Prions Important for Memories

The formation of long-term memories employs the chain-forming habits of prions.  

Feb 19, 2014
Kerry Grens

WIKIMEDIA, MR.CHECKERMost often associated with mad cow and other infectious diseases, prions have a bright side to them, too. A role for prions as memory-forming helpers is emerging, most recently supported by a study this month (February 11) in PLOS Biology revealing the proteins involved in regulating chain-forming prions in neurons.

The results shed light on a cellular dilemma: How can a neuron form a stable complex in a dynamic environment? It’s known that the fruit fly protein Orb2 can act like a prion in neurons, linking up with other Orb2 proteins to form a stable complex. The long-term memory of the fly is damaged without Orb2’s ability to form a chain.

The new study uncovered other proteins complicit in controlling Orb2’s ability to form an oligomer. The proteins increase the stability of one form of Orb2, called Orb2A, which then “seeds” the formation of a chain built by another form, Orb2B. The trigger for these events is electrical activity at a particular synapse, giving the prion-forming mechanism precision in helping to form a stable connection between neuronal neighbors. According to a report in Scientific American, “this, researchers say, means the cell has a mechanism to stabilize some synapses but not others—potentially explaining why some of our memories fade, whereas others last a lifetime.”

“Do you think God created prions just to kill?” Eric Kandel, who did much of the pioneering work on prions and memory, told Scientific American. “These things must have evolved initially to have a physiological function.” Whether that function is the same in humans as it is in fruit flies remains to be seen.