Fight Aging!

If verified by other laboratories, this seems like a meaningful step forward in understanding the physical structure of memory. A greater knowledge of the biological basis for memory storage has important applications in many fields, not just the obvious ones in medicine:

Researchers have shown how how prion-like proteins are critical for maintaining long-term memories in mice, and probably in other mammals. When long-term memories are created in the brain, new connections are made between neurons to store the memory. But those physical connections must be maintained for a memory to persist, or else they will disintegrate and the memory will disappear within days. Many researchers have searched for molecules that maintain long-term memory, but their identity has remained elusive.

Prions - a name derived from the words protein infectious particles - are a unique class of proteins. Unlike other proteins, they are not only able to self-propagate but also to induce other proteins to take on their alternative shape. When prions form in a cell, notably in a neuron, they cause damage by grouping together in sticky aggregates that disrupt cellular processes. In contrast, functional prion proteins can play a physiological role in the cell and do not contribute to disease.

Researchers first identified functional prions in the giant sea slug (Aplysia) and found they contribute to the maintenance of memory storage. More recently, they searched for and found a similar protein in mice, called CPEB3. In one of many experiments, the researchers challenged mice to repeatedly navigate a maze, allowing the animals to create a long-term memory. But when the researchers knocked out the animal's CPEB3 gene two weeks after the memory was made, the memory disappeared.

The researchers then discovered how CPEB3 works inside the neurons to maintain long-term memories. "Like disease-causing prions, functional prions come in two varieties, a soluble form and a form that creates aggregates. When we learn something and form long-term memories, new synaptic connections are made, the soluble prions in those synapses are converted into aggregated prions. The aggregated prions turn on protein synthesis necessary to maintain the memory." As long as these aggregates are present long-term memories persist. Prion aggregates renew themselves by continually recruiting newly made soluble prions into the aggregates. "This ongoing maintenance is crucial."

A similar protein exists in humans, suggesting that the same mechanism is at work in the human brain, but more research is needed. "It's possible that it has the same role in memory, but until this has been examined, we won't know. There are probably other regulatory components involved. Long-term memory is a complicated process, so I doubt this is the only important factor."

Link: http://www.eurekalert.org/pub_releases/2015-07/cumc-lma070215.php