Journal article
Self-activating G protein α subunits engage seven-transmembrane Regulator of G protein Signaling (RGS) proteins and a Rho guanine nucleotide exchange factor effector in the amoeba Naegleria fowleri
The Journal of biological chemistry, Vol.298(8), 102167
06/20/2022
DOI: 10.1016/j.jbc.2022.102167
PMCID: PMC9283941
PMID: 35738399
Abstract
The free-living amoeba Naegleria fowleri is a causative agent of primary amoebic meningoencephalitis and is highly resistant to current therapies, resulting in mortality rates >97%. As many therapeutics target G protein-centered signal transduction pathways, further understanding the functional significance of G protein signaling within N. fowleri should aid future drug discovery against this pathogen. Here, we report that the N. fowleri genome encodes numerous transcribed G protein signaling components, including G protein-coupled receptors (GPCRs), heterotrimeric G protein subunits, Regulator of G protein Signaling (RGS) proteins, and candidate Gα effector proteins. We found N. fowleri Gα subunits have diverse nucleotide cycling kinetics; Nf Gα5 and Gα7 exhibit more rapid nucleotide exchange than GTP hydrolysis (i.e. “self-activating” behavior). A crystal structure of Nf Gα7 highlights the stability of its nucleotide-free state, consistent with its rapid nucleotide exchange. Variations in the phosphate binding loop (P-loop) also contribute to nucleotide cycling differences among Gα subunits. Similar to plant G protein signaling pathways, N. fowleri Gα subunits selectively engage members of a large seven-transmembrane RGS protein family, resulting in acceleration of GTP hydrolysis. We show Nf Gα2 and Gα3 directly interact with a candidate Gα effector protein, RGS-RhoGEF, similar to mammalian Gα12/13 signaling pathways. We demonstrate Nf Gα2 and Gα3 each engage RGS-RhoGEF through a canonical Gα/RGS domain interface, suggesting a shared evolutionary origin with G protein signaling in the enteric pathogen Entamoeba histolytica. These findings further illuminate the evolution of G protein signaling and identify potential targets of pharmacological manipulation in Naegleria fowleri.
Details
- Title: Subtitle
- Self-activating G protein α subunits engage seven-transmembrane Regulator of G protein Signaling (RGS) proteins and a Rho guanine nucleotide exchange factor effector in the amoeba Naegleria fowleri
- Creators
- Dustin E. Bosch - Department of Pathology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242William R. Jeck - Duke University School of MedicineDavid P. Siderovski - Department of Pharmacology & Neuroscience, University of North Texas Health Science Center, Fort Worth, TX 76107
- Resource Type
- Journal article
- Publication Details
- The Journal of biological chemistry, Vol.298(8), 102167
- DOI
- 10.1016/j.jbc.2022.102167
- PMID
- 35738399
- PMCID
- PMC9283941
- NLM abbreviation
- J Biol Chem
- ISSN
- 0021-9258
- eISSN
- 1083-351X
- Publisher
- Elsevier Inc
- Grant note
- DOI: 10.13039/100006808, name: University of North Carolina; DOI: 10.13039/100000002, name: National Institutes of Health; DOI: 10.13039/100000026, name: National Institute on Drug Abuse, award: R01DA048153; DOI: 10.13039/100000060, name: National Institute of Allergy and Infectious Diseases, award: K08AI159619
- Language
- English
- Date published
- 06/20/2022
- Academic Unit
- Pathology
- Record Identifier
- 9984269059602771
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