A dynamic pathway for calcium-independent activation of CaMKII by methionine oxidation
TL;DR: It is shown that oxidation of paired regulatory domain methionine residues sustains CaMKII activity in the absence of Ca2+/CaM and highlights the critical importance of oxidation-dependent CaMK II activation to AngII and ischemic myocardial apoptosis.
About: This article is published in Cell.The article was published on 2008-05-02 and is currently open access. It has received 989 citations till now. The article focuses on the topics: Ca2+/calmodulin-dependent protein kinase & Angiotensin II.
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TL;DR: The sources of ROS within cells and what is known regarding how intracellular oxidant levels are regulated are discussed, with the recent observations that reduction–oxidation (redox)-dependent regulation has a crucial role in an ever-widening range of biological activities.
Abstract: Reactive oxygen species (ROS), which were originally characterized in terms of their harmful effects on cells and invading microorganisms, are increasingly implicated in various cell fate decisions and signal transduction pathways. The mechanism involved in ROS-dependent signalling involves the reversible oxidation and reduction of specific amino acids, with crucial reactive Cys residues being the most frequent target. In this Review, we discuss the sources of ROS within cells and what is known regarding how intracellular oxidant levels are regulated. We further discuss the recent observations that reduction-oxidation (redox)-dependent regulation has a crucial role in an ever-widening range of biological activities - from immune function to stem cell self-renewal, and from tumorigenesis to ageing.
1,515 citations
TL;DR: ROS chemistry and their pleiotropy make them difficult to localize, to quantify and to manipulate — challenges the authors must overcome to translate ROS biology into medical advances.
Abstract: Reactive oxygen species (ROS) react preferentially with certain atoms to modulate functions ranging from cell homeostasis to cell death. Molecular actions include both inhibition and activation of proteins, mutagenesis of DNA and activation of gene transcription. Cellular actions include promotion or suppression of inflammation, immunity and carcinogenesis. ROS help the host to compete against microorganisms and are also involved in intermicrobial competition. ROS chemistry and their pleiotropy make them difficult to localize, to quantify and to manipulate — challenges we must overcome to translate ROS biology into medical advances.
1,130 citations
TL;DR: Current knowledge about how these unique proteins perform their functions at the molecular level is discussed and new insights into the roles that selenoproteins play in human health are highlighted.
Abstract: Selenium is an essential micronutrient with important functions in human health and relevance to several pathophysiological conditions. The biological effects of selenium are largely mediated by se...
872 citations
TL;DR: It is shown that receptor-interacting protein 3 (RIP3) triggers myocardial necroptosis, in addition to apoptosis and inflammation, through activation of Ca2+-calmodulin–dependent protein kinase (CaMKII) rather than through the well-established RIP3 partners RIP1 and MLKL.
Abstract: Regulated necrosis (necroptosis) and apoptosis are crucially involved in severe cardiac pathological conditions, including myocardial infarction, ischemia-reperfusion injury and heart failure. Whereas apoptotic signaling is well defined, the mechanisms that underlie cardiomyocyte necroptosis remain elusive. Here we show that receptor-interacting protein 3 (RIP3) triggers myocardial necroptosis, in addition to apoptosis and inflammation, through activation of Ca(2+)-calmodulin-dependent protein kinase (CaMKII) rather than through the well-established RIP3 partners RIP1 and MLKL. In mice, RIP3 deficiency or CaMKII inhibition ameliorates myocardial necroptosis and heart failure induced by ischemia-reperfusion or by doxorubicin treatment. RIP3-induced activation of CaMKII, via phosphorylation or oxidation or both, triggers opening of the mitochondrial permeability transition pore and myocardial necroptosis. These findings identify CaMKII as a new RIP3 substrate and delineate a RIP3-CaMKII-mPTP myocardial necroptosis pathway, a promising target for the treatment of ischemia- and oxidative stress-induced myocardial damage and heart failure.
533 citations
TL;DR: O-GlcNAc modification of CaMKII is a novel signalling event in pathways that may contribute critically to cardiac and neuronal pathophysiology in diabetes and other diseases.
Abstract: Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) is an enzyme with important regulatory functions in the heart and brain, and its chronic activation can be pathological. CaMKII activation is seen in heart failure, and can directly induce pathological changes in ion channels, Ca(2+) handling and gene transcription. Here, in human, rat and mouse, we identify a novel mechanism linking CaMKII and hyperglycaemic signalling in diabetes mellitus, which is a key risk factor for heart and neurodegenerative diseases. Acute hyperglycaemia causes covalent modification of CaMKII by O-linked N-acetylglucosamine (O-GlcNAc). O-GlcNAc modification of CaMKII at Ser 279 activates CaMKII autonomously, creating molecular memory even after Ca(2+) concentration declines. O-GlcNAc-modified CaMKII is increased in the heart and brain of diabetic humans and rats. In cardiomyocytes, increased glucose concentration significantly enhances CaMKII-dependent activation of spontaneous sarcoplasmic reticulum Ca(2+) release events that can contribute to cardiac mechanical dysfunction and arrhythmias. These effects were prevented by pharmacological inhibition of O-GlcNAc signalling or genetic ablation of CaMKIIδ. In intact perfused hearts, arrhythmias were aggravated by increased glucose concentration through O-GlcNAc- and CaMKII-dependent pathways. In diabetic animals, acute blockade of O-GlcNAc inhibited arrhythmogenesis. Thus, O-GlcNAc modification of CaMKII is a novel signalling event in pathways that may contribute critically to cardiac and neuronal pathophysiology in diabetes and other diseases.
472 citations
References
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Harvard University1, University of Texas Health Science Center at Houston2, Stony Brook University3, University of Manitoba4, Washington University in St. Louis5, University of Arizona6, University of Missouri7, Université de Montréal8, Icahn School of Medicine at Mount Sinai9, Laval University10, Yeshiva University11
TL;DR: In patients with asymptomatic left ventricular dysfunction after myocardial infarction, long-term administration of captopril was associated with an improvement in survival and reduced morbidity and mortality due to major cardiovascular events.
Abstract: Background. Left ventricular dilatation and dysfunction after myocardial infarction are major predictors of death. In experimental and clinical studies, long-term therapy with the angiotensin-converting—enzyme inhibitor captopril attenuated ventricular dilatation and remodeling. We investigated whether captopril could reduce morbidity and mortality in patients with left ventricular dysfunction after a myocardial infarction. Methods. Within 3 to 16 days after myocardial infarction, 2231 patients with ejection fractions of 40 percent or less but without overt heart failure or symptoms of myocardial ischemia were randomly assigned to receive double-blind treatment with either placebo (1116 patients) or captopril (1115 patients) and were followed for an average of 42 months. Results. Mortality from all causes was significantly reduced in the captopril group (228 deaths, or 20 percent) as compared with the placebo group (275 deaths, or 25 percent); the reduction in risk was 19 percent (95 percent conf...
5,503 citations
"A dynamic pathway for calcium-indep..." refers background in this paper
..., 2007), while AngII antagonist drugs are a mainstay for reducing mortality in patients with structural heart disease (Pfeffer et al., 1992; Pfeffer et al., 2003)....
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...Angiotensin II (AngII) also increases ROS in heart (Doerries et al., 2007), while AngII antagonist drugs are a mainstay for reducing mortality in patients with structural heart disease (Pfeffer et al., 1992, 2003)....
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TL;DR: Dicer is a member of the RNase III family of nucleases that specifically cleave double-stranded RNAs, and is evolutionarily conserved in worms, flies, plants, fungi and mammals, and has a distinctive structure, which includes a helicase domain and dualRNase III motifs.
Abstract: RNA interference (RNAi) is the mechanism through which double-stranded RNAs silence cognate genes. In plants, this can occur at both the transcriptional and the post-transcriptional levels; however, in animals, only post-transcriptional RNAi has been reported to date. In both plants and animals, RNAi is characterized by the presence of RNAs of about 22 nucleotides in length that are homologous to the gene that is being suppressed. These 22-nucleotide sequences serve as guide sequences that instruct a multicomponent nuclease, RISC, to destroy specific messenger RNAs. Here we identify an enzyme, Dicer, which can produce putative guide RNAs. Dicer is a member of the RNase III family of nucleases that specifically cleave double-stranded RNAs, and is evolutionarily conserved in worms, flies, plants, fungi and mammals. The enzyme has a distinctive structure, which includes a helicase domain and dual RNase III motifs. Dicer also contains a region of homology to the RDE1/QDE2/ARGONAUTE family that has been genetically linked to RNAi.
5,229 citations
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...html) and others (Hammond et al., 2000; Bernstein et al., 2001; Brummelkamp et al., 2002)....
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TL;DR: It is shown that siRNA expression mediated by this vector causes efficient and specific down-regulation of gene expression, resulting in functional inactivation of the targeted genes.
Abstract: Mammalian genetic approaches to study gene function have been hampered by the lack of tools to generate stable loss-of-function phenotypes efficiently. We report here a new vector system, named pSUPER, which directs the synthesis of small interfering RNAs (siRNAs) in mammalian cells. We show that siRNA expression mediated by this vector causes efficient and specific down-regulation of gene expression, resulting in functional inactivation of the targeted genes. Stable expression of siRNAs using this vector mediates persistent suppression of gene expression, allowing the analysis of loss-of-function phenotypes that develop over longer periods of time. Therefore, the pSUPER vector constitutes a new and powerful system to analyze gene function in a variety of mammalian cell types.
4,937 citations
Additional excerpts
...html) and others (Hammond et al., 2000; Bernstein et al., 2001; Brummelkamp et al., 2002)....
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TL;DR: Metoprolol controlled release/extended release (CR/XL) once daily in addition to standard therapy improved survival and the drug was well tolerated.
4,707 citations