Shisa7: a novel auxiliary subunit in the social network of AMPA receptors.

Most excitatory transmission in the brain is mediated by AMPA-type ionotropic glutamate receptors (AMPARs) that have a major influence in the shape of synaptic currents. Controlling the number of AMPA receptors at individual synapses is central to dynamic modifications in synaptic efficacy and plasticity. Indeed, AMPAR density is tightly regulated by basic cellular trafficking mechanisms. Thus, understanding the mechanisms by which AMPARs travel to and from synapses is a major challenge in basic neuroscience research and of fundamental importance to understand the molecular basis of synaptic plasticity and memory processes in the brain. Recently, several transmembrane proteins, termed AMPA receptor auxiliary subunits, have been shown to be intrinsic partners of the AMPA receptor complexes, critically influencing their trafficking, gating, and pharmacology. Although many efforts have been addressed to characterize the AMPA receptor auxiliary proteins so far identified, e.g. TARPs, Cornichon-2 and CKAMP44, the existence of additional auxiliary subunits remains to be explored. In this thesis work, I provide the first characterization of the effects of a new potential AMPA receptor auxiliary protein, named Shisa7, on the membrane trafficking of AMPARs in primary rat hippocampal neurons