Flinders University in collaboration with researchers from the University of New South Wales and Macquarie University, was published in Nature Communications and shows that tau—a protein widely associated with memory loss in dementia—is essential for organizing and stabilizing memories so they persist over time.
The research focused on "remote memory" in mice—memories recalled days or weeks after an experience—and found that while tau is not required for initial learning or short-term recall, it is critical for ensuring memories remain strong over the long term.
While these findings were observed in mice and do not directly translate to human brain function or dementia, they offer important insights that could help guide the development of future treatments.
Senior author and neuroscientist Associate Professor Arne Ittner says the work helps explain why memory loss in dementia can develop even when initial learning appears intact.
"Why some memories last while others fade has long puzzled scientists, and our study shows that tau plays a key role in how the brain forms long-lasting memories. Without it, memories can still form in the moment, but they are weaker," says Associate Professor Ittner from the College of Medicine and Public Health at Flinders University.
At the heart of this process are specialized groups of brain cells known as "engram cells," which form the physical trace of a memory. During learning, only a small subset of these cells is recruited to store a given experience.
The study shows that tau acts during this critical encoding window, helping determine which cells are selected to store a memory.
One of the lead authors, Renée Kosonen, says tau functions as a kind of organizer, ensuring memory formation is precise.
"Our findings show that tau helps determine which cells are selected to store a memory, shaping how an experience forms a lasting memory trace," says Ms. Kosonen, a researcher at Flinders's Neuroscience and Dementia Research.
Importantly, the researchers found that tau helps prevent excess or "noise" activity in the brain, allowing only a specific group of cells to become part of the memory trace, resulting in clearer, more stable memories.
The researchers also identified a key molecular mechanism behind this effect. During learning, tau undergoes a subtle chemical modification known as phosphorylation, which helps coordinate the activity of engram cells.
While abnormal tau phosphorylation is a hallmark of Alzheimer’s disease, this study shows that controlled, low-level phosphorylation plays an essential role in normal brain function.
Interestingly, the researchers found that memory traces still exist even without tau—and could be accessed by directly stimulating engram cells. This suggests tau is specifically required to link natural cues, such as sights or sounds, to memory recall, rather than to store the memory itself.
The study also sheds light on how abnormal tau disrupts memory in dementia. When disease-associated forms of tau were present in engram cells during learning, they interfered with the formation of new memories. When present later, they disrupted the brain’s ability to access existing memories.
These disruptions were linked to abnormal brain activity, suggesting that memory problems in dementia may arise not only from lost memories but also from impaired organization and retrieval.
"Knowing how tau supports the formation and recall of memory could help us better understand what goes wrong in memory loss," says Associate Professor Ittner.
"Future research will hopefully be able to confirm concepts developed in our study in human memory and show their implication in dementia."
The researchers say the findings position tau not just as a disease-related protein but also as a fundamental regulator of how memories are organized and retained—providing new insight into both healthy brain function and the mechanisms underlying memory loss in Alzheimer’s disease.
Funding: This work was supported by funding from the National Health and Medical Research Council (grant nos. 1143978, 1176628, and 2028265) to A.I. and (grant nos. 2029740 and 2020624) to L.I.; from the Australian Research Council (grant nos. DP200102396 and DP220101900) to A.I. and (grant no. DP240101654) to L.I.; from the Flinders Foundation and Flinders University to A.I.; from the BrightFocus Foundation (grant no. A2022022F) to K.S.; and from the Dementia Australia Research Foundation to A.I., K.S., and E.P. K.S. was supported by a Scientia Professor Henry Brodaty Postdoctoral Fellow of the Dementia Australia Research Foundation. A.I. was supported by a National Health and Medical Research Council Emerging Leadership grant. Microscopy Australia is supported by NCRIS and the government of South Australia at Flinders Microscopy and Microanalysis (ROR: 04z91ja70) and Flinders University (ROR: 01kpzv902).
Published in journal: Nature Communications
Title: Tau T205 phosphorylation modulates engram cell recruitment and remote memory in mice
Authors: Renée Kosonen, Kristie Stefanoska, Yijun Lin, Samantha Edwards, Emmanuel Prikas, Josefine Bertz, Anne Poljak, Lars M. Ittner, and Arne Ittner
Source/Credit: Flinders University
Edited by: Scientific Frontline
Reference Number: ns052526_01