Information transfer and storage in the nervous system occurs at synapses. Ionotropic glutamate receptors mediate the majority of excitatory signal transmission; AMPA-type glutamate-receptors (AMPARs) also centrally contribute to synaptic plasticity, a process that underlies learning. Malfunction of these receptors underlies various neurological disorders such as epilepsy and neurodegeneration. My lab is utilizing various approaches, including structural biology, cell biology, electrophysiology and super-resolution imaging to understand mechanisms underlying AMPA-R regulation and signalling at synapses.

We will be capitalising on our structural and functional data to explore regulation of synaptic AMPA-R positioning via its large N-terminal domain (NTD) (Herguedas al., 2016; Watson et al., 2017) to ultimately understand how AMPAR are slotted into synapses during synaptic plasticity/learning. This will include:

1. A combination of super-resolution microscopy (3D-STORM) and slice electrophysiology/optogenetics to study how the NTD, via interactions with synaptic proteins (Garcia-Nafria et al., 2016), including AMPA-R auxiliary subunits (Cais et al., 2014), impacts AMPAR recruitment to and clustering at synapses during plasticity.
2. Using cryo-EM (electron cryo-microscopy), we will sample the AMPAR conformational spectrum (Herguedas et al., 2016), how this is influenced by various AMPAR auxiliary proteins during the gating cycle (Greger et al.,2017). This project also seeks to study AMPAR conformations in situ, using tomographic approaches in HEK293 cells.

References

Greger, I.H. et al. (2017)
Structural and functional architecture of AMPA-type glutamate receptors and their auxiliary proteins.
Neuron 94, 713-30.

Watson et al. (2017)
Synaptic transmission and plasticity require AMPA receptor anchoring via its N-terminal domain.
eLife e23024.

Herguedas, B., García-Nafría, J., Cais, O., Fernández-Leiro, R., Krieger, J., Ho, H. and Greger. I.H. (2016)
Structure and organization of heteromeric AMPA-type glutamate receptors.
Science 352:aad3873.

García-Nafría, J., Herguedas, B., Watson, J.F. and Greger, I.H. (2016)
The dynamic AMPA receptor extracellular region: A platform for synaptic protein interactions.
J Physiol. doi: 10.1113/JP271844.

Cais O et al. (2014)
Mapping the interaction sites between AMPA receptors and TARPs reveals a role for the receptor N-terminal domain in channel gating.
Cell Reports, 9, 728-40.