BRC-BIO: Mechanistic insights into AMPA receptor trafficking during long-term potentiation

This project will explore molecules involved in memory formation, a process that relies on precisely orchestrated communication between neurons. Specifically, this work will focus on how neurons populate their membranes with receptors, known as “AMPA” receptors, that can respond to neurotransmitters. This process requires intracellular membrane vesicles to fuse with the plasma membrane of neurons.

Though membrane fusion has been studied for decades, the regulation of membrane fusion in AMPA receptor (AMPAR) delivery is still poorly understood. This project will describe key steps in the delivery process and aims to identify novel proteins involved in receptor trafficking during learning and memory. Together, these aims will advance the understanding of how memories form.

This work will be performed primarily by undergraduates, both in mentored research projects and in a course-based undergraduate research experience (CURE). These efforts will significantly expand the training opportunities available to undergraduate students.

At the neuronal synapse, membrane fusion is not only essential for the delivery of neurotransmitter molecules but also for the insertion of neurotransmitter receptors into the plasma membrane. Though membrane fusion involved in the delivery of neurotransmitters is well-characterized, comparatively little is known about the regulation of neurotransmitter receptor delivery.

Membrane fusion during AMPAR insertion into the plasma membrane is driven by SNARE proteins, including syntaxin-3, synaptobrevin-2, and SNAP-47 (S47). This project will investigate the role of S47, specifically focusing on its poorly characterized N-terminal and linker domains. An in vitro fusion assay will be used to describe the function of the uncharacterized S47 domains, and single-particle cryo-electron microscopy (cryoEM) will be used to solve the structure of the SNARE protein complex involved in AMPAR exocytosis.

These data will provide insight into the regulation of membrane fusion during AMPAR delivery to the plasma membrane. Additionally, an AlphaFold multimer screen of postsynaptic proteins will be combined with in vitro validation of protein-protein interactions to identify new protein regulators of AMPAR trafficking. Combined, these aims will advance our understanding of the regulation of synaptic plasticity and memory formation.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.