Regulation of the Stoichiometry of Protein Components of the Stimulatory Adenylyl Cyclase Cascade

Abstract

Rapid progress has been made in methods to transgenically alter levels of signal-transducing polypetides in mice, in a tissue-specific manner in most of the cases. These studies can be invisaged to presage the use of such strategies in human gene therapy, and, thus, it is clearly of vital importance that simpler systems be developed in parallel to allow examination of how transgenic modification of the flux through signal transduction cascades might be modified by regulation of expression of levels of receptors, G-proteins, and effector enzymes. Furthermore, such systems would be particularly amenable to test many aspects of classical pharmacological receptor theory as to how ligand potency and efficacy might alter with designed manipulation of signaling cassette stoichiometry. Based on both the endogenous expression of a considerable variety of receptors that regulate adenylyl cyclase activity and the elegant studies on potential compartmentalization of receptors that all mediate inhibition of adenylyl cyclase in these cells, the study described in this chapter selected the neuroblastoma × glioma hybrid cell line, NG108-15, as the parental host for a series of studies in which levels of each of a G s α -coupled receptor, G s α , and adenylyl cyclase are systematically altered. These studies have provided new insights into the regulation of the stimulatory adenylyl cyclase cascade.