Abstract
Ionotropic glutamate receptors (iGluRs) are tetrameric ligand-gated cation channels that mediate excitatory signal transmission in the central nervous system (CNS) of vertebrates. The members of the iGluR subfamily of α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors (AMPARs) mediate most of the fast excitatory signal transmission, and their abundance in the postsynaptic membrane is a major determinant of the strength of excitatory synapses. Therefore, regulation of AMPAR trafficking to the postsynaptic membrane is an important constituent of mechanisms involved in learning and memory formation, such as long-term potentiation (LTP) and long-term depression (LTD). Auxiliary subunits play a critical role in the facilitation and regulation of AMPAR trafficking and function. The currently identified auxiliary subunits of AMPARs are transmembrane AMPA receptor regulatory proteins (TARPs), suppressor of lurcher (SOL), cornichon homologues (CNIHs), synapse differentiation-induced gene I (SynDIG I), cysteine-knot AMPAR modulating proteins 44 (CKAMP44), and germ cell-specific gene 1-like (GSG1L) protein. In this review we summarize our current knowledge of the modulatory influence exerted by these important but still underappreciated proteins.
Highlights
The family of Ionotropic glutamate receptors (iGluRs) consists of 18 different subunits found in mammals which are categorized into four subfamilies based on pharmacological properties, biological function, and sequence homology
We focus on auxiliary subunits of AMPARs: highly specialized, non-transient binding partners that—besides their role in receptor trafficking— modulate pharmacological and electrophysiological properties of AMPARs
transmembrane AMPA receptor regulatory proteins (TARPs) and cornichon homologues (CNIHs) directly interact with the AMPARs, starting immediately after translation in the ER or at least after early maturation, i.e., final modification of their glycosylation and receptor assembly
Summary
The family of iGluRs consists of 18 different subunits found in mammals which are categorized into four subfamilies based on pharmacological properties, biological function, and sequence homology. LTD, the opposite process, leads to the endocytosis of AMPARs and to a reduced number of AMPARs at the PSD [1] On their way from the ER to the PSD, AMPARs interact temporarily, either directly or indirectly, with various proteins, including chaperones, stabilizers, mediators of vesicular delivery, and anchoring proteins. These interacting proteins, which include for example GRIP1, KIF1A, KIF5, Rab, Liprin-α, NEEP21, GRASP-1, Rab, and Stx, and their functions in trafficking pathways of AMPARs have recently been reviewed by Anggono and Huganir and are not described here [2]. We focus on auxiliary subunits of AMPARs: highly specialized, non-transient binding partners that—besides their role in receptor trafficking— modulate pharmacological and electrophysiological properties of AMPARs
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
