Nicotine Enhances the Cyclic AMP-Dependent Protein Kinase-Mediated Phosphorylation of α4 Subunits of Neuronal Nicotinic Receptors
Article first published online: 18 NOV 2002
Journal of Neurochemistry
Volume 69, Issue 6, pages 2427–2431, December 1997
How to Cite
Hsu, Y.-N., Edwards, S. C. and Wecker, L. (1997), Nicotine Enhances the Cyclic AMP-Dependent Protein Kinase-Mediated Phosphorylation of α4 Subunits of Neuronal Nicotinic Receptors. Journal of Neurochemistry, 69: 2427–2431. doi: 10.1046/j.1471-4159.1997.69062427.x
- Issue published online: 18 NOV 2002
- Article first published online: 18 NOV 2002
- Resubmitted manuscript received August 1, 1997; accepted August 1, 1997.
- Neuronal nicotinic receptor;
- Xenopus oocytes;
- Cyclic AMP-dependent protein kinase;
Abstract: Studies determined whether α4β2 or α3β2 neuronal nicotinic receptors expressed in Xenopus oocytes are substrates for cyclic AMP-dependent protein kinase (PKA) and whether nicotine affects receptor phosphorylation. The cRNAs for the subunits were coinjected into oocytes, and cells were incubated for 24 h in the absence or presence of nicotine (50 nM for α4β2 and 500 nM for α3β2 receptors). Nicotine did not interfere with the isolation of the receptors. When receptors isolated from oocytes expressing α4β2 receptors were incubated with [γ-32P]ATP and the catalytic subunit of PKA, separated by electrophoresis, and visualized by autoradiography, a labeled phosphoprotein with the predicted molecular size of the α4 subunit was present. Phosphorylation of α4 subunits of α4β2 receptors increased within the first 5 min of incubation with nicotine and persisted for 24 h. In contrast, receptors isolated from oocytes expressing α3β2 receptors did not exhibit a labeled phosphoprotein corresponding to the size of the α3 subunit. Results suggest that the PKA-mediated phosphorylation of α4 and not α3 subunits may explain the differential inactivation by nicotine of these receptors subtypes expressed in oocytes.