| Annotated protein: | Cyclin-dependent kinase-like 5 (EC 2.7.11.22) (Serine/threonine-protein kinase 9). Gene symbol: CDKL5. Taxonomy: Homo sapiens (Human). Uniprot ID: O76039 |
| antibody wiki: | |
| SynGO gene info: | SynGO data @ CDKL5 |
| Ontology domain: | Biological Process |
| SynGO term: | regulation of postsynapse organization (GO:0099175) |
| Synapse type(s): | cerebral cortex, glutamatergic hippocampus, glutamatergic |
| Annotated paper: | Ricciardi S, et al. "CDKL5 ensures excitatory synapse stability by reinforcing NGL-1-PSD95 interaction in the postsynaptic compartment and is impaired in patient iPSC-derived neurons" Nat Cell Biol. 2012 Sep;14(9):911-23 PMID:22922712 |
| Figure(s): | Figure 2, Figure 3, Figure 6 and Supplementary Fig. S3 |
| Annotation description: | Figure 2 and Supplementary Fig. S3 CDKL5 knockdown alters spine morphology and excitatory synaptic activity. Literal: "Knockdown neurons showed a significant increase in protrusion density (Fig. 2a-i), and the dendritic protrusions were significantly thinner when compared with controls and showed a filopodia-like morphology (Fig. 2a-i). Notably, some of these thin filopodia-like spines were particularly branched and exhibited an aberrant morphology (middle and bottom panel in the top right of Fig. 2b). Furthermore, the percentage of filopodia-like spines and thin-headed spines increased, whereas the percentage of stubby and mushroom-shaped spines decreased (Fig. 2h,i). We obtained similar results forneurons infected at DIV10 and analysed at DIV15 (data not shown). Conversely, we did not score any significant alteration in dendritic arborization (data not shown). These results indicate that CDKL5 is required for ensuring a correct number of well-shaped spines." "The morphological alterations reported in CDKL5-silenced neurons were associated with a reduction in the number of excitatory synapses and synaptophysin puncta in these neurons (Fig. 2j-s)," "Consistent with the reduced excitatory synapse density, CDKL5 knockdown caused a significant decrease of mEPSCs (Fig. 2t y) but had no significant effect on inhibitory synapse density and accordingly we did not detect any significant changes in miniature inhibitory postsynaptic currents (Supplementary Fig. S3). These results indicate that CDKL5 is necessary for correct dendritic spine structure and synapse activity. Figure 3 CDKL5 knockdown impairs spine structure and excitatory synapse density in vivo. Literal: "Next, we sought to confirm the significance of our findings in vivo by electroporating embryonic day (E)13.5 embryos in utero with a plasmid containing cassettes for independent expression of sh-CDKL5#1 and EGFP. Interestingly, at E18.5, CDKL5-downregulated neurons showed a delay in radial migration. On the contrary, at P11 their relative location within the cerebral cortex was comparable to that of controls, thus indicating a transient delay in the definitive neuronal positioning (Fig. 3a,b and data not shown). Imaging of the GFP-labelled dendritic protrusions at P11, a crucial period of synaptogenesis, showed numerous protrusions with a large fraction having a well-defined head structure, characteristic of mature spines. In agreement with the in vitro studies, sh-CDKL5#1-knockdown cortical pyramidal neurons showed a robust increase in the protrusion density with significantly longer and dysmorphic dendritic protrusions (Fig. 3c-h). Next, we examined whether CDKL5 deficit might affect the number of functional excitatory synapses also in vivo. The density of VGLUT1 puncta identifying excitatory presynaptic buttons was significantly lower in sh-CDKL5#1 than in sh-control pyramidal neurons (Fig. 3e,f,i), confirming that CDKL5 is crucial for dendritic spine morphogenesis and synaptic contact maintenance in vivo." Figure 6 CDKL5-dependent phosphorylation of NGL-1 is necessary for NGL-1 PSD95 binding and correct spine morphogenesis. Literal: "Remarkably, we observed a robust reduction in the level of the NGL-1 PSD95 interaction in CDKL5-knockdown neurons (Fig. 6a). These results indicate that CDKL5 functions in promoting and/or maintaining the NGL-1-PSD95 protein association. NGL-1 phosphorylated residue Ser 631 is very close to the terminal PDZ-binding domain and therefore located at a convenient site for regulating NGL-1-PSD95 interaction. To investigate this, we transfected cells with either NGL-1 or its S631A phospho-mutant in combination with GFP-PSD95, immunoprecipitated the lysates for Myc NGL-1 and measured the amount of associated PSD95. Indeed, the phospho-mutant showed a reduced level of association with PSD95 (Fig. 6a). Next, we examined the ability of the mutant to promote synaptogenesis in hippocampal neurons. Notably, dendritic protrusions were reduced in numbers and showed a significantly elongated morphology (Fig. 6b,c). These alterations are both qualitatively and quantitatively similar to the phenotype observed in CDKL5-downregulated neurons. Therefore, it is plausible that the NGL-1S631A mutant acts through a dominant-negative effect on endogenous NGL-1 and its ability to associate with PSD95. To further strengthen this assumption, the phospho-mimetic NGL-1 mutant S631E was challenged in similar experiments. In particular, this mutant associated better with PSD95 although it was not able to significantly increase spine formation on overexpression (Fig. 6b,c). Despite that, when expressed in CDKL5-knockdown neurons, the mutant was able to restore nearly the correct length and morphology of dendritic spines, but not their numbers (Fig. 6f,g)." 8/11/2017 Pim - CDKL5 is a kinase that reglates NGL-1 PSD95 interactiono via phosphorylation and thereby regulates the morphology of the synapse. |
| Evidence tracking, Biological System: | Intact tissue Cultured neurons |
| Evidence tracking, Protein Targeting: | RNAi / shRNA Over-expression Antibody (detection) |
| Evidence tracking, Experiment Assay: | Confocal Electrophysiology (generic) IP + WB/MSMS |
| 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: | 1278 |
| Dataset release (version): | 20231201 |
| View annotation as GO-CAM model: |  |