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GRASP1 ubiquitination regulates AMPA receptor surface expression and synaptic activity in cultured hippocampal neurons
Author(s) -
Mele Miranda,
De Luca Pasqualino,
Santos Ana Rita,
Vieira Marta,
Salazar Ivan L.,
Pinheiro Paulo S.,
Duarte Carlos B.
Publication year - 2021
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.201903061rr
Subject(s) - ampa receptor , microbiology and biotechnology , ubiquitin , postsynaptic potential , silent synapse , hek 293 cells , glutamate receptor , receptor , hippocampal formation , transfection , chemistry , postsynaptic density , ubiquitin ligase , biology , biochemistry , neuroscience , gene
The synaptic expression of glutamate receptors of the α‐amino‐3‐hydroxy‐5‐methylisoxazole‐4‐propionic acid (AMPA) type is dynamically controlled by interaction with binding partners and auxiliary proteins. These proteins can be regulated by posttranslational modifications, including ubiquitination. In this work, we investigated the regulation of glutamate receptor interacting protein‐associated protein 1 (GRASP1) by ubiquitin‐dependent mechanisms and its impact on surface expression and activity of synaptic AMPA receptors. Cotransfection of GFP‐ubiquitin decreased myc‐GRASP1 protein levels in HEK293T cells, and this effect was inhibited upon transfection of an ubiquitin mutant that cannot be ubiquitinated on Lys48. In addition, transfection of cultured hippocampal neurons with GFP‐ubiquitin reduced the dendritic levels of endogenous GRASP1 and decreased the surface expression of GluA1 AMPA receptor subunits, an effect that was partly reversed by cotransfection with GRASP1. Similarly, transfection of hippocampal neurons with GFP‐ubiquitin decreased the amplitude of miniature excitatory postsynaptic currents (mEPSCs) mediated by Ca 2+ ‐impermeable AMPA receptors, and this effect was abrogated by cotransfection of GRASP1. Together, the results show a role for ubiquitination in the regulation of the postsynaptic protein GRASP1, which has an impact on the surface distribution of AMPA receptors and on their activity at the synapse.