Skip to main content
. Author manuscript; available in PMC: 2015 Mar 5.
Published in final edited form as: Neuron. 2014 Mar 5;81(5):1070–1083. doi: 10.1016/j.neuron.2014.01.022

Figure 1. Cdk5 phosphorylates the NR2B subunit of the NMDAR at Ser1116 and regulates its cell surface expression.

Figure 1

(A) Schematic of NR2B indicating domains and motifs. (B) Positive identification of serine residue 1116 of NR2B as a Cdk5 substrate by LC MS/MS analysis of phosphopeptides immunoprecipitated with phospho-Cdk substrate antibody. (C) Time-dependent Ser1116 NR2B phosphorylation (P-S1116) by Cdk5 in vitro detected by quantitative immunoblottng. Quantitated values were normalized to total NR2B levels. (D) Dose-dependent reduction of P-S1116 in hippocampal slices incubated with the Cdk5 inhibitor, CP681301 (n = 4; *p < 0.05, **p < 0.01, ***p < 0.001; ANOVA). (E) Quantitative immunoblot analysis of P-S1116 and total NR2B in hippocampal lysates from Cdk5 cKO and WT mice (n = 4). Loss of Cdk5 in cKO is also shown (bottom panel). (F) Inhibition of Cdk5 increases NR2B cell surface levels in hippocampal neurons. Top panels show immunofluorescence staining of cell surface GFP-NR2B (green) and post-synaptic, intra-neuronal Homer-1 (red) in hippocampal neurons treated with vehicle (control) or the Cdk5 inhibitor CP681301. Bottom panels depict high magnification of stained dendrites. (G) Quantification of cell surface GFP-NR2B fluorescence within dendritic processes (n = 22–26 cells). Data are represented as mean ± SEM. See also Figure S1.