Hiroaki Misonou, Milena Menegola, Durga P. Mohapatra, Lauren K. Guy, Kang-Sik Park, and James S. Trimmer
Voltage-dependent K+ (Kv) channels are activated by changes in the cell membrane potential, but phosphorylation of residues in the subunits can significantly alter the extent of activation. A recent mapping of the Kv2.1 channel, a member of the Kv family present on most hippocampal and cortical pyramidal neurons, identified not one, not two, but 16 such sites. This week, Misonou et al. looked at two of these sites, S563 and S603, in more detail. The authors tested the effects of stimuli that cause increased neuronal activity such as kainate-induced seizures, or decreased neuronal activity such as deep anesthesia in rat brains in vivo. The authors also tested glutamate excitation of cultured neurons. In each case, S603 was much more sensitive. Increased neuronal activity led to calcineurin-mediated dephosphorylation, whereas reduced activity increased phosphorylation, providing a bidirectional and graded means to regulate channel function and in turn neuronal activity.
2. Development without Death
Robert R. Buss, Thomas W. Gould, Jianjun Ma, Sharon Vinsant, David Prevette, Adam Winseck, Kimberly A. Toops, James A. Hammarback, Thomas L. Smith, and Ronald W. Oppenheim
The developing nervous system of vertebrates initially generates an excess of neurons. About one-half of these neurons are then eliminated through programmed cell death, or apoptosis. Although many studies have focused on the mechanism of apoptosis and how to prevent it, few have looked at the fate of the "excess" neurons when their death was prevented. This week, Buss et al. did just that. They examined neuromuscular development in three animal models in which apoptosis was blocked: knock-out mice lacking the proapoptotic gene Bax, transgenic miceoverexpressing the survi
Contact: Sara Harris
Society for Neuroscience