To detect the cell surface delivery of NR3B major type and insCGTT type, we performed surface immunostaining using anti-GFP antibody under non-permeabilized conditions in live cells. To confirm if this Masitinib condition allows specific detection of intracellular and extracellular pools of the protein, we first carried out immunostaining of the cells expressing GluR1 with GFP at the extracellular N-terminus and intracellular C-terminus. As predicted from the membrane topology of glutamate receptors, the staining under non-permeabilized conditions showed clear surface staining in cells expressing N-terminally GFP tagged GluR1 but not in those expressing C-terminally GFP tagged GluR1, confirming the specificity of cell surface staining. Surface staining of the cells expressing GFP-NR3B major type with anti-GFP antibody detected an irregular spotty expression pattern. This signal did not colocalize with the majority of GFP signal, indicating that the NR3B is mostly retained intracellularly and only a small proportion is delivered to the surface. This is consistent with the observation that the GFP signal was distributed almost similarly to CRT. When NR1 was coexpressed with NR3B, we saw a slight increase in cell surface NR3B, consistent with previous reports, though it did not reach statistical significance in our study. The distribution pattern of insCGTT type, both total protein detected by GFP and the cell surface protein detected by an anti-GFP antibody under non-permeabilized conditions, was similar to that of major type protein. Even though insCGTT type does not have any transmembrane domain, the surface levels of insCGTT type was*55% of the Vismodegib full-length protein. Consistently, surface expression of both NR3B major type and insCGTT type was detected using a surface biotinylation assay. ��-Tubulin, an intracellular protein, was not biotinylated, confirming the specificity of surface biotinylation. Together, these data suggest that the insCGTT type still associates with the cell membrane after it is secreted into the extracellular space. It is to be determined whether the reduced surface fraction is due to reduced export via the secretary pathway or dissociation from the cell surface. In this study, using genetic approaches, we assessed if a naturally occurring null mutant of NR3B, one of the modulatory subunits of NMDAR, has any impact on the pathogenesis of schizophrenia in the Japanese population. The variant causes a frame-shift, resulting in a truncated protein that contains the full AT-D, with homology to the bacterial periplasmic binding protein, but not the rest of the protein.