Fig. 2

Two GluN2A protein bands are observed in human but not mouse brain. a Topology of the GluN2A subunit of the NMDA receptor and of GluN2A-S predicted from human mRNA studies. A spliced region is retained in canonical GluN2A leading to an alteration of the reading frame to generate a diverging C-terminal sequence (red) with early truncation. Epitopes for the antibodies used are shown in green and are numbered. b Immunoblots with specific antibodies against the canonical GluN2A and putative GluN2A-S protein in human and mouse cortical lysates. c GluN2A proteins were pulled down with an N-terminal antibody. Band 2 was cut from Coomassie-stained polyacrylamide gel and analysed by mass spectrometry. IP, immunoprecipitate. FT, flowthrough d A set of 14 peptides were confirmed to be present in this band. Figure shows tryptic peptides from band 2 coverage to either canonical GluN2A amino acid sequence (Uniprot: Q12879) or GluN2AS (Q12879–2, predicted) confirming band 2 contains GluN2A protein. e Homogenate from freshly frozen cortical human tissue probed with the GluN2A antibody Abcam 133,265 (select blots shown on top) and quantification of GluN2A-S / GluN2A immunoreactivity (bottom). See Table 1 for human tissue sample details. f Recombinant GluN2A-S co-expressed with GluN1 in HEK293 cells produces functional NMDARs as demonstrated by a typical J-shaped curve in response to 40 mM NMDA in response to a slow ramp of voltage (− 70 to + 50 mV, 3 s)