Analysis of behavioral asymmetries.

<p>Analysis was done in mice 3 weeks after a unilateral injection of vehicle (sham, n = 12) or 6-OHDA (lesioned, n = 18) in the MFB. Data are analysed using unpaired two-tailed t test with Welch’s correction. (<b>A)</b> Ipsilateral turns, calculated as % of the total turns t = 5.42, p < 0.0001. (<b>B)</b> Ipsilateral grooming as a % of total grooming, t = 2.60, p = 0.014. *<i>p</i>< 0.05, **** p< 0.0001.</p

Analysis of asymmetry of grooming activity.

<p>Analysis was done in mice which received a unilateral injection of 6-OHDA (A and B, lesioned, n = 8) or vehicle (C and D, sham, n = 6) into the MFB. Mice were video-recorded before the surgery, 3 weeks after the surgery in the absence of treatment (After surgery, No Trt), and 4 weeks after the surgery, between 1.5 and 3 h after the injection of 2.5 mg/kg L-DOPA and 12 mg/kg benserazide (After surgery, L-DOPA). (<b>A)</b> Ipsilateral turns, calculated as % of total turns in the lesioned mice, F_(2,21) = 10.9, p < 0.001. (<b>B)</b> Ipsilateral grooming, as a % of total grooming bouts in the lesioned animals, F_(2,14) = 4.27, p < 0.035. (<b>C)</b> Ipsilateral turns, calculated as % of total turns in the sham-operated mice, F_(2,10) = 0.56, p = 0.58. (<b>D)</b> Ipsilateral grooming, as a % of total grooming bouts in the sham-operated mice, F_(2,15) = 0.18, p = 0.83. Statistical analysis, one-way ANOVA followed by Sidak’s post-hoc tests, *p < 0.05, ***p < 0.001.</p

Effect of a Pulse of cAMP on DARPP-32 Phosphorylation

<p>Time-course of DARPP-32 isoforms after a pulse of cAMP. Brown line represents the number of cAMP molecules. Orange line represents the total number of PKA catalytic subunits not bound to regulatory subunits. DARPP-32 species are represented in black (unphosphorylated), red (D34*), blue (D75*), and green (D137*).</p

Sensitivity to the Auto-Phosphorylation Activity of CK1

<div><p>(A) Sensitivity of Thr34min to the autophosphorylation activity of CK1. The maximal values of the <i>x</i>-axis correspond to a very fast auto-inhibition of CK1, with effects identical to a Ser137Ala mutation, see red curve on <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.0020176#pcbi-0020176-g010" target="_blank">Figure 10</a>A.</p><p>(B) Sensitivity of the relaxation time after calcium signal (the “sharpness” of the response) to the autophosphorylation activity of CK1.</p></div

Effects of a Train of Ca²⁺ Spikes on DARPP-32 Phosphorylation

<p>Time-course of DARPP-32 isoforms triggered by a train of Ca²⁺ spikes. Bordeaux line represents the number of calcium ions in the dendritic spine. Colour code of DARPP-32 isoforms is the same as for <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.0020176#pcbi-0020176-g003" target="_blank">Figure 3</a>. In the absence of a cAMP signal, the phosphorylation on Thr34 remains null. (A) model A; (B) model B.</p

Dependency of the Signal Integration on the Concentration of DARPP-32

<div><p>Same simulation paradigm as the one depicted in <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.0020176#pcbi-0020176-g005" target="_blank">Figure 5</a>, but with different concentrations of DARPP-32, all the other parameters being conserved. Only D34* of model B is plotted. While the <i>x</i>-axis remains the same for all time-courses, the <i>y</i>-axis is scaled to superpose all the traces. The vertical scaling is roughly linear, that is, a 2-fold increase between successive values of DARPP-32.</p><p>(A) Calcium spikes started 50 s after the pulse of cAMP.</p><p>(B) Calcium spikes started 200 s after the pulse of cAMP.</p></div

Effect of One Pulse of cAMP Followed by a Train of Ca²⁺ Spikes on DARPP-32 Phosphorylation

<p>Time-course of DARPP-32 isoforms triggered by a pulse of cAMP followed by a train of Ca²⁺ spikes. Colour code of DARPP-32 isoforms is the same as for <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.0020176#pcbi-0020176-g003" target="_blank">Figure 3</a>. Relax and Thr34min show the two readouts used in sensitivity analysis. (A) model A; (B) model B.</p

Biochemical Model of DARPP-32 Regulation

<p>Graphical representation of the models implemented in this study. Arrow-ending lines represent transition, either phosphorylations or binding. Note that the bindings are reversible. Circle-ending lines represent enzymatic reactions. The effects of kinases and phosphatases on DARPP-32 have been represented only once for clarity, but each couple of enzymes effectively acts on every pair of arrows of the same colour. The different thicknesses of the red-arrowed lines represent the catalytic rates for the various DARPP-32 species. Dashed lines represent reactions only present in model B. Colour code of the molecular species is the same as for <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.0020176#pcbi-0020176-g001" target="_blank">Figure 1</a>.</p

Effect of the Delay between cAMP and Calcium Stimuli

<div><p>(A) Time-course of D34* in model B, triggered by a pulse of cAMP, followed, after a variable delay, by a train of Ca²⁺ spikes.</p><p>(B) Relaxation time of DARPP-32 response to calcium in function of the delay between cAMP pulse and Ca²⁺ spikes. Green diamonds represent the response of “wild-type” DARPP-32, while red triangles represent the response of a mutant without Ser137 phosphorylation.</p></div

Cross-Sensitivity to the Inhibition of PKA by DARPP-32 and the Activity of CDK5 or the Stimulation of PP2A by PKA

<div><p>Values corresponding to model A are blue, while values corresponding to model B are magenta.</p><p>(A) Cross-sensitivity to the inhibition of PKA by DARPP-32 and the activity of CDK5. Note the inverse relationship between CDK5 activity and Thr34min for strong inhibition of PKA (low kcat) while the relationship is reversed at weak inhibition.</p><p>(B) Cross-sensitivity to the inhibition of PKA by DARPP-32 and the stimulation of PP2A by PKA.</p></div