The researchers characterized the main AMPA receptors (AMPARs) in the pig cerebellum using mass spectrometry, cryo-electron microscopy and electrophysiology.[1] They identified calcium-impermeable GluA2/A4 heteromers with four TARP subunits that are predominantly of neuronal origin.[1] They further discovered calcium-permeable GluA1/A4 heteromers specific for Bergmann glia containing two Type-2 TARP subunits.[1] GluA4 receptors display compact N-terminal domains that support their synaptic transport.[1] The study defines the organizing principles of AMPAR-TARP complexes in the mammalian cerebellum and reveals how different receptor subtypes support cell type-specific functions.[1][3] These findings provide insight into the composition of AMPARs subunits in the cerebellum.[4]