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. Author manuscript; available in PMC: 2008 Jan 23.
Published in final edited form as: Brain Res Mol Brain Res. 2005 Apr 27;135(1-2):1–11. doi: 10.1016/j.molbrainres.2004.10.045

Figure 5. Effects of single mutations in PKA phosphorylation sites on regulation of coupling by PKA.

Figure 5

Neurobiotin tracer coupling was measured using the scrape-loading technique in HeLa cells stably transfected with Cx35 or phosphorylation-deficient Cx35 mutants. Treatments with the PKA activator Sp-8-cpt-cAMPS (designated Sp) and the PKA inhibitor Rp-8-cpt-cAMPS (designated Rp) were the same as in figure 1. Data shown are normalized to the no drug condition (cntrl) for each cell line examined, and data for Cx35 wild type are the same as in figure 1H. The single mutations Ser110Ala or Ser276Ala significantly reduced the effect of the PKA activator, and prevented the effect of the PKA inhibitor. In the truncation mutant, Ser298ter, the PKA activator increased coupling and the PKA inhibitor decreased coupling. Data shown are means of 14 to 39 independent measurements; error bars are +1 SEM. Significance at the p<0.05 level (using a t-test) is shown by *; significance at the p<0.01 level is shown by **.