Direct interactions with G α i and G βγ mediate nongenomic signaling by estrogen receptor α .

Estrogen induces G protein-dependent nongenomic signaling in a variety of cell types via the activation of a plasma membrane-associated subpopulation of estrogen receptor alpha (ER alpha). Using pull-down experiments with purified recombinant proteins, we now demonstrate that ER alpha binds directly to G alpha i and G betagamma. Mutagenesis and the addition of blocking peptide reveals that this occurs via amino acids 251-260 and 271-595 of ER alpha, respectively.

Differentially regulated expression of endogenous RGS4 and RGS7.

Regulators of G protein signaling (RGS proteins) constitute a family of newly appreciated components of G protein-mediated signal transduction. With few exceptions, most information available on mammalian RGS proteins was gained by transfection/overexpression or in vitro experiments, with relatively little known about the endogenous counterparts. Transfection studies, typically of tagged RGS proteins, have been conducted to overcome the low natural abundance of endogenous RGS proteins.

Regulation of RGS proteins by chronic morphine in rat locus coeruleus.

The present study explored a possible role for RGS (regulators of G protein signalling) proteins in the long term actions of morphine in the locus coeruleus (LC), a brainstem region implicated in opiate physical dependence and withdrawal. Morphine influences LC neurons through activation of micro -opioid receptors, which, being Gi/o-linked, would be expected to be modulated by RGS proteins. We focused on several RGS subtypes that are known to be expressed in this brain region.

Overview of the Alliance for Cellular Signaling.

The Alliance for Cellular Signaling is a large-scale collaboration designed to answer global questions about signalling networks. Pathways will be studied intensively in two cells--B lymphocytes (the cells of the immune system) and cardiac myocytes--to facilitate quantitative modelling. One goal is to catalyse complementary research in individual laboratories; to facilitate this, all alliance data are freely available for use by the entire research community.