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Gloriam, D.

Publications and source records attributed to Gloriam, D..

2 recordsLinked to original sources
bioRxiv2021

GPCR-G protein selectivity - a unified meta-analysis

Two-thirds of human hormones and one-third of clinical drugs act on membrane receptors that couple to G proteins to achieve appropriate functional responses. While G protein transducers from literature are annotated in the Guide to Pharmacology database, two recent large-scale datasets now expand the receptor-G protein couplome. However, these three datasets differ in scope and reported G protein couplings giving different coverage and conclusions on GPCR-G protein signaling. Here, we report a common coupling map uncovering novel couplings supported by both large-scale studies, the selectivity/promiscuity of GPCRs and G proteins, and how the co-coupling and co-expression of G proteins compare to the families from phylogenetic relationships. The coupling map and insights on GPCR-G protein selectivity will catalyze advances in receptor research and cellular signaling towards the exploitation of G protein signaling bias in design of safer drugs.

pharmacology and toxicology↗
bioRxiv2021

Molecular determinants underlying DS2 activity at δ-containing GABAA receptors

Delta selective compound 2 (DS2) is one of the most widely used tools to study selective actions mediated by {delta} subunit-containing GABAA receptors. DS2 was discovered over 10 years ago, but despite great efforts, the precise molecular site of action has remained elusive. Using a combination of computational modeling, site-directed mutagenesis and cell-based pharmacological assays, we probed three potential binding sites for DS2 and analogs at 4{beta}1{delta} receptors: an 4(+){delta}(-) interface site in the extracellular domain (ECD), equivalent to the diazepam binding site in {beta}{gamma}2 receptors, and two sites in the transmembrane domain (TMD); one in the 4(+){beta}1(-) and one in the 4(-){beta}1(+) interface, with the 4(-){beta}1(+) site corresponding to the binding site for etomidate and a recently disclosed low-affinity binding site for diazepam. We show that mutations in the ECD site did not abrogate DS2 modulation. However, mutations in the TMD 4(+){beta}1(-) interface, either 4(S303L) of the 4(+)-side or {beta}1(I289Q) of the {beta}1(-)-side, convincingly disrupted the positive allosteric modulation by DS2. This was consistently demonstrated both in an assay measuring membrane potential changes and by whole-cell patchclamp electrophysiology and rationalized by docking studies. Importantly, general sensitivity to modulators was not compromised in the mutated receptors. This study sheds important light on the long-sought molecular recognition site for DS2, refutes the misconception that the selectivity of DS2 for {delta}-containing receptors is caused by a direct interaction with the {delta}-subunit, and instead points towards a functional selectivity of DS2 and its analogs via a surprisingly well-conserved binding pocket in the TMD. Significance statement{delta}-Containing GABAA receptors represent potential drug targets for the treatment of several neurological conditions with aberrant tonic inhibition. Yet, no drugs are currently in clinical use. With the identification of the molecular determinants responsible for positive modulation by the know compound DS2, the ground is laid for design of ligands that selectively target {delta}-containing GABAA receptor subtypes, for better understanding of tonic inhibition, and, ultimately, for rational development of novel drugs.

pharmacology and toxicology↗