RESUMO
Mitochondria are cellular powerhouses that generate energy through the electron transport chain (ETC). The mitochondrial genome (mtDNA) encodes essential ETC proteins in a compartmentalized manner, however, the mechanism underlying metabolic regulation of mtDNA function remains unknown. Here, we report that expression of tricarboxylic acid cycle enzyme succinate-CoA ligase SUCLG1 strongly correlates with ETC genes across various TCGA cancer transcriptomes. Mechanistically, SUCLG1 restricts succinyl-CoA levels to suppress the succinylation of mitochondrial RNA polymerase (POLRMT). Lysine 622 succinylation disrupts the interaction of POLRMT with mtDNA and mitochondrial transcription factors. SUCLG1-mediated POLRMT hyposuccinylation maintains mtDNA transcription, mitochondrial biogenesis, and leukemia cell proliferation. Specifically, leukemia-promoting FMS-like tyrosine kinase 3 (FLT3) mutations modulate nuclear transcription and upregulate SUCLG1 expression to reduce succinyl-CoA and POLRMT succinylation, resulting in enhanced mitobiogenesis. In line, genetic depletion of POLRMT or SUCLG1 significantly delays disease progression in mouse and humanized leukemia models. Importantly, succinyl-CoA level and POLRMT succinylation are downregulated in FLT3-mutated clinical leukemia samples, linking enhanced mitobiogenesis to cancer progression. Together, SUCLG1 connects succinyl-CoA with POLRMT succinylation to modulate mitochondrial function and cancer development.
Assuntos
Biogênese de Organelas , Succinato-CoA Ligases , Animais , Humanos , Camundongos , Acil Coenzima A/metabolismo , Acil Coenzima A/genética , Linhagem Celular Tumoral , Proliferação de Células , Progressão da Doença , DNA Mitocondrial/metabolismo , DNA Mitocondrial/genética , RNA Polimerases Dirigidas por DNA/metabolismo , RNA Polimerases Dirigidas por DNA/genética , Leucemia/metabolismo , Leucemia/genética , Leucemia/patologia , Mitocôndrias/metabolismo , Mitocôndrias/genética , Proteínas Mitocondriais/metabolismo , Proteínas Mitocondriais/genética , Succinato-CoA Ligases/metabolismo , Succinato-CoA Ligases/genéticaRESUMO
The Succinate-CoA ligase (SUCL1) gene family is involved in energy metabolism, phytohormone signaling, and plant growth, development, and tolerance to stress. This is the first study to analyze the SUCL1 gene family in wheat (Triticum aestivum). 17 TaSUCL1 genes were identified in the complete genome sequence and classified into five subfamilies based on related genes found in three other species. The 17 TaSUCL1 genes were unevenly distributed across 11 chromosomes, and the collinearity of these genes was further investigated. Through using real-time qPCR (RT-qPCR) analysis, we identified the expression patterns of the TaSUCL1 genes under various tissues and different heavy metal stress conditions. The functions of selected TaSUCL1-1 gene were investigated by RNA interference (RNAi). This study provided a comprehensive analysis of the TaSUCL1 gene family. Within the TaSUCL1 genes, the exon-intron structure and motif composition exhibited significant similarity among members of the same evolutionary branch. Homology analysis and phylogenetic comparison of the SUCL1 genes in different plants offered valuable insights for studying the evolutionary characteristics of the SUCL1 genes. The expression levels of the TaSUCL1 genes in different tissues and under various metal stress conditions reveal its important role in plant growth and development. Gene function analysis demonstrated that TaSUCL1-1 silenced wheat plants exhibited a decrease in the total cadmium (Cd) concentrations and gene expression levels compared to the wild type (WT). Additionally, TaSUCL1-1 belonging to class c physically interacts with the ß-amylase protein TaBMY1 as verified by yeast two-hybridization. This research provides a useful resource for further study of the function and molecular genetic mechanism of the SUCL1 gene family members.
Assuntos
Cádmio , Regulação da Expressão Gênica de Plantas , Família Multigênica , Filogenia , Proteínas de Plantas , Succinato-CoA Ligases , Triticum , Triticum/genética , Triticum/metabolismo , Cádmio/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Succinato-CoA Ligases/genética , Succinato-CoA Ligases/metabolismo , Estresse Fisiológico/genética , Cromossomos de Plantas/genéticaRESUMO
Lysine succinylation is a subtype of protein acylation associated with metabolic regulation of succinyl-CoA in the tricarboxylic acid cycle. Deficiency of succinyl-CoA synthetase (SCS), the tricarboxylic acid cycle enzyme catalyzing the interconversion of succinyl-CoA to succinate, results in mitochondrial encephalomyopathy in humans. This report presents a conditional forebrain-specific knockout (KO) mouse model of Sucla2, the gene encoding the ATP-specific beta isoform of SCS, resulting in postnatal deficiency of the entire SCS complex. Results demonstrate that accumulation of succinyl-CoA in the absence of SCS leads to hypersuccinylation within the murine cerebral cortex. Specifically, increased succinylation is associated with functionally significant reduced activity of respiratory chain complex I and widescale alterations in chromatin landscape and gene expression. Integrative analysis of the transcriptomic data also reveals perturbations in regulatory networks of neuronal transcription in the KO forebrain. Together, these findings provide evidence that protein succinylation plays a significant role in the pathogenesis of SCS deficiency.
Assuntos
Mitocôndrias , Succinato-CoA Ligases , Humanos , Animais , Camundongos , Mitocôndrias/metabolismo , Acil Coenzima A/metabolismo , Succinato-CoA Ligases/genética , Succinato-CoA Ligases/metabolismo , Camundongos KnockoutRESUMO
Biallelic pathogenic variants in subunits of succinyl-CoA synthetase (SCS), a tricarboxylic acid (TCA) cycle enzyme, are associated with mitochondrial encephalomyopathy in humans. SCS catalyzes the interconversion of succinyl-CoA to succinate, coupled to substrate-level phosphorylation of either ADP or GDP, within the TCA cycle. SCS-deficient encephalomyopathy typically presents in infancy and early childhood, with many patients succumbing to the disease during childhood. Common symptoms include abnormal brain MRI, basal ganglia lesions and cerebral atrophy, severe hypotonia, dystonia, progressive psychomotor regression, and growth deficits. Although subunits of SCS were first identified as causal genes for progressive metabolic encephalomyopathy in the early 2000s, recent investigations are now beginning to unravel the pathomechanisms underlying this metabolic disorder. This article reviews the current understanding of SCS function within and outside the TCA cycle as it relates to the complex and multifactorial mechanisms underlying SCS-related mitochondrial encephalomyopathy.
Assuntos
Encefalomiopatias Mitocondriais , Succinato-CoA Ligases , Pré-Escolar , Humanos , Encefalomiopatias Mitocondriais/genética , Encefalomiopatias Mitocondriais/metabolismo , Mitocôndrias/metabolismo , Succinato-CoA Ligases/genética , Succinato-CoA Ligases/metabolismo , Estresse OxidativoRESUMO
Metabolic reprogramming plays a pivotal role in the differentiation and function of immune cells including dendritic cells (DCs). Regulatory DCs can be generated in regional tissue niches like splenic stroma and act as an important part of stromal control of immune response for the maintenance of immune tolerance. However, the metabolic alterations during splenic stroma-driven regulatory DCs differentiation and the metabolic enzyme involved in regulatory DCs function remain poorly understood. By combining metabolomic, transcriptomic, and functional investigations of mature DCs (maDCs) and diffDCs (regulatory DCs differentiated from activated mature DCs through coculturing with splenic stroma), here we identified succinate-CoA ligase subunit beta Suclg2 as a key metabolic enzyme that reprograms the proinflammatory status of mature DCs into a tolerogenic phenotype via preventing NF-κB signaling activation. diffDCs downregulate succinic acid levels and increase the Suclg2 expression along with their differentiation from mature DCs. Suclg2-interference impaired the tolerogenic function of diffDCs in inducing T cell apoptosis and enhanced activation of NF-κB signaling and expression of inflammatory genes CD40, Ccl5, and Il12b in diffDCs. Furthermore, we identified Lactb as a new positive regulator of NF-κB signaling in diffDCs whose succinylation at the lysine 288 residue was inhibited by Suclg2. Our study reveals that the metabolic enzyme Suclg2 is required to maintain the immunoregulatory function of diffDCs, adding mechanistic insights into the metabolic regulation of DC-based immunity and tolerance.
Assuntos
Células Dendríticas , NF-kappa B , Diferenciação Celular , Células Dendríticas/imunologia , Regulação da Expressão Gênica , Tolerância Imunológica , NF-kappa B/metabolismo , Transdução de Sinais , Succinato-CoA Ligases/imunologia , beta-Lactamases/imunologiaRESUMO
Although recent studies demonstrate active mitochondrial metabolism in cancers, the precise mechanisms through which mitochondrial factors contribute to cancer metastasis remain elusive. Through a customized mitochondrion RNAi screen, we identified succinyl-CoA ligase ADP-forming subunit beta (SUCLA2) as a critical anoikis resistance and metastasis driver in human cancers. Mechanistically, SUCLA2, but not the alpha subunit of its enzyme complex, relocates from mitochondria to the cytosol upon cell detachment where SUCLA2 then binds to and promotes the formation of stress granules. SUCLA2-mediated stress granules facilitate the protein translation of antioxidant enzymes including catalase, which mitigates oxidative stress and renders cancer cells resistant to anoikis. We provide clinical evidence that SUCLA2 expression correlates with catalase levels as well as metastatic potential in lung and breast cancer patients. These findings not only implicate SUCLA2 as an anticancer target, but also provide insight into a unique, noncanonical function of SUCLA2 that cancer cells co-opt to metastasize.
Assuntos
Neoplasias , Succinato-CoA Ligases , Humanos , Catalase/metabolismo , Grânulos de Estresse , Succinato-CoA Ligases/metabolismo , OxirreduçãoRESUMO
Succinyl-CoA synthetase (SCS) catalyzes a three-step reaction in the citric acid cycle with succinyl-phosphate proposed as a catalytic intermediate. However, there are no structural data to show the binding of succinyl-phosphate to SCS. Recently, the catalytic mechanism underlying acetyl-CoA production by ATP-citrate lyase (ACLY) has been debated. The enzyme belongs to the family of acyl-CoA synthetases (nucleoside diphosphate-forming) for which SCS is the prototype. It was postulated that the amino-terminal portion catalyzes the full reaction and the carboxy-terminal portion plays only an allosteric role. This interpretation was based on the partial loss of the catalytic activity of ACLY when Glu599 was mutated to Gln or Ala, and on the interpretation that the phospho-citryl-CoA intermediate was trapped in the 2.85â Å resolution structure from cryogenic electron microscopy (cryo-EM). To better resolve the structure of the intermediate bound to the E599Q mutant, the equivalent mutation, E105αQ, was made in human GTP-specific SCS. The structure of the E105αQ mutant shows succinyl-phosphate bound to the enzyme at 1.58â Å resolution when the mutant, after phosphorylation in solution by Mg2+-ATP, was crystallized in the presence of magnesium ions, succinate and desulfo-CoA. The E105αQ mutant is still active but has a specific activity that is 120-fold less than that of the wild-type enzyme, with apparent Michaelis constants for succinate and CoA that are 50-fold and 11-fold higher, respectively. Based on this high-resolution structure, the cryo-EM maps of the E599Q ACLY complex reported previously should have revealed the binding of citryl-phosphate and CoA and not phospho-citryl-CoA.
Assuntos
ATP Citrato (pro-S)-Liase , Succinato-CoA Ligases , ATP Citrato (pro-S)-Liase/química , ATP Citrato (pro-S)-Liase/genética , ATP Citrato (pro-S)-Liase/metabolismo , Acetilcoenzima A , Acil Coenzima A , Trifosfato de Adenosina/metabolismo , Cristalografia por Raios X , Difosfatos , Guanosina Trifosfato/metabolismo , Humanos , Magnésio , Complexos Multienzimáticos , Nucleosídeos , Oxo-Ácido-Liases , Succinato-CoA Ligases/química , Succinatos , Ácido Succínico/metabolismoRESUMO
The interconversion of guanosine triphosphate (GTP) and guanosine diphosphate (GDP) is known to be integral to a wide variety of biological cellular activities, yet to date there are no analytical methods available to directly detect the ratio of intracellular GTP to GDP. Herein, we report GRISerHR, a genetically encoded fluorescent biosensor to monitor the GTP : GDP ratio in multiple cell types and in various organelles under metabolic perturbation. Additionally, we characterized the differential mitochondrial GTP : GDP ratios resulting from genetic modulation of two isoforms of a tricarboxylic acid (TCA) cycle enzyme (succinyl-CoA synthetase; SCS-ATP and SCS-GTP) and of a phosphoenolpyruvate (PEP) cycle enzyme (PEPCK-M). Thus, our GRISerHR sensor achieves spatiotemporally precise detection of dynamic changes in the endogenous GTP : GDP ratio in living cells and can help deepen our understanding about the energy metabolic contributions of guanosine nucleotides in biology.
Assuntos
Técnicas Biossensoriais , Succinato-CoA Ligases , Guanosina Difosfato/metabolismo , Guanosina Trifosfato/metabolismo , Mitocôndrias/metabolismo , Succinato-CoA Ligases/metabolismoRESUMO
BACKGROUND: Succinate-CoA ligase/synthetase (SCS) deficiency is responsible for encephalomyopathy with mitochondrial DNA depletion and mild methylmalonic aciduria. Variants in SUCLG1, the nuclear gene encoding the alpha subunit of the SCS enzyme playing a pivotal role in maintaining mtDNA integrity and stability, are associated with mitochondrial DNA depletion syndrome 9 (MTDPS9). METHODS: In this study, we reported an infant with clinical features of MTDPS9 from China. Whole exome sequencing (WES) was used to identify the genetic cause. Bioinformatic analysis and mtDNA level detection were performed to assess pathogenicity. RESULTS: The proband manifested with hypotonia, lactic acidosis, mild methylmalonic aciduria, hearing loss and psychomotor retardation. WES identified new compound heterozygous SUCLG1 variants of c.601A>G (p.R201G) in exon 6 and c.871G>C (p.A291P) in exon 8. Computational analysis predicted that these missense variants might alter structure stability and mitochondrial translocation of SUCLG1. qRT-PCR showed 68% depletion of mtDNA content in proband as compared to controls. CONCLUSION: Novel compound heterozygous variants c.601A>G (p.R201G) and c.871G>C (p.A291P) in SUCLG1 may cause MTDPS9 in this family. Our finding should be helpful for molecular diagnosis, genetic counseling and clinical management of SCS deficiency disorders.
Assuntos
Erros Inatos do Metabolismo dos Aminoácidos , Succinato-CoA Ligases , Erros Inatos do Metabolismo dos Aminoácidos/genética , DNA Mitocondrial/genética , Humanos , Lactente , Mitocôndrias/genética , Succinato-CoA Ligases/química , Succinato-CoA Ligases/genéticaRESUMO
Glutaminase regulates glutaminolysis to promote cancer cell proliferation. However, the mechanism underlying glutaminase activity regulation is largely unknown. Here, we demonstrate that kidney-type glutaminase (GLS) is highly expressed in human pancreatic ductal adenocarcinoma (PDAC) specimens with correspondingly upregulated glutamine dependence for PDAC cell proliferation. Upon oxidative stress, the succinyl-coenzyme A (CoA) synthetase ADP-forming subunit ß (SUCLA2) phosphorylated by p38 mitogen-activated protein kinase (MAPK) at S79 dissociates from GLS, resulting in enhanced GLS K311 succinylation, oligomerization, and activity. Activated GLS increases glutaminolysis and the production of nicotinamide adenine dinucleotide phosphate (NADPH) and glutathione, thereby counteracting oxidative stress and promoting tumor cell survival and tumor growth in mice. In addition, the levels of SUCLA2 pS79 and GLS K311 succinylation, which were mutually correlated, were positively associated with advanced stages of PDAC and poor prognosis for patients. Our findings reveal critical regulation of GLS by SUCLA2-coupled GLS succinylation regulation and underscore the regulatory role of metabolites in glutaminolysis and PDAC development.
Assuntos
Carcinoma Ductal Pancreático/genética , Glutaminase/genética , Neoplasias Pancreáticas/genética , Succinato-CoA Ligases/genética , Animais , Carcinoma Ductal Pancreático/diagnóstico , Carcinoma Ductal Pancreático/enzimologia , Carcinoma Ductal Pancreático/mortalidade , Linhagem Celular Tumoral , Proliferação de Células , Regulação Neoplásica da Expressão Gênica , Glutaminase/metabolismo , Glutamina/metabolismo , Glutationa/metabolismo , Xenoenxertos , Humanos , Masculino , Camundongos , Camundongos Nus , NADP/metabolismo , Estresse Oxidativo , Neoplasias Pancreáticas/diagnóstico , Neoplasias Pancreáticas/enzimologia , Neoplasias Pancreáticas/mortalidade , Fosforilação , Prognóstico , Processamento de Proteína Pós-Traducional , Transdução de Sinais , Succinato-CoA Ligases/metabolismo , Ácido Succínico/metabolismo , Análise de Sobrevida , Proteínas Quinases p38 Ativadas por Mitógeno/genética , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismoRESUMO
Many bacteria and other organisms carry out fermentations forming acetate. These fermentations have broad importance for foods, agriculture, and industry. They also are important for bacteria themselves because they often generate ATP. Here, we found a biochemical pathway for forming acetate and synthesizing ATP that was unknown in fermentative bacteria. We found that the bacterium Cutibacterium granulosum formed acetate during fermentation of glucose. It did not use phosphotransacetylase or acetate kinase, enzymes found in nearly all acetate-forming bacteria. Instead, it used a pathway involving two different enzymes. The first enzyme, succinyl coenzyme A (succinyl-CoA):acetate CoA-transferase (SCACT), forms acetate from acetyl-CoA. The second enzyme, succinyl-CoA synthetase (SCS), synthesizes ATP. We identified the genes encoding these enzymes, and they were homologs of SCACT and SCS genes found in other bacteria. The pathway resembles one described in eukaryotes, but it uses bacterial, not eukaryotic, gene homologs. To find other instances of the pathway, we analyzed sequences of all biochemically characterized homologs of SCACT and SCS (103 enzymes from 64 publications). Homologs with similar enzymatic activity had similar sequences, enabling a large-scale search for them in genomes. We searched nearly 600 genomes of bacteria known to form acetate, and we found that 6% encoded homologs with SCACT and SCS activity. This included >30 species belonging to 5 different phyla, showing that a diverse range of bacteria encode the SCACT/SCS pathway. This work suggests the SCACT/SCS pathway is important for acetate formation in many branches of the tree of life. IMPORTANCE Pathways for forming acetate during fermentation have been studied for over 80 years. In that time, several pathways in a range of organisms, from bacteria to animals, have been described. However, one pathway (involving succinyl-CoA:acetate CoA-transferase and succinyl-CoA synthetase) has not been reported in prokaryotes. Here, we discovered enzymes for this pathway in the fermentative bacterium Cutibacterium granulosum. We also found >30 other fermentative bacteria that encode this pathway, demonstrating that it could be common. This pathway represents a new way for bacteria to form acetate from acetyl-CoA and synthesize ATP via substrate-level phosphorylation. It could be a target for controlling yield of acetate during fermentation, with relevance for foods, agriculture, and industry.
Assuntos
Acetatos/metabolismo , Trifosfato de Adenosina/metabolismo , Propionibacteriaceae/metabolismo , Succinato-CoA Ligases/metabolismo , Acetilcoenzima A/metabolismo , Coenzima A-Transferases/genética , Coenzima A-Transferases/metabolismo , Fermentação , Genoma Bacteriano , Propionibacteriaceae/genética , Succinato-CoA Ligases/genéticaRESUMO
Succinyl-CoA synthetase (SCS) catalyzes a reversible reaction that is the only substrate-level phosphorylation in the citric acid cycle. One of the essential steps for the transfer of the phosphoryl group involves the movement of the phosphohistidine loop between active site I, where CoA, succinate and phosphate bind, and active site II, where the nucleotide binds. Here, the first crystal structure of SCS revealing the conformation of the phosphohistidine loop in site II of the porcine GTP-specific enzyme is presented. The phosphoryl transfer bridges a distance of 29â Å between the binding sites for phosphohistidine in site I and site II, so these crystal structures support the proposed mechanism of catalysis by SCS. In addition, a second succinate-binding site was discovered at the interface between the α- and ß-subunits of SCS, and another magnesium ion was found that interacts with the side chains of Glu141ß and Glu204ß via water-mediated interactions. These glutamate residues interact with the active-site histidine residue when it is bound in site II.
Assuntos
Histidina/análogos & derivados , Succinato-CoA Ligases/química , Animais , Sítios de Ligação , Biocatálise , Cristalização , Cristalografia por Raios X , Ácido Glutâmico/química , Guanosina Difosfato/química , Guanosina Trifosfato/química , Histidina/química , Magnésio/química , Modelos Moleculares , Conformação Proteica , Ácido Succínico/química , SuínosRESUMO
Substrate specificity of an enzyme is an important characteristic of its mechanism of action. Investigation of the nucleotide specificity of Plasmodium falciparum succinyl-CoA synthetase (SCS; PfSCS) would provide crucial insights of its substrate recognition. Charged gatekeeper residues have been shown to alter the substrate specificity via electrostatic interactions with approaching substrates. The enzyme kinetics of recombinant PfSCS (wild-type), generated by refolding of the individual P. falciparum SCSß and Blastocystis SCSα subunits, demonstrated ADP-forming activity (KmATP = 48 µm). Further, the introduction of charged gatekeeper residues, either positive (Lys and Lys) or negative (Glu and Asp), resulted in significant reductions in the ATP affinity of PfSCS. It is interesting to note that the recombinant PfSCSß subunit can be refolded to a functional enzyme conformation using Blastocystis SCSα, indicating the possibility of subunits swapping among different organisms. These results concluded that electrostatic interactions at the gatekeeper region alone are insufficient to alter the substrate specificity of PfSCS, and further structural analysis with a particular focus on binding site architecture is required.
Assuntos
Mutação , Plasmodium falciparum/enzimologia , Succinato-CoA Ligases/química , Succinato-CoA Ligases/metabolismo , Trifosfato de Adenosina/metabolismo , Sítios de Ligação , Blastocystis/enzimologia , Nucleotídeos/metabolismo , Plasmodium falciparum/química , Ligação Proteica , Domínios Proteicos , Dobramento de Proteína , Eletricidade Estática , Especificidade por Substrato , Succinato-CoA Ligases/genéticaRESUMO
Growth of Geobacter sulfurreducens PCA on lactate was enhanced by laboratory adaptive evolution. The enhanced growth was considered to be attributed to increased expression of the sucCD genes, encoding a succinyl-coenzyme A (CoA) synthetase. To further investigate the function of the succinyl-CoA synthetase, the sucCD genes were deleted from G. sulfurreducens The mutant showed defective growth on lactate but not on acetate. Introduction of the sucCD genes into the mutant restored the full potential to grow on lactate. These results verify the importance of the succinyl-CoA synthetase in growth on lactate. Genome analysis of Geobacter species identified candidate genes, GSU1623, GSU1624, and GSU1620, for lactate dehydrogenase. Deletion mutants of the identified genes for d-lactate dehydrogenase (ΔGSU1623 ΔGSU1624 mutant) or l-lactate dehydrogenase (ΔGSU1620 mutant) could not grow on d-lactate or l-lactate but could grow on acetate and l- or d-lactate, respectively. Introduction of the respective genes into the mutants allowed growth on the corresponding lactate stereoisomer. These results suggest that the identified genes were essential for d- or l-lactate utilization. The lacZ reporter assay demonstrated that the putative promoter regions were more active during growth on lactate than during growth on acetate, indicating that the genes for the lactate dehydrogenases were expressed more during growth on lactate than during growth on acetate. The gene deletion phenotypes and the expression profiles indicate that there are metabolic switches between lactate and acetate. This study advances the understanding of anaerobic lactate utilization in G. sulfurreducensIMPORTANCE Lactate is a microbial fermentation product as well as a source of carbon and electrons for microorganisms in the environment. Furthermore, lactate is a common amendment for stimulation of microbial growth in environmental biotechnology applications. However, anaerobic metabolism of lactate has been poorly studied for environmentally relevant microorganisms. Geobacter species are found in various environments and environmental biotechnology applications. By employing genomic and genetic approaches, succinyl-CoA synthetase and lactate dehydrogenase were identified as key enzymes in anaerobic metabolism of lactate in Geobacter sulfurreducens, a representative Geobacter species. Differential gene expression during growth on lactate and acetate was observed, demonstrating that G. sulfurreducens could metabolically switch to adapt to available substrates in the environment. The findings provide new insights into basic physiology in lactate metabolism as well as cellular responses to growth conditions in the environment and can be informative for the application of lactate in environmental biotechnology.
Assuntos
Proteínas de Bactérias/metabolismo , Geobacter/enzimologia , L-Lactato Desidrogenase/metabolismo , Ácido Láctico/metabolismo , Succinato-CoA Ligases/metabolismo , Anaerobiose , Proteínas de Bactérias/genética , Regulação Bacteriana da Expressão Gênica , Geobacter/genética , Geobacter/metabolismo , L-Lactato Desidrogenase/genética , Succinato-CoA Ligases/genéticaRESUMO
SUCLA2 is a component of mitochondrial succinate-CoA ligase and nucleotide diphosphokinase activities. Its absence results in Krebs cycle failure, mitochondrial DNA depletion, and a childhood-fatal encephalomyopathy. We describe a purely neurologic allelic form of the disease consisting of deafness, putamenal hyperintensity on MRI and a myoclonic-dystonic movement disorder unchanging from childhood into, so far, the late fourth decade. We show that succinate supplementation circumvents the Krebs cycle block, but does not correct the neurologic disease. Our patients' Arg407Trp mutation has been reported in children with (yet) no MRI abnormalities. It remains possible that early succinate supplementation could impact the disease.
Assuntos
Surdez/genética , Transtornos dos Movimentos/genética , Succinato-CoA Ligases/genética , Surdez/tratamento farmacológico , Feminino , Humanos , Masculino , Transtornos dos Movimentos/tratamento farmacológico , Mutação de Sentido Incorreto , Linhagem , Ácido Succínico/uso terapêuticoRESUMO
Autoimmune T cells in rheumatoid arthritis (RA) have a defect in mitochondrial oxygen consumption and ATP production. Here, we identified suppression of the GDP-forming ß subunit of succinate-CoA ligase (SUCLG2) as an underlying abnormality. SUCLG2-deficient T cells reverted the tricarboxylic acid (TCA) cycle from the oxidative to the reductive direction, accumulated α-ketoglutarate, citrate, and acetyl-CoA (AcCoA), and differentiated into pro-inflammatory effector cells. In AcCoAhi RA T cells, tubulin acetylation stabilized the microtubule cytoskeleton and positioned mitochondria in a perinuclear location, resulting in cellular polarization, uropod formation, T cell migration, and tissue invasion. In the tissue, SUCLG2-deficient T cells functioned as cytokine-producing effector cells and were hyperinflammatory, a defect correctable by replenishing the enzyme. Preventing T cell tubulin acetylation by tubulin acetyltransferase knockdown was sufficient to inhibit synovitis. These data link mitochondrial failure and AcCoA oversupply to autoimmune tissue inflammation.
Assuntos
Artrite Reumatoide/imunologia , Succinato-CoA Ligases/imunologia , Linfócitos T/imunologia , Acetilcoenzima A/imunologia , Adulto , Idoso , Animais , Citocinas/imunologia , Feminino , Humanos , Masculino , Camundongos , Microtúbulos/imunologia , Pessoa de Meia-Idade , Linfócitos T/citologiaRESUMO
The mitochondrial encephalomyopathies represent a clinically heterogeneous group of neurodegenerative disorders. The clinical phenotype of patients could be explained by mutations of mitochondria-related genes, notably SUCLG1 and SUCLA2. Here, we presented a 5-year-old boy with clinical features of mitochondrial encephalomyopathy from Iran. Also, a systematic review was performed to explore the involvement of SUCLG1 mutations in published mitochondrial encephalomyopathies cases. Genotyping was performed by implementing whole-exome sequencing. Moreover, quantification of the mtDNA content was performed by real-time qPCR. We identified a novel, homozygote missense variant chr2: 84676796 A > T (hg19) in the SUCLG1 gene. This mutation substitutes Cys with Ser at the 60-position of the SUCLG1 protein. Furthermore, the in-silico analysis revealed that the mutated position in the genome is well conserved in mammalians, that implies mutation in this residue would possibly result in phenotypic consequences. Here, we identified a novel, homozygote missense variant chr2: 84676796 A > T in the SUCLG1 gene. Using a range of experimental and in silico analysis, we found that the mutation might explain the observed phenotype in the family.
Assuntos
DNA Mitocondrial/genética , Mitocôndrias/genética , Encefalomiopatias Mitocondriais/genética , Succinato-CoA Ligases/genética , Pré-Escolar , Homozigoto , Humanos , Irã (Geográfico) , Masculino , Mutação de Sentido IncorretoRESUMO
Mitochondrial acyl-coenzyme A species are emerging as important sources of protein modification and damage. Succinyl-CoA ligase (SCL) deficiency causes a mitochondrial encephalomyopathy of unknown pathomechanism. Here, we show that succinyl-CoA accumulates in cells derived from patients with recessive mutations in the tricarboxylic acid cycle (TCA) gene succinyl-CoA ligase subunit-ß (SUCLA2), causing global protein hyper-succinylation. Using mass spectrometry, we quantify nearly 1,000 protein succinylation sites on 366 proteins from patient-derived fibroblasts and myotubes. Interestingly, hyper-succinylated proteins are distributed across cellular compartments, and many are known targets of the (NAD+)-dependent desuccinylase SIRT5. To test the contribution of hyper-succinylation to disease progression, we develop a zebrafish model of the SCL deficiency and find that SIRT5 gain-of-function reduces global protein succinylation and improves survival. Thus, increased succinyl-CoA levels contribute to the pathology of SCL deficiency through post-translational modifications.
Assuntos
Acil Coenzima A/metabolismo , Doenças Mitocondriais/patologia , Succinato-CoA Ligases/genética , Animais , Células Cultivadas , Feminino , Humanos , Lactente , Lisina/metabolismo , Masculino , Camundongos , Camundongos Knockout , Mitocôndrias/metabolismo , Doenças Mitocondriais/genética , Doenças Mitocondriais/metabolismo , Mutação , Proteômica , Sirtuínas/deficiência , Sirtuínas/genética , Sirtuínas/metabolismo , Succinato-CoA Ligases/deficiência , Succinato-CoA Ligases/metabolismo , Análise de Sobrevida , Peixe-ZebraRESUMO
Neuroendocrine (NE) differentiation is a well-recognized phenotypic change of prostate cancer after androgen deprivation therapy (ADT), and it ultimately develops into an aggressive subset of this disease. However, the contribution of signaling pathways that lead to metabolic disorders and NE differentiation of prostate cancer remains unclear. In this study, we identified that ADT induced upregulation of the succinate-CoA ligase GDP-forming beta subunit (SUCLG2), which regulates succinate metabolism and NE differentiation of prostate cancer. We demonstrated a connection that upregulation of epidermal growth factor receptor (EGFR)-leukemia inhibitory factor receptor (LIFR) signaling induced SUCLG2 expression in prostate cancer cells. The LIFR is upregulated by nuclear EGFR, which acts as a transcriptional regulator, directly binds to the LIFR promoter, and drives NE differentiation and glycolysis of prostate cancer. LIFR upregulation is associated with SUCLG2, which increased succinate synthesis and enzymatic activities of mitochondrial nucleoside diphosphate kinase (NDPK) in prostate cancer cells. Knockdown of SUCLG2 suppressed NE differentiation in cultured cells and reduced prostate tumor growth in a xenograft model. Analysis of prostate tissue samples showed increased intensity of nuclear EGFR associated with the LIFR and SUCLG2 in castration-resistant prostate cancer tumors. Our study provides a mechanism whereby ADT upregulates EGFR-LIFR signaling that activates SUCLG2, which subsequently stimulates the metabolic changes associated with NE differentiation and aggressive prostate cancer phenotype.
Assuntos
Antagonistas de Androgênios/farmacologia , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Subunidade alfa de Receptor de Fator Inibidor de Leucemia/genética , Tumores Neuroendócrinos/genética , Neoplasias de Próstata Resistentes à Castração/genética , Succinato-CoA Ligases/metabolismo , Antagonistas de Androgênios/uso terapêutico , Animais , Diferenciação Celular/efeitos dos fármacos , Diferenciação Celular/genética , Linhagem Celular Tumoral , Núcleo Celular/patologia , Transdiferenciação Celular/efeitos dos fármacos , Transdiferenciação Celular/genética , Receptores ErbB/metabolismo , Técnicas de Silenciamento de Genes , Glicólise/efeitos dos fármacos , Glicólise/genética , Humanos , Subunidade alfa de Receptor de Fator Inibidor de Leucemia/metabolismo , Masculino , Camundongos , Tumores Neuroendócrinos/tratamento farmacológico , Tumores Neuroendócrinos/patologia , Regiões Promotoras Genéticas , Próstata/efeitos dos fármacos , Próstata/patologia , Neoplasias de Próstata Resistentes à Castração/tratamento farmacológico , Neoplasias de Próstata Resistentes à Castração/patologia , Receptores Androgênicos/metabolismo , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Succinato-CoA Ligases/genética , Regulação para Cima/efeitos dos fármacos , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Acetate:succinate CoA transferase (ASCT) is a mitochondrial enzyme that catalyzes the production of acetate and succinyl-CoA, which is coupled to ATP production with succinyl-CoA synthetase (SCS) in a process called the ASCT/SCS cycle. This cycle has been studied in Trypanosoma brucei (T. brucei), a pathogen of African sleeping sickness, and is involved in (i) ATP and (ii) acetate production and proceeds independent of oxygen and an electrochemical gradient. Interestingly, knockout of ASCT in procyclic form (PCF) of T. brucei cause oligomycin A-hypersensitivity phenotype indicating that ASCT/SCS cycle complements the deficiency of ATP synthase activity. In bloodstream form (BSF) of T. brucei, ATP synthase works in reverse to maintain the electrochemical gradient by hydrolyzing ATP. However, no information has been available on the source of ATP, although ASCT/SCS cycle could be a potential candidate. Regarding mitochondrial acetate production, which is essential for fatty acid biosynthesis and growth of T. brucei, ASCT or acetyl-CoA hydrolase (ACH) are known to be its source. Despite the importance of this cycle, direct evidence of its function is lacking, and there are no comprehensive biochemical or structural biology studies reported so far. Here, we show that in vitro-reconstituted ASCT/SCS cycle is highly specific towards acetyl-CoA and has a higher kcat than that of yeast and bacterial ATP synthases. Our results provide the first biochemical basis for (i) rescue of ATP synthase-deficient phenotype by ASCT/SCS cycle in PCF and (ii) a potential source of ATP for the reverse reaction of ATP synthase in BSF.