G protein beta gamma subunits synthesized in Sf9 cells. Functional characterization and the significance of prenylation of gamma

Heterotrimeric guanine nucleotide-binding regulatory proteins (G proteins) consist of a nucleotide-binding alpha subunit and a high- affinity complex of beta and gamma subunits. There is molecular heterogeneity of beta and gamma, but the significance of this diversity is poorly understood. Different G protein beta and gamma subunits have been expressed both singly and in combinations in Sf9 cells. Although expression of individual subunits is achieved in all cases, beta gamma subunit activity (support of pertussis toxin-catalyzed ADP-ribosylation of rGi alpha 1) is detected only when beta and gamma are expressed concurrently. Of the six combinations of beta gamma tested (beta 1 or beta 2 with gamma 1, gamma 2, or gamma 3), only one, beta 2 gamma 1, failed to generate a functional complex. Each of the other five complexes has been purified by subunit exchange chromatography using Go alpha-agarose as the chromatographic matrix. We have detected differences in the abilities of the purified proteins to support ADP- ribosylation of Gi alpha 1; these differences are attributable to the gamma component of the complex. When assayed for their ability to inhibit calmodulin-stimulated type-I adenylylcyclase activity or to potentiate Gs alpha-stimulated type-II adenylylcyclase, recombinant beta 1 gamma 1 and transducin beta gamma are approximately 10 and 20 times less potent, respectively, than the other complexes examined. Prenylation and/or further carboxyl-terminal processing of gamma are not required for assembly of the beta gamma subunit complex but are indispensable for high affinity interactions of beta gamma with either G protein alpha subunits or adenylylcyclases

Post-transcriptional regulation and subcellular localization of G-protein γ7 subunit: implications for striatal function and behavioral responses to cocaine

The striatal D1 dopamine receptor (D1R) and A2a adenosine receptor (A2aR) signaling pathways play important roles in drug-related behaviors. These receptors activate the Golf protein comprised of a specific combination of αolfβ2γ7 subunits. During assembly, the γ7 subunit sets the cellular level of the Golf protein. In turn, the amount of Golf protein determines the collective output from both D1R and A2aR signaling pathways. This study shows the Gng7 gene encodes multiple γ7 transcripts differing only in their non-coding regions. In striatum, Transcript 1 is the predominant isoform. Preferentially expressed in the neuropil, Transcript 1 is localized in dendrites where it undergoes post-transcriptional regulation mediated by regulatory elements in its 3′ untranslated region that contribute to translational suppression of the γ7 protein. Earlier studies on gene-targeted mice demonstrated loss of γ7 protein disrupts assembly of the Golf protein. In the current study, morphological analysis reveals the loss of the Golf protein is associated with altered dendritic morphology of medium spiny neurons. Finally, behavioral analysis of conditional knockout mice with cell-specific deletion of the γ7 protein in distinct populations of medium spiny neurons reveals differential roles of the Golf protein in mediating behavioral responses to cocaine. Altogether, these findings provide a better understanding of the regulation of γ7 protein expression, its impact on Golf function, and point to a new potential target and mechanisms for treating addiction and related disorders

Temporal Trends and Geographic Variations in Mortality Rates from Prescription Opioids: Lessons from Florida and West Virginia

OBJECTIVES: To explore temporal trends and geographic variations in mortality from prescription opioids from 1999 to 2016. METHODS: Centers for Disease Control and Prevention Wide-ranging Online Data for Epidemiologic Research Multiple Cause of Death files were used to calculate age-adjusted rates and 95% confidence intervals (CIs) and create spatial cluster maps. RESULTS: From 1999 to 2016, counties in West Virginia experienced the highest overall mortality rates in the United States from prescription opioids. Specifically, from 1999 to 2004, the highest rate in West Virginia of 24.87/100,000 (95% CI 17.84-33.73) was the fourth highest in the United States. From 2005 to 2009, West Virginia experienced the highest rate in the United States, 60.72/100,000 (95% CI 47.33-76.71). From 2010 to 2016, West Virginia also experienced the highest rate in the United States, which was 90.24/100,000 (95% CI 73.11-107.36). As such, overall, West Virginia experienced the highest rates in the United States and the largest increases overall of ~3.6-fold between 1999 and 2004 and 2010 and 2016. From 1999 to 2004, Florida had no hot spots, but from 2006 to 2010 they did appear, and from 2011 to 2016, they disappeared. CONCLUSIONS: These data show markedly divergent temporal trends and geographic variations in mortality rates from prescription opioids, especially in the southern United States. Specifically, although initial rates were high and continued to increase alarmingly in West Virginia, they increased but then decreased in Florida. These descriptive data generate hypotheses requiring testing in analytic epidemiological studies. Understanding the divergent patterns of prescription opioid-related deaths, especially in West Virginia and Florida, may have important clinical and policy implications

Temporal Trends and Geographic Variations in Mortality Rates From Tobacco and Firearms in the United States

We explored temporal trends and geographic variations in United States of America (US) mortality rates from smoking and firearms from 1999 to 2019. To do so, we used the publicly available Centers for Disease Control and Prevention (CDC) Wide Ranging Online Data for Epidemiologic Research (WONDER) with Multiple Cause of Death files from 1999 to 2019. Using age-specific rates and ArcGIS Pro Advanced software for Optimized Hot Spot Analyses from Esri, we generated maps of statistically significant spatial clusters with 90-99% confidence intervals with the Getis-Ord Gi* statistic for mortality from smoking-related causes and firearms. These data show temporal trends and geographic variations in mortality from smoking and firearms in the US. Smoking and firearm-related mortality from assault and suicide increased throughout the US and clustered in the Southeast. Firearm-related suicide also clustered in the continental West and Alaska. These descriptive data generate many hypotheses which are testable in analytic epidemiologic studies designed a priori to do so. The trends suggest smoking and firearm-related causes pose particular challenges to the Southeast and firearms also to the West and Alaska. These data may aid clinicians and public health authorities to implement evidence-based smoking avoidance and cessation programs as well as address firearm mortality, with particular attention to the areas of highest risks. As has been the case with cigarettes, individual behavior changes as well as societal changes are likely to be needed to achieve decreases in premature mortality

Computational Modeling for the Activation Cycle of G-proteins by G-protein-coupled Receptors

In this paper, we survey five different computational modeling methods. For comparison, we use the activation cycle of G-proteins that regulate cellular signaling events downstream of G-protein-coupled receptors (GPCRs) as a driving example. Starting from an existing Ordinary Differential Equations (ODEs) model, we implement the G-protein cycle in the stochastic Pi-calculus using SPiM, as Petri-nets using Cell Illustrator, in the Kappa Language using Cellucidate, and in Bio-PEPA using the Bio-PEPA eclipse plug in. We also provide a high-level notation to abstract away from communication primitives that may be unfamiliar to the average biologist, and we show how to translate high-level programs into stochastic Pi-calculus processes and chemical reactions.Comment: In Proceedings MeCBIC 2010, arXiv:1011.005

Effect of calcium and cAMP on G_oα expression in neonatal rat cardiac myocytes

Culturing neonatal rat cardiac myocytes in 50 mM KCl inhibits the accumulation of Go that occurs when myocytes are placed in culture. The mechanism by which high extracellular K+ inhibits Go accumulation in myocytes was investigated by measurement of the concentration of intracellular Ca2+ ([Ca2+]) and adenosine 3',5'-cyclic monophosphate concentration ([cAMP]) of control and K+-depolarized myocytes. Although intracellular [Ca2++] in K+-depolarized myocytes was twofold higher than basal intracellular [Ca2+] in control cells, the mean intracellular [Ca2+] in contracting control myocytes was comparable to that of K+-depolarized myocytes. Furthermore, myocytes cultured in low Ca2+ plus high K+ exhibited an inhibition of Go accumulation, even though intracellular [Ca2+] was 10-fold lower than that of cells cultured in normal Ca2+ plus high K+. In addition, intracellular [cAMP] of K+-depolarized myocytes was comparable to that of control cells. Moreover, dibutyryl cAMP inhibited Go accumulation in myocytes to the same extent as high K+, even though intracellular [cAMP] differed 10-fold. Thus neither intracellular Ca2+ nor cAMP appear to mediate the inhibitory effect of high K+ on Go accumulation. However, cAMP has an inhibitory effect on Goα expression that is independent of K+. dibutyryl cAMP; fura-2; immunoblotting </jats:p