Annotated protein:Phosphatidylinositol 3-kinase catalytic subunit type 3 (PI3-kinase type 3) (PI3K type 3) (PtdIns-3-kinase type 3) (EC 2.7.1.137) (Phosphoinositide-3-kinase class 3). Gene symbol: PIK3C3. Taxonomy: Mus musculus (Mouse). Uniprot ID: Q6PF93
antibody wiki:
SynGO gene info:SynGO data @ PIK3C3
Ontology domain:Cellular Component
SynGO term:postsynaptic endosome (GO:0098845)
Synapse type(s):hippocampus, glutamatergic
hippocampus, GABAergic
Annotated paper:Liu GT, et al. "Endosomal phosphatidylinositol 3-phosphate controls synaptic vesicle cycling and neurotransmission" EMBO J. 2022 May 2;41(9):e109352 PMID:35318705
Figure(s):Figure 1, S1
Annotation description:"PI(3)P-containing endosomes were detected throughout neuronal somata and neurites including pre- and postsynaptic compartments immunopositive for the SV-associated protein Synapsin and postsynaptic Homer, respectively (Fig 1A and B). Further analysis by confocal microscopy imaging revealed similar levels of PI(3)P at excitatory synapses marked by the vesicular glutamate transporter 1 (vGLUT1) and at inhibitory synapses identified by the vesicular GABA transporter vGAT (Fig 1C and D). These data show that PI(3)P-containing endosomes are present at both excitatory and inhibitory synapses, consistent with their presumed roles in synapse physiology and neurotransmission."

As a control, selective inhibition of VPS34 by the well-established specific small molecule inhibitor VPS34IN1 (Bago et al, 2014, PMID:25177796; Ketel et al, 2016, PMID:26760201) effectively reduced somatic and synaptic PI(3)P to nearly undetectable levels (Figure S1).

note; endosomal localization of PI3P was inferred by authors;
"In most cell types, endosomes are marked by high levels of phosphatidylinositol 3-phosphate [PI(3)P], a signaling lipid that is crucial for endosome function (Di Paolo & De Camilli, 2006, PMID:17035995; Balla, 2013, PMID:23899561; Raiborg et al, 2013, PMID:23289851)."
Evidence tracking, Biological System:Cultured neurons
Evidence tracking, Protein Targeting:Over-expression
Evidence tracking, Experiment Assay:Super resolution
Confocal
Annotator(s):Frank Koopmans (ORCID:0000-0002-4973-5732)
Guus Smit (ORCID:0000-0002-2286-1587)
Matthijs Verhage (ORCID:0000-0002-2514-0216)
Lab:Department of Functional Genomics, Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands
SynGO annotation ID:4735
Dataset release (version):20231201
View annotation as GO-CAM model:Gene Ontology