RESUMO
Suicide is defined as the action of harming oneself with the intention of dying. It is estimated that worldwide, one person dies by suicide every 40 s, making it a major health problem. Studies in families have suggested that suicide has a genetic component, so the search for genetic variants associated with suicidal behavior could be useful as potential biomarkers to identify people at risk of suicide. In Mexico, some studies of gene variants related to neurotransmission and other important pathways have been carried out and potential association of variants located in the following genes has been suggested: SLC6A4, SAT-1, TPH-2, ANKK1, GSHR, SCARA50, RGS10, STK33, COMT, and FKBP5. This systematic review shows the genetic studies conducted on the Mexican population. This article contributes by compiling the existing information on genetic variants and genes associated with suicidal behavior, in the future could be used as potential biomarkers to identify people at risk of suicide.
Assuntos
Proteínas RGS , Suicídio , Humanos , México/epidemiologia , Ideação Suicida , Biomarcadores , Proteínas da Membrana Plasmática de Transporte de Serotonina , Proteínas Serina-Treonina QuinasesRESUMO
Plant survival depends on adaptive mechanisms that constantly rely on signal recognition and transduction. The predominant class of signal discriminators is receptor kinases, with a vast member composition in plants. The transduction of signals occurs in part by a simple repertoire of heterotrimeric G proteins, with a core composed of α-, ß-, and γ-subunits, together with a 7-transmembrane Regulator G Signaling (RGS) protein. With a small repertoire of G proteins in plants, phosphorylation by receptor kinases is critical in regulating the active state of the G-protein complex. This review describes the in vivo detected phosphosites in plant G proteins and conservation scores, and their in vitro corresponding kinases. Furthermore, recently described outcomes, including novel arrestin-like internalization of RGS and a non-canonical phosphorylation switching mechanism that drives G-protein plasticity, are discussed.
Assuntos
Proteínas de Arabidopsis , Arabidopsis , Proteínas Heterotriméricas de Ligação ao GTP , Proteínas RGS , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Subunidades alfa de Proteínas de Ligação ao GTP/metabolismo , Proteínas Heterotriméricas de Ligação ao GTP/metabolismo , Fosforilação , Fosfotransferases/metabolismo , Proteínas de Plantas/metabolismo , Plantas/metabolismo , Proteínas RGS/genética , Proteínas RGS/metabolismoRESUMO
G protein-coupled receptors kinase 2 (GRK2) plays a major role in receptor regulation and, as a consequence, in cell biology and physiology. GRK2-mediated receptor desensitization is performed by its kinase domain, which exerts receptor phosphorylation promoting G protein uncoupling and the cessation of signaling, and by its RGS homology (RH) domain, able to interrupt G protein signaling. Since GRK2 activity is exacerbated in several pathologies, many efforts to develop inhibitors have been conducted. Most of them were directed toward GRK2 kinase activity and showed encouraging results on in vitro systems and animal models. Nevertheless, limitations including unspecific effects or pharmacokinetics issues prevented them from advancing to clinical trials. Surprisingly, even though the RH domain demonstrated the ability to desensitize GPCRs, this domain has been less explored. Herein, we show in vitro activity of a series of compounds that, by inhibiting GRK2 RH domain, increase receptor cAMP response, avoid GRK2 translocation to the plasma membrane, inhibit coimmunoprecipitation of GRK2 with Gαs subunit of heterotrimeric G protein, and prevent receptor desensitization. Also, we preliminarily evaluated candidates' ADMET properties and observed suitable lipophilicity and cytotoxicity. These novel inhibitors of phosphorylation-independent actions of GRK2 might be useful in elucidating other RH domain roles and lay the foundation for the development of innovative pharmacologic therapy for diseases where GRK2 activity is exacerbated.
Assuntos
AMP Cíclico/metabolismo , Quinase 2 de Receptor Acoplado a Proteína G/antagonistas & inibidores , Linhagem Celular Tumoral , Desenvolvimento de Medicamentos , Quinase 2 de Receptor Acoplado a Proteína G/metabolismo , Células HEK293 , Humanos , Fosforilação , Domínios Proteicos/efeitos dos fármacos , Proteínas RGS/metabolismo , Transdução de Sinais/efeitos dos fármacosRESUMO
The aim of this study was to characterize the morphological properties of amorphous silica nanoparticles (SiO2 NPs), their cytotoxicity and intracellular location within Human Osteoblasts (HOB). Additionally, SiO2 NPs were explored for their effectivity as carriers of CRTC3-siRNA on Human Preadipocytes (HPAd), and thus downregulate RGS2 gene expression. SiO2 NPs were synthesized using the method of Stöber at 45 °C, 56 °C, and 62 °C. These were characterized via TEM with EDS, Zeta Potential and FT-IR. Cytotoxicity was evaluated by XTT at three concentrations 50, 100 and 500 µg/mL; SiO2 NPs intracellular localization was observed through Confocal Laser Scanning Microscope. Delivering siRNA effectivity was measured by RT-qPCR. Morphology of SiO2 NPs was spherical with a range size from 64 to 119 nm; their surface charge was negative. Confocal images demonstrated that SiO2 NPs were located within cellular cytoplasm. At a SiO2 NPs concentration of 500 µg/mL HOB viability decreased, while at 50 µg/mL and 100 µg/mL cell viability was not affected regardless SiO2 NPs size. SiO2 NPs-CRTC3-siRNA are effective to down-regulate RGS2 gene expression in HPAd without cytotoxic effects. The developed SiO2 NPs-CRTC3-siRNA are a promising tool as a delivery vehicle to control obesity.
Assuntos
Nanopartículas/química , Proteínas RGS/metabolismo , RNA Interferente Pequeno/metabolismo , Dióxido de Silício/química , Fatores de Transcrição/farmacologia , Antineoplásicos/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Regulação para Baixo , Sistemas de Liberação de Medicamentos , Técnicas de Silenciamento de Genes , Humanos , Microscopia Confocal , Osteoblastos , Tamanho da Partícula , Proteínas RGS/genética , Espectroscopia de Infravermelho com Transformada de Fourier , Fatores de Transcrição/genéticaRESUMO
G protein-coupled receptors are critical mediators of platelet activation whose signaling can be modulated by members of the regulator of G protein signaling (RGS) family. The 2 most abundant RGS proteins in human and mouse platelets are RGS10 and RGS18. While each has been studied individually, critical questions remain about the overall impact of this mode of regulation in platelets. Here, we report that mice missing both proteins show reduced platelet survival and a 40% decrease in platelet count that can be partially reversed with aspirin and a P2Y12 antagonist. Their platelets have increased basal (TREM)-like transcript-1 expression, a leftward shift in the dose/response for a thrombin receptor-activating peptide, an increased maximum response to adenosine 5'-diphosphate and TxA2, and a greatly exaggerated response to penetrating injuries in vivo. Neither of the individual knockouts displays this constellation of findings. RGS10-/- platelets have an enhanced response to agonists in vitro, but platelet count and survival are normal. RGS18-/- mice have a 15% reduction in platelet count that is not affected by antiplatelet agents, nearly normal responses to platelet agonists, and normal platelet survival. Megakaryocyte number and ploidy are normal in all 3 mouse lines, but platelet recovery from severe acute thrombocytopenia is slower in RGS18-/- and RGS10-/-18-/- mice. Collectively, these results show that RGS10 and RGS18 have complementary roles in platelets. Removing both at the same time discloses the extent to which this regulatory mechanism normally controls platelet reactivity in vivo, modulates the hemostatic response to injury, promotes platelet production, and prolongs platelet survival.
Assuntos
Plaquetas/metabolismo , Ativação Plaquetária/genética , Proteínas RGS/genética , Trombopoese/genética , Animais , Plaquetas/efeitos dos fármacos , Sobrevivência Celular/genética , Camundongos , Camundongos Knockout , Fosforilação , Fator de Ativação de Plaquetas/farmacologia , Ativação Plaquetária/efeitos dos fármacos , Inibidores da Agregação Plaquetária/farmacologia , Contagem de Plaquetas , Proteínas RGS/metabolismo , Trombopoese/efeitos dos fármacosRESUMO
BACKGROUND: Evidence suggests that liability for suicide behavior is heritable; additionally, suicide has been partly related to other psychiatric disorders. Nevertheless, most of the information reported so far address Caucasian and Asian individuals. Hence, our aim was to conduct a gene-level association study in Mexican psychiatric individuals diagnosed with suicide attempt. METHODS: We recruited 192 individuals from two clinical centers in Mexico. All participants were born in Mexico and had Mexican parents and grandparents. Direct genotyping was performed using the commercial platform Infinium PsychArray BeadChip. A p-value lower than 1e-05 was considered as gene-level significant and a p-value lower than 1e-04 was considered as gene-level nominal significant. RESULTS: Our analyses showed that SCARA5 was associated to suicide intent at a gene-level with statistical significance (p-value = 1.12e-6). Other genes were nominally associated with suicide attempt: GHSR (p-value = 0.0004), RGS10 (p-value = 5.13e-5), and STK33 (p-value = 3.62e-5). Regarding gene variant analyses, the SNPs with a statistical association (p > .05) were rs561361616, rs1537577, rs11198999 for RGS10, and rs11041981, rs11041993, rs11041994, rs11041995, rs11041997, rs10840083, rs10769918 for STK33. For these genes, previous studies have associated SCARA5 with depression, GHSR with alcohol dependence and depression, and RGS10 with schizophrenia and depression. To date, STK33 has not been associated with any psychiatric disorder. CONCLUSION: Our outcomes revealed that SCARA5, GHSR, RGS10 and STK33 could be considered as risk biomarkers for suicide attempt behavior in our Mexican psychiatric sample. We recommend to perform larger scale analyses to have conclusive results.
Assuntos
Estudo de Associação Genômica Ampla/métodos , Polimorfismo de Nucleotídeo Único , Tentativa de Suicídio/estatística & dados numéricos , Adulto , Predisposição Genética para Doença , Humanos , México/epidemiologia , Pessoa de Meia-Idade , Proteínas Serina-Treonina Quinases/genética , Proteínas RGS/genética , Receptores de Grelina/genética , Receptores Depuradores Classe A/genética , Tentativa de Suicídio/psicologia , Adulto JovemRESUMO
Saccharomyces cerevisiae mitoribosomes are specialized in the translation of a few number of highly hydrophobic membrane proteins, components of the oxidative phosphorylation system. Mitochondrial characteristics, such as the membrane system and its redox state driven mitoribosomes evolution through great diversion from their bacterial and cytosolic counterparts. Therefore, mitoribosome presents a considerable number of mitochondrial-specific proteins, as well as new protein extensions. In this work we characterize temperature sensitive mutants of the subunit bL34 present in the 54S large subunit. Although bL34 has bacterial homologs, in yeast it has a long 65 aminoacids mitochondrial N-terminal addressing sequence, here we demonstrate that it can be replaced by the mitochondrial addressing sequence of Neurospora crassa ATP9 gene. The bL34 temperature sensitive mutants present lowered translation of mitochondrial COX1 and COX3, which resulted in reduced cytochrome c oxidase activity and respiratory growth deficiency. The sedimentation properties of bL34 in sucrose gradients suggest that similarly to its bacterial homolog, bL34 is also a later participant in the process of mitoribosome biogenesis.
Assuntos
Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Mitocôndrias/metabolismo , Ribossomos Mitocondriais/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Sequência de Aminoácidos , Complexo IV da Cadeia de Transporte de Elétrons/genética , Mitocôndrias/genética , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Mutagênese Sítio-Dirigida , Biossíntese de Proteínas , Proteínas RGS/genética , Proteínas RGS/metabolismo , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Alinhamento de SequênciaRESUMO
BACKGROUND: Understanding the molecular basis underlying the formation of bone-forming osteocytes and lipid-storing adipocytes will help provide insights into the cause of disorders originating in stem/progenitor cells and develop therapeutic treatments for bone- or adipose-related diseases. In this study, the role of RGS2 and RGS4, two members of the regulators of G protein signaling (RGS) family, was investigated during adipogenenic and osteogenenic differentiation of human mesenchymal stem cells (hMSCs). RESULTS: Expression of RGS2 and RGS4 were found to be inversely regulated during adipogenesis induced by dexamethasone (DEX) and 3-isobutyl-methylxanthine, regardless if insulin was present, with RGS2 up-regulated and RGS4 down-regulated in response to adipogenic induction. RGS2 expression was also up-regulated during osteogenesis at a level similar to that induced by treatment of DEX alone, a shared component of adipogenic and osteogenic differentiation inducing media, but significantly lower than the level induced by adipogenic inducing media. RGS4 expression was down-regulated during the first 48 h of osteogenesis but up-regulated afterwards, in both cases at levels similar to that induced by DEX alone. Expression knock-down using small interfering RNA against RGS2 resulted in decreased differentiation efficiency during both adipogenesis and osteogenesis. On the other hand, expression knock-down of RGS4 also resulted in decreased adipogenic differentiation but increased osteogenic differentiation. CONCLUSIONS: RGS2 and RGS4 are differentially regulated during adipogenic and osteogenic differentiation of hMSCs. In addition, both RGS2 and RGS4 play positive roles during adipogenesis but opposing roles during osteogenesis, with RGS2 as a positive regulator and RGS4 as a negative regulator. These results imply that members of RGS proteins may play multifaceted roles during human adipogenesis and osteogenesis to balance or counterbalance each other's function during those processes.
Assuntos
Adipogenia/fisiologia , Regulação da Expressão Gênica/fisiologia , Células-Tronco Mesenquimais/citologia , Osteócitos/citologia , Osteogênese/fisiologia , Proteínas RGS/metabolismo , Adipogenia/genética , Regulação da Expressão Gênica/genética , Humanos , Osteogênese/genética , Proteínas RGS/genética , Fatores de TempoRESUMO
BACKGROUND: Understanding the molecular basis underlying the formation of bone-forming osteocytes and lipid-storing adipocytes will help provide insights into the cause of disorders originating in stem/progenitor cells and develop therapeutic treatments for bone- or adipose-related diseases. In this study, the role of RGS2 and RGS4, two members of the regulators of G protein signaling (RGS) family, was investigated during adipogenenic and osteogenenic differentiation of human mesenchymal stem cells (hMSCs). RESULTS: Expression of RGS2 and RGS4 were found to be inversely regulated during adipogenesis induced by dexamethasone (DEX) and 3-isobutyl-methylxanthine, regardless if insulin was present, with RGS2 up-regulated and RGS4 down-regulated in response to adipogenic induction. RGS2 expression was also up-regulated during osteogenesis at a level similar to that induced by treatment of DEX alone, a shared component of adipogenic and osteogenic differentiation inducing media, but significantly lower than the level induced by adipogenic inducing media. RGS4 expression was down-regulated during the first 48 h of osteogenesis but up-regulated afterwards, in both cases at levels similar to that induced by DEX alone. Expression knock-down using small interfering RNA against RGS2 resulted in decreased differentiation efficiency during both adipogenesis and osteogenesis. On the other hand, expression knock-down of RGS4 also resulted in decreased adipogenic differentiation but increased osteogenic differentiation. CONCLUSIONS: RGS2 and RGS4 are differentially regulated during adipogenic and osteogenic differentiation of hMSCs. In addition, both RGS2 and RGS4 play positive roles during adipogenesis but opposing roles during osteogenesis, with RGS2 as a positive regulator and RGS4 as a negative regulator. These results imply that members of RGS proteins may play multifaceted roles during human adipogenesis and osteogenesis to balance or counterbalance each other's function during those processes.
Assuntos
Humanos , Osteócitos/citologia , Osteogênese/fisiologia , Regulação da Expressão Gênica/fisiologia , Proteínas RGS/metabolismo , Adipogenia/fisiologia , Células-Tronco Mesenquimais/citologia , Osteogênese/genética , Fatores de Tempo , Regulação da Expressão Gênica/genética , Proteínas RGS/genética , Adipogenia/genéticaRESUMO
According to receptor theory, the effect of a ligand depends on the amount of agonist-receptor complex. Therefore, changes in receptor abundance should have quantitative effects. However, the response to pheromone in Saccharomyces cerevisiae is robust (unaltered) to increases or reductions in the abundance of the G-protein-coupled receptor (GPCR), Ste2, responding instead to the fraction of occupied receptor. We found experimentally that this robustness originates during G-protein activation. We developed a complete mathematical model of this step, which suggested the ability to compute fractional occupancy depends on the physical interaction between the inhibitory regulator of G-protein signaling (RGS), Sst2, and the receptor. Accordingly, replacing Sst2 by the heterologous hsRGS4, incapable of interacting with the receptor, abolished robustness. Conversely, forcing hsRGS4:Ste2 interaction restored robustness. Taken together with other results of our work, we conclude that this GPCR pathway computes fractional occupancy because ligand-bound GPCR-RGS complexes stimulate signaling while unoccupied complexes actively inhibit it. In eukaryotes, many RGSs bind to specific GPCRs, suggesting these complexes with opposing activities also detect fraction occupancy by a ratiometric measurement. Such complexes operate as push-pull devices, which we have recently described.