| Annotated protein: | SH3 and multiple ankyrin repeat domains protein 1 (Shank1). Gene symbol: SHANK1. Taxonomy: Mus musculus (Mouse). Uniprot ID: D3YZU1 |
| antibody wiki: | |
| SynGO gene info: | SynGO data @ SHANK1 |
| Ontology domain: | Biological Process |
| SynGO term: | modulation of chemical synaptic transmission (GO:0050804) |
| Synapse type(s): | hippocampus, glutamatergic Schaffer collateral synapse (CA3->CA1) |
| Annotated paper: | Hung AY, et al. "Smaller dendritic spines, weaker synaptic transmission, but enhanced spatial learning in mice lacking Shank1" J Neurosci. 2008 Feb 13;28(7):1697-708 PMID:18272690 |
| Figure(s): | Figure 2, figure 3 B and C, figure 4, figure 5 |
| Annotation description: | Figure 2. Altered composition of PSD fractions in Shank1 mutant mice. Literal: "One-dimensional SDSPAGE (Fig. 2A) and two-dimensional gel electrophoresis (data not shown) of purified PSDs revealed no obvious change in the overall protein patterns. By immunoblotting, the Shank1-specific 1356 antibody confirmed the absence of Shank1 protein in the PSD fraction of Shank1 knock-out brains (Fig. 2B, top left). The pan-Shank 3856 antibody showed aprox 40% reduction in total Shank immunoreactivity in PSDs from Shank1-/- mice (Fig. 2B,C). Interestingly, the aprox 240 kDa Shank1 protein is more prominent in the PSD preparation compared with crude membrane extracts [compare "Shank (total)" in Figs. 1E, 2B], suggesting that Shank1 may be more highly enriched in the PSD than Shank2/3. A variety of glutamate receptors, scaffold proteins, and signaling molecules were measured by quantitative immunoblotting (Fig. 2B,C). In Shank1-mutant PSDs, there was a significant reduction of GKAP (aprox 30%). In addition, the level of Homer1b/c showed a modest but significant decrease (aprox 20%). Thus, the levels of two scaffold/adaptor proteins that bind directly to Shank were reduced in Shank1-deficient PSDs. In the same preparations, we detected no significant difference in the abundance of many other proteins that are known to be associated with synapses or the PSD, including NMDA, AMPA, and metabotropic glutamate receptors PSD-95 and GRIP (Fig. 2B,C). Also unchanged were the PSD levels of β-PIX and cortactin, actin regulatory proteins that can interact directly with Shank but that are not highly enriched in the PSD (Naisbitt et al., 1999; Park et al., 2003). Figure 3B, C. Altered immunostaining of PSD proteins in Shank1-deficient neurons Literal: "We then performed immunocytochemistry to examine the distribution of synaptic proteins in dissociated hippocampal neurons cultured from individual wild-type or Shank1-/- mouse embryos." "In line with the biochemical results, there was also a significant decrease in the density of GKAP puncta in Shank1-deficient neurons (Fig. 3B,C)." Figure 4. Smaller dendritic spines and thinner PSDs in Shank1 mutant mice. To examine the in vivo role of Shank1 in spine morphology, we performed blinded quantitative analysis of the number and size of dendritic spines in adult wild-type and Shank1-/- mice (Fig. 4A). We focused on apical dendrites of CA1 pyramidal neurons of hippocampus, where synapse morphology and plasticity have been studied extensively. Mean spine density showed a slight decrease in Shank1 knock-out mice (Fig. 4B). Cumulative frequency plots of spine length (Fig. 4C) and spine head width (Fig. 4D) revealed a highly significant shift toward smaller spine size. Although the absolute differences are small, possibly related to the presence of the remaining Shank isoforms, these data affirm that Shank1 is important for spine growth or maintenance in vivo." "We next examined the ultrastructure of synapses, analyzing thin-section electron microscopic (EM) micrographs from wild-type and Shank1-/- mouse brains (Fig. 4E). In hippocampal CA1 region, the mean PSD thickness of Shank1-/- synapses was significantly reduced relative to wild type, and cumulative frequency graphs revealed a roughly parallel shift across the range of PSD thickness (Fig. 4G). However, the cumulative frequency distribution showed that Shank1 mutant synapses suffered primarily a loss of the largest PSDs relative to wild type (Fig. 4F). Indeed, PSD length among the largest quartile of CA1 synapses measured per animal was significantly decreased in Shank1 mutants. These data suggest that although Shank1 is not required for synapse formation, it may be critical for the development and/or maintenance of the largest subset of PSDs and synapses in particular." Figure 5. Decreased synaptic strength in Shank1 mutant mice. Literal: " We investigated excitatory synaptic transmission at the Schaffer collateral/commissural-CA1 synapse in acute hippocampal slices from wild-type and Shank1-/- mice (3-5 weeks of age). First, we examined synaptic transmission in Shank1-/- mice by measuring AMPA receptor-mediated field EPSPs in the stratum radiatum using extracellular recording techniques (Fig. 5A). The input- output curve for Shank1-/- mice was significantly shifted downward compared with wild type, especially at high stimulus intensities, demonstrating that Shank1 deficiency reduces basal synaptic transmission." "we examined the amplitudes and frequencies of the AMPARmediated mEPSCs (Fig. 5B). There was no significant difference in the average mEPSC amplitude between wild-type and Shank1-/- mice. However, the frequency of the mEPSC from Shank1-/- mutants was significantly reduced, suggesting that decreased basal transmission is primarily caused by a reduction in the number of functional synapses." |
| Evidence tracking, Biological System: | Intact tissue Cultured neurons |
| Evidence tracking, Protein Targeting: | Genetic transformation (eg; knockout, knockin, mutations) |
| Evidence tracking, Experiment Assay: | Electron Microscopy Confocal Electrophysiology (generic) 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: | 3682 |
| Dataset release (version): | 20231201 |
| View annotation as GO-CAM model: |  |