1. Measuring the Dynamics of PKA Signaling
Nicolas Gervasi, Rgine Hepp, Ludovic Tricoire, Jin Zhang, Bertrand Lambolez, Danile Paupardin-Tritsch, and Pierre Vincent
Subcellular compartmentalization of cAMP-dependent protein kinase A (PKA) determines which substrates are phosphorylated at the membrane, cytosol, and nucleus. This week, Gervasi et al. chose two reporters to examine these signaling microdomains in thalamic neurons in brain slices. To monitor PKA in the nucleus and cytosol, the authors virally expressed the AKAR2 protein, which contains a PKA substrate domain, a phosphothreonine binding domain, and two fluorophores. Fluorescence resonance energy transfer efficacy, which increases with conformational changes in AKAR2, was used to monitor PKA-dependent phosphorylation. To monitor PKA at the membrane, they used the calcium-activated potassium channels that underlie the slow afterhyperpolarization as a physiological reporter. Increases in PKA with 5-HT7 receptor activation or direct stimulation of adenylyl cyclase with forskolin reduced the slow afterhyperpolarization potential current within 30 s. However, activation of 5-HT7 receptors had a smaller and slower effect than forskolin on cytosolic AKAR2 and nuclear effects were slower still, reaching a maximum after 17 min.
2. Stress and Neurogenesis in the Rat
Rosanne M. Thomas, Gregory Hotsenpiller, and Daniel A. Peterson
We are all familiar with the immediate effects of acute psychosocial stress on our mood. Now a report from Thomas et al. this week addresses the impact of such an acute stress on new neurons in the hippocampus. To induce stress, the authors introduced a naive male intruder into an established rat colony, a maneuver that caused the dominant male resident to approach, pin down, and bite at the newcomer. The authors treated the rescued intruder with thymidine analogs at various time points relative to the stress
Contact: Sara Harris
Society for Neuroscience