ISSN:
1471-4159
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
Abstract: NG108-15 cells were exposed in culture to 1 μM [d-Ala2, d-Leu5]enkaphalin (DADLE) for 17 h. This treatment increased the maximum iloprost- and 5′-(N-ethylcarboxamido)adenosine-dependent activation of adenylate cyclase, as well as basal enzyme activity. In addition, there was an increase in the capacity of 5′-guanylylimidodiphosphate [Gpp(NH)p] to inhibit adenylate cyclase activity by direct interaction with the α-subunit of the Gi regulatory protein. A similar effect was observed if the cells were exposed to 10 μM carbachol. These treatments of NG108-15 cells did not alter the capacity of NaF to activate adenylate cyclase by direct interaction with Gsα. Exposure of NG108-15 cells to DADLE alone or DADLE plus carbachol had no effect on the capacity of pertussis toxin to ADP-ribosylate membrane proteins in these cells; neither was there any change in the activity of eukaryotic ADP-ribosyltransferase expressed in these cells. Under these conditions, the endogenous enzyme did not label any protein with a molecular mass similar to Giα, 41 kDa. Treatment of the cells with DADLE or carbachol had no effect on the abundance of Gsα, Giα, or Gβ. The underlying mechanism for the changes in agonist-dependent stimulatory responses or Gpp(NH)p-dependent inhibition of adenylate cyclase remains obscure, but appears not to be mediated by eukaryotic ADP-ribosyltransferase activity or a change in the abundance of G proteins known to regulate adenylate cyclase.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1471-4159.1992.tb09772.x
Permalink