Document Type

Article

Publication Title

Molecular Cell

Publication Date

8-22-2013

Volume

51

Issue

4

Disciplines

Biology | Life Sciences

Abstract

Heterotrimeric G proteins are cytoplasmic transducers of signals generated by ligandactivated 7-transmembrane receptors (G protein-coupled receptors, or GPCRs) embedded in the plasma membranes of cells. GPCRs activate G proteins by catalyzing exchange of GDP for GTP at the alpha subunit (Gα) with the concomitant release of the Gβγ heterodimer. Separately or together Gα•GTP and Gβγ stimulate enzymes that produce second messengers (e.g. cyclic AMP), control ion channels, Ras-family G proteins and regulate transcription (Cabrera-Vera et al., 2003). In yeast, GPCRs intercept mating pheromones and monitor extracellular glucose concentration, and so generate intracellular signals either to arrest growth or to proliferate. In this issue, Isom et al. show that Gpa1, the Gα subunit involved in the mating pheromone response, is also regulated by intracellular pH, reaffirming a growing recognition that protons, like other mono- and divalent cations, have roles as cellular second messengers (Isom et al., 2013). The path to this discovery began with the structural problem, how proteins can accommodate buried ionizable amino acid side chains in their interiors, and now arrives at a better understanding of the mechanisms by which regulatory proteins evolve properties as transducers of proton-mediated signaling.

DOI

10.1016/j.molcel.2013.08.012

Rights

© 2013 Elsevier Inc.

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