Annotated protein:Complement C1q subcomponent subunit C. Gene symbol: C1QC. Taxonomy: Mus musculus (Mouse). Uniprot ID: Q02105
antibody wiki:
SynGO gene info:SynGO data @ C1QC
Ontology domain:Cellular Component
SynGO term:extrinsic component of postsynaptic membrane (GO:0098890)
Synapse type(s):hippocampus, glutamatergic
Annotated paper:Stephan AH, et al. "A dramatic increase of C1q protein in the CNS during normal aging" J Neurosci. 2013 Aug 14;33(33):13460-74 PMID:23946404
Figure(s):Figure 6
Annotation description:Figure 6i-k: "Using cryo-immuno electron microscopy, we found that C1q protein was localized to and near to the surfaces of presynaptic and postsynaptic structures"

"Dual-immunogold analysis in the dentate gyrus molecular layer of aged mice. C1q immunoreactivity (12 nm gold particles, arrows) was detected in close proximity to both presynaptic (green) and postsynaptic (brown) elements. In contrast, synaptophysin immunoreactivity (6 nm gold particles, white arrowheads) was detected inside clearly identifiable presynaptic terminals as well as associated with unidentifiable structures, likely reflecting presynaptic terminals"
Evidence tracking, Biological System:Intact tissue
Evidence tracking, Protein Targeting:Antibody (detection)
Evidence tracking, Experiment Assay:Electron Microscopy
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
Additional literature:Authors confirmed the synaptic presence of all complement C1q subcomponent subunits (A/B/C) in pulldowns of Neuronal pentraxin-1 (NPTX1/NP1) and C1qA from cortical synaptosomes.

Figure 3: synaptosomes that were fluorescently immunolabeled for C1q and NP1/2 sorted together (FACS), suggesting C1q is exclusively present on the surface of NP1/2 positive synaptosomes.

Figure 4: confocal imaging of cerebral cortical sections that were immunofluorescence labeled for C1q, synaptophysin (SYP) and NP1/2 (NPTX1/2) showed partial co-localization. @ PMID:33628204

confocal immunostaining with antibodies to C1q and synaptic markers showed localization at mostly presynapse but also at the postsynapse. Synaptosome sorting and super-resolution microscopy further confirmed synaptic C1q localization. @ PMID:29844190

confocal immunostaining with antibodies to C1q and synaptic markers showed localization at both pre- and post-synapse @ PMID:18083105

confocal immunostaining with antibodies to C1q and PSD95 (DLG4) showed localization at postsynapses @ PMID:27033548
SynGO annotation ID:5489
Dataset release (version):20231201
View annotation as GO-CAM model:Gene Ontology