A protein that most scientists have thought of primarily as a culprit in Alzheimer's disease turns out to play a critical role in healthy brain function, specifically in the formation and stabilization of long-term memories.
New research published in Nature Communications by Flinders University, in partnership with researchers from the University of New South Wales and Macquarie University, found that tau — a protein widely associated with memory loss in dementia — is essential for organizing and stabilizing memories so they persist over time. The discovery was first published May 17, 2026, and received renewed national attention when ScienceDaily featured it on July 12, 2026.
The paper, titled "Tau T205 phosphorylation modulates engram cell recruitment and remote memory in mice," was published in Nature Communications (DOI: 10.1038/s41467-026-73207-9). Its findings challenge a long-standing assumption in the field — that tau is not required for normal memory function and only becomes relevant in the context of disease.
Why This Matters
Tau has been at the center of Alzheimer's research for decades. The protein, which normally helps stabilize structures inside neurons, becomes abnormally phosphorylated in Alzheimer's disease — meaning it acquires extra chemical tags that cause it to clump into neurofibrillary tangles. Those tangles are one of the two defining pathological features of Alzheimer's disease (the other is amyloid-beta plaques), and they correlate strongly with the cognitive decline patients experience.
The standard narrative has been: normal tau is fine; abnormal tau causes problems. The therapeutic implication — being pursued by multiple drug developers — has been to reduce tau or prevent its abnormal modification.
This study complicates that picture in a clinically meaningful way. The researchers conclude that tau should be viewed not only as a protein involved in Alzheimer's disease, but also as a fundamental regulator of how the brain organizes, stores, and retrieves lasting memories. That new perspective could matter significantly for how Alzheimer's treatments are designed — because eliminating or aggressively suppressing all tau activity could, in theory, impair the very memory mechanisms those treatments are meant to preserve.
What We Know So Far
The research focused on a specific type of memory: remote memory — memories recalled days or weeks after an experience. Remote memory depends on the brain consolidating and stabilizing the memory trace over time, a process the researchers found is tau-dependent.
At the heart of this process are engram cells — specialized groups of brain cells that form the physical trace of a memory. During learning, only a small subset of available neurons is recruited to store a given experience. The selection and coordination of these cells — the process that determines which specific neurons carry a memory — is where tau's role was identified.
The study found that tau undergoes a subtle chemical modification known as phosphorylation at a specific site called T205 during learning. This controlled, low-level phosphorylation helps coordinate which neurons become part of the memory trace. Crucially, 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.
When the researchers studied mice without functional tau, they found that while those mice could still learn and form short-term memories, their long-term memory recall was weaker. Memory traces still existed in those mice — when researchers directly stimulated the engram cells electrically, memories could be accessed. This means tau is specifically required to link natural cues — sights, sounds, smells — to memory recall, rather than to store the memory itself.
When abnormal tau similar to that found in Alzheimer's disease was introduced into the system, it disrupted both the formation of new memories and the ability to access existing ones — and was associated with abnormal brain activity patterns.
Where the Research Comes From
The study was led by Flinders University's College of Medicine and Public Health, with co-investigators from Macquarie University (including Lars M. Ittner, whose laboratory has been a major center for tau biology research) and the University of New South Wales. Funding came from the National Health and Medical Research Council of Australia, the Australian Research Council, and the BrightFocus Foundation.
The full paper citation is: Renée Kosonen, Kristie Stefanoska, Yijun Lin, Samantha Edwards, Emmanuel Prikas, Josefine Bertz, Anne Poljak, Lars M. Ittner, and Arne Ittner. "Tau T205 phosphorylation modulates engram cell recruitment and remote memory in mice." Nature Communications, 2026. DOI: 10.1038/s41467-026-73207-9.
What Doctors and Experts Say
Associate Professor Arne Ittner, senior author and neuroscientist at Flinders' College of Medicine and Public Health, stated that why some memories last while others fade has long puzzled scientists, and the 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.
Renée Kosonen, one of the lead authors and a researcher at Flinders' Neuroscience and Dementia Research center, said the findings show that tau helps determine which cells are selected to store a memory, shaping how an experience forms a lasting memory trace.
The researchers were careful to note the study's limitations: the observations are in mice and do not directly translate to human brain function or dementia; however, they believe the findings offer important insights that could help guide the development of future treatments.
What the Evidence Shows and What It Does Not
MedicalDaily Evidence Check
- Study type: Mouse study using genetic models with and without tau, and with pathological tau; multimodal behavioral and electrophysiological analysis
- Published in: Nature Communications, May 17, 2026 (DOI: 10.1038/s41467-026-73207-9)
- Lead institutions: Flinders University, University of New South Wales, Macquarie University
- What it found: Normal, low-level tau phosphorylation at T205 is required for coordinating engram cell selection and stabilizing long-term remote memory; mice without tau form memories that are weaker at recall; abnormal tau (similar to Alzheimer's disease) disrupts both new memory formation and existing memory recall
- What it did not prove: That these findings directly apply to human memory or Alzheimer's disease; that tau-targeting drugs will improve or impair human memory based on these results
- What it means for treatment: The dual role of tau — essential in normal amounts for memory, toxic in abnormal forms — adds complexity to the challenge of designing tau-targeting therapies that spare memory-related functions
- What readers should know: This is animal research that advances basic understanding of tau biology. It does not change current Alzheimer's clinical recommendations or alter the standard of care.
Who This Research Matters To
This research is most directly relevant to:
- Researchers studying tau biology, Alzheimer's disease mechanisms, and memory consolidation
- Drug developers working on tau-targeting therapies, who now need to account for the dual role of tau in healthy and diseased states
- Patients with Alzheimer's disease and their families who are following the science of tau and whether targeting it will produce treatment benefits
- Older adults concerned about memory and cognitive aging, who may find it useful to know that the same protein involved in memory loss in Alzheimer's also plays a role in normal memory formation
Symptoms and Warning Signs to Watch For
This research does not change clinical guidance on Alzheimer's disease symptoms or screening. Warning signs that warrant a clinical evaluation include:
- Memory loss that disrupts daily life, particularly forgetting recently learned information
- Challenges in planning or problem-solving
- Difficulty completing familiar tasks
- Confusion about time or place
- Trouble understanding visual images or spatial relationships
- New problems with words in speaking or writing
- Misplacing things and being unable to retrace steps
- Decreased or poor judgment
- Withdrawal from work or social activities
- Changes in mood or personality
If you or a family member notices several of these changes, contact a clinician for a comprehensive evaluation. Early diagnosis of Alzheimer's disease is important for planning, support, and access to clinical trials and available treatments.
What You Can Do Now
- If you have concerns about memory changes in yourself or a loved one, contact a primary care physician for a baseline cognitive evaluation. Do not wait for dramatic symptoms before seeking assessment.
- Follow ongoing research at the Alzheimer's Association and BrightFocus Foundation , which fund tau research and publish regular research updates for lay audiences.
- Enroll in the Alzheimer's Prevention Registry if you are interested in being notified about clinical trial opportunities for people at risk for Alzheimer's disease.
- Maintain evidence-based lifestyle practices associated with reduced dementia risk: regular physical activity, cardiovascular health management, quality sleep, cognitive engagement, and social connection.
Cost and Access: What Patients Should Know
No new treatments have emerged from this research. For people currently living with Alzheimer's disease, the Alzheimer's Association's Helpline at 1-800-272-3900 provides 24/7 support, care advice, and clinical trial referrals. Medicare covers many Alzheimer's-related diagnostic services, and some Alzheimer's medications (including newer amyloid-targeting drugs) may require prior authorization.
For families navigating Alzheimer's care, the Alzheimer's Association Care Navigator tool and the ADEAR Center provide free, evidence-based resources.
What Happens Next
The research team at Flinders University and Macquarie University is expected to extend this work into human-relevant models to determine whether tau T205 phosphorylation plays a similar memory-coordinating role in human neurons and brain tissue. The clinical implication — that tau-targeting drugs may need to be designed to preserve or modulate, rather than simply eliminate, tau activity — is expected to inform the design of next-generation Alzheimer's drug programs.
MedicalDaily will report on any follow-up studies from this research group and on clinical trial developments in tau-targeted Alzheimer's therapy.
The Bottom Line
A protein best known for causing memory loss in Alzheimer's disease has a second, previously underappreciated job: helping healthy brains form memories that last. Tau coordinates the selection and activity of engram cells — the brain's memory-storing units — during the stabilization of long-term memories. When tau is absent, memories form but fade faster. When abnormal tau is present, both new memory formation and existing memory recall are impaired. The finding adds nuance to a field that has long seen tau primarily as a target to eliminate. Future Alzheimer's treatments may need to account for tau's essential role in healthy brain function — not just its harmful role in disease.
