Lee Shekter - Selective G-protein regulation of neuronal calcium channels.

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      Publication Details (including relevant citation   information): Toth,P.T., Shekter,L.R., Ma,G.H.,   Philipson,L.H., Miller,R.J., J Neurosci,   1996, 16 (15), pp 4617-4624

      Abstract: We examined the properties and   regulation of Ca channels resulting from the expression of human   alpha1B and alpha1E subunits stably expressed in KEK293 cells.   The ancillary subunits beta1B and alpha2/delta were also stably   expressed in these cell lines. Ca currents in alpha1B-expressing   cells had the properties of N-type currents. Ca currents in cells   expressing alpha1E exhibited a novel profile that was similar to   the properties of the "R type" Ca current. Introduction of   GTP-gamma-S into alpha1B cells greatly enhanced the extent of   prepulse facilitation of the Ca current, whereas it had only a   very small effect in alpha1E-expressing cells. Activation of   somatostatin receptors endogenous to HEK293 cells or kappa opioid   receptors, expressed in the cells after transfection, inhibited   Ca currents in alpha1B-expressing cells. This inhibition was   blocked by pertussis toxin and was partially relieved by a   depolarizing prepulse. In contrast, no inhibitory effects were   noted in cells expressing alpha1E channels under the same   circumstances. HEK293 cells normally contained G-proteins from   all of the four major families. Inhibition of Ca currents by   kappa agonists in alpha1B-expressing cells was enhanced slightly   by the cotransfection of several G-protein alpha subunits. kappa   agonists, however, had no effect in alpha1E-containing cells,   even after overexpression of different G-protein alpha-subunits.   In summary, these results demonstrate that there is a large   difference in the susceptibility of alpha1B- and alpha1E-based Ca   channels to regulation by G-proteins. This is so despite the fact   that the two types of Ca channels show substantial similarities   in their primary sequences.

      Address (URL): http://www.hubmed.org/display.cgi?uids=8764650