Figure 4.

mGluR2 activation enhances intracellular phosphorylation abundance. (A) Normalized intensity of intact phosphorylated C-terminal tails over 1 mM l-glutamic acid treatment (0–60 min). The intensity for a given phosphorylated stoichiometry is normalized to the intensity of the unmodified mGluR2 tail in the corresponding LC–MS run. Values for each phosphoform are denoted by color. Values for the monophosphorylated population are shown in light blue, the diphosphorylated population is shown in dark blue, the triphosphorylated population is shown in green, and the tetraphosphorylated population is shown in gold. (B) Each phosphorylated stoichiometry is provided as an individual inset. Error bars represent the standard error of the mean (N = 3 biological replicates and 3 technical replicates). Brackets indicate a statistical comparison between two data points using a Wilcoxon–Mann–Whitney test. Significant differences are denoted as follows: * = p < 0.05, ** = p ≤ 0.01, *** = p ≤ 0.001, **** = p ≤ 0.0001.