Signal transduction by G protein-coupled receptors. Bioenergetics and G protein activation: Proton transfer and GTP synthesis to explain the experimental findings.

G protein-coupled receptors and G proteins play a key role in transmembrane signalling. Theories regarding biogenetics describe the mechanisms by which the energy made available by the oxidation of substrates, or by the asbsorption of light, is used for energy-consuming reactions such as ATP synthesis. This report joins biogenetics with signal transduction via G protein-coupled receptors by reviewing the bioenergetic mechanisms and G protein activation processes, and by offering interpretations of well-established theories. The purpose of these interpretations is to explain all experimental findings, to stimulate a series of experiments and to contribute to the understanding of the molecular mechanisms underlying transmembrane signalling.