| Annotated protein: | Protein turtle homolog B (Immunoglobulin superfamily member 9B). Gene symbol: IGSF9B. Taxonomy: Rattus norvegicus (Rat). Uniprot ID: D3ZB51 |
| antibody wiki: | |
| SynGO gene info: | SynGO data @ IGSF9B |
| Ontology domain: | Cellular Component |
| SynGO term: | postsynaptic specialization of symmetric synapse (GO:0099629) |
| Synapse type(s): | hippocampus, GABAergic cerebral cortex, GABAergic |
| Annotated paper: | Woo J, et al. "The adhesion protein IgSF9b is coupled to neuroligin 2 via S-SCAM to promote inhibitory synapse development" J Cell Biol. 2013 Jun 10;201(6):929-44 PMID:23751499 |
| Figure(s): | Fig 1; Fig 2 F; Fig 6; Fig 8 C |
| Annotation description: | Fig 1. IgSF9b is express in GABAergic interneurons and mainly localized at inhibitory synapses. Literal: "IgSF9b clusters colocalized with the vesicular GABA transporter (VGAT; an inhibitory presynaptic protein) in pyramidal neurons (Fig. 1 C) and in interneurons (Fig. 1 D). IgSF9b also colocalized with gephyrin, an inhibitory postsynaptic protein, and the alfa1 subunit of GABAA receptors in interneurons (Fig. 1, E and F). In contrast, IgSF9b minimally colocalized with the vesicular glutamate transporter vGlut1 and Shank (excitatory pre- and postsynaptic proteins, respectively) in interneurons (Fig. 1 G). In quantitative analysis, about 78% of IgSF9b puncta colocalized with GAD67 (n = 20). In cultured cortical neurons, IgSF9b displayed distribution patterns similar to those observed in hippocampal neurons, being more abundant in GAD65-positive GABAergic interneurons (Fig. 1 H), and being mainly present at inhibitory synapses (Fig. 1, I and J). IgSF9b colocalized with gephyrin but not with PSD-95 in interneurons (Fig. 1, K and L). These results indicate that IgSF9b mainly localizes to inhibitory synapses." Fig 2 F. IgSF9b in enriched in the PSD fractions within crude synaptosomes together with the gamma2 subunit of GABAA receptors Literal: "Within crude synaptosomes, IgSF9b was highly enriched in postsynaptic density (PSD) fractions, being detected in PSD III, the most detergent-resistant PSD fraction (Fig. 2 F). This extent of PSD enrichment is comparable to that of PSD-95, an excitatory postsynaptic scaffolding protein tightly associated with the PSD. Notably, the gamma2 subunit of GABAA receptors was also highly detected in PSD III, whereas neuroligin 2 and the alfa1 subunit of GABAA receptors were enriched up to PSD II. These results suggest that IgSF9b, together with the gamma2 subunit of GABAA receptors, is tightly associated with inhibitory synapses." Fig 6. IgSF9b and gephyrin/GABAA receptors localize to distinct subsynaptic domains at inhibitory synapses. Literal: "To further explore this at a higher resolution, we used super-resolution immunofluorescence imaging using the two color stochastic optical reconstruction microscopy (STORM) method, which provides a resolution up to 10 times higher than that of regular immunofluorescence imaging and has been successful in revealing subsynaptic localization of synaptic proteins (Bates et al., 2007; Dani et al., 2010). This approach revealed that IgSF9b and gephyrin localize to distinct subsynaptic domains at inhibitory synapses in cultured hippocampal neurons (Fig. 6 A). Similarly, IgSF9b and the gamma2 subunit of GABAA receptors showed distinct distribution patterns at inhibitory synapses (Fig. 6 B). In contrast, gephyrin and the gamma2 subunit of GABAA receptors showed substantially overlapping distribution patterns (Fig. 6 C)." Fig 8 C. IgSF9b colocalizes with MAGI and neuroligin 2 proteins, but not with PSD-95, in cultured hippocampal interneurons. Literal: "In addition, IgSF9b colocalized with both MAGI proteins and neuroligin 2, but not with PSD-95, in cultured interneurons (Fig. 8 C). These results suggest that IgSF9b forms a ternary complex with S-SCAM and neuroligin 2 at inhibitory synapses." |
| Evidence tracking, Biological System: | Intact tissue Cultured neurons |
| Evidence tracking, Protein Targeting: | Antibody (detection) |
| Evidence tracking, Experiment Assay: | Confocal Western blot Biochemical fractionation (generic) |
| Annotator(s): | Chiara Verpelli (ORCID:0000-0003-2949-9725) Carlo Sala (ORCID:0000-0003-0662-9523) |
| Lab: | CNR Neuroscience Institute Milan and Dept. of Biotechnology and Translational Medicine, University of Milan, 20129 Milan, Italy |
| SynGO annotation ID: | 2412 |
| Dataset release (version): | 20231201 |
| View annotation as GO-CAM model: |  |