A team of international researchers has discovered a biological explanation for long-term memories “focusing on the role of the KIBRA molecule”, which acts as a “glue” for other molecules, thus solidifying memory formation.
It has long been established that neurons store information in memory in a pattern of strong synapses and weak synapses.
The molecules in synapses are unstable, constantly moving in neurons, and replaced over the course of hours to days, which raises the question: How can memories be stable for years and even decades?
“Previous efforts to understand how molecules store long-term memory have focused on the individual actions of single molecules,” explains Andre Fenton, a professor of neuroscience at New York University and one of the study’s lead researchers. “Our study shows how they work together to ensure permanent memory storage.”
In a study conducted on laboratory mice, researchers focused on the role of the KIBRA molecule, or a protein that is expressed in the kidneys and brain, as it is genetically linked to human memory performance.
They focused on KIBRA's interactions with other molecules important for memory formation, including protein kinase Mzeta (PKMzeta), which is the most important molecule for strengthening normal synapses in mammals, but which degrades after a few days.
Experiments revealed that KIBRA is the “missing link” in long-term memories, acting as a “persistent synaptic tag,” or glue, that sticks to strong synapses and PKMzeta while avoiding weak synapses.
“During memory formation, synapses involved in the process are activated, and KIBRA is selectively placed at these synapses,” says Todd Sacktor, a professor at SUNY Downstate Health Sciences who co-led the study. “PKMzeta then binds to the KIBRA tag to create a persistent synapse, which keeps these synapses strong.”
The study showed that breaking the KIBRA-PKMzeta bond erases old memory.
The study was published in the journal Science Advances.