Unique protein bond enables learning and memory

Two proteins have a unique bond that enables brain receptors essential to learning and memory to not only get and stay where they’re needed, but to be hauled off when they aren’t, researchers say.

NMDA receptors increase the activity and communication of brain cells and are strategically placed, much like a welcome center, at the receiving end of the communication highway connecting two cells. They also are targets in brain-degenerating conditions such as Alzheimer’s and Parkinson’s.

In a true cradle-to-grave relationship, researchers have found the scaffolding protein, SAP102, which helps stabilize the receptor on the cell surface, binds with a subunit of the NMDA receptor called GluN2B at two sites, said Dr. Bo-Shiun Chen, neuroscientist at the Medical College of Georgia at Georgia Health Sciences University.

While one binding site is the norm, these proteins have one that’s stronger than the other. When it’s time for the normal receptor turnover, the stronger bond releases and the lesser one shuttles the receptor inside the cell for degradation or recycling.

“One binding site is involved in stabilizing the receptor on the cell surface and the other is important in removing the receptor. We think it’s a paradigm shift; we’ve never thought about the same scaffolding protein having two roles,” said Chen, corresponding author of the study in the journal Cell Reports.