| Annotated protein: | IQ motif and SEC7 domain-containing protein 3 (Potential synaptic guanine nucleotide exchange factor for Arf) (SynArfGEF-Po). Gene symbol: IQSEC3. Taxonomy: Rattus norvegicus (Rat). Uniprot ID: Q76M68 |
| antibody wiki: | |
| SynGO gene info: | SynGO data @ IQSEC3 |
| Ontology domain: | Biological Process |
| SynGO term: | postsynapse organization (GO:0099173) |
| Synapse type(s): | hippocampus, GABAergic |
| Annotated paper: | Um JW, et al. "IQ Motif and SEC7 Domain-containing Protein 3 (IQSEC3) Interacts with Gephyrin to Promote Inhibitory Synapse Formation" J Biol Chem. 2016 May 6;291(19):10119-30 PMID:27002143 |
| Figure(s): | Fig. 1, 2, 4, 5, 7, 8, 10 |
| Annotation description: | SynArfGEF/BRAG3/IQSEC3 is a synaptic guanine nucleotide exchange factor present in inhibitory postsynapses with the capability to activate Arf6. IQSEC3 interacts with gephrin at inhibitory synapses (Fig. 1, 2, 4) and overexpression and knock-down experiments in cultured neurons indicate that IQSEC3 is involved in the regulation of synapse development and this activity is dependent on the Arf-GEF activity of IQSEC3 (Fig. 5, 8,). The referenced paper demonstrates that IQSEC3 activates Arf6 and localizes to inhibitory synapses. 5/7/2017 Pim - SynArfGEF/BRAG3/IQSEC3 over-expression is shown to affect the number of DIV10 neuron synapses (Fig.5). Interaction of SynArfGEF/BRAG3/IQSEC3 with the postsynaptic marker protein Gephyrin is needed for this effect (Fig.7). This effect does rely on the ArfGEF activity of SynArfGEF/BRAG3/IQSEC3 (Fig.8). Fig.10 shows effect shRNA SynArfGEF/BRAG3/IQSEC3 KD on postsynaptic specialization size. Together this can be used to justify the term: "positive regulation of ARF protein signal transduction (GO:0032014)" occurs_in "postsynapse (GO:0098794)" part_of "postsynapse organization (GO:0050808)" 29/5/2018 Pim - Because SynArfGEF/BRAG3/IQSEC3 interacts with gephyrin and is essential in the postsynaptic recruitment of this protein I have annotated to the more specific term 'postsynapse organization (GO:0099173)' instead of 'synapse organization (GO:0050808)'. |
| Evidence tracking, Biological System: | Cultured neurons Non-neuronal tissue |
| Evidence tracking, Protein Targeting: | RNAi / shRNA Over-expression Antibody (detection) |
| Evidence tracking, Experiment Assay: | Confocal IP + WB/MSMS Y2H |
| Annotator(s): | Noa Lipstein (ORCID:0000-0002-0755-5899) Cordelia Imig (ORCID:0000-0001-7351-8706) Vincent O'connor (ORCID:0000-0003-3185-5709) Nils Brose (ORCID:0000-0003-0938-8534) |
| Lab: | Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany |
| Additional literature: | An Arf pull down assay was performed using a GST-GGA1 (GAT domain of Golgi-localizing gamma-adaptin ear homology domain, Arf-bindin protein 1) fusion protein. GGA1 is capable of binding GTP-bound Arfs. Co-expression of FLAG-tagged IQSEC3 and HA-tagged Arf6 in COS-7 cells caused a strong increase in the amount of GEF-bound Arf6 in comparison to cells that were transfected with Arf6-HA alone (Fig. 1a, b). Pre-embedding immuno-EM confirmed the presence of IQSEC3-immunoreactivity at postsynaptic specializations of symmetrical synapses (Fig.5). Antibodies (rabbit and guinea pig) were generated in this study using a GST-IQSEC3 fusion protein and specificity was tested by Western Blot (Fig.2) and for IHC by pre-absorption of the antigen (Fig.3b). @ PMID:21198641 |
| SynGO annotation ID: | 1052 |
| Dataset release (version): | 20231201 |
| View annotation as GO-CAM model: |  |