Metallomics最新文献

Zinc (Zn) is an essential nutrient supporting a range of critical processes. In the yeast Saccharomyces cerevisiae, Zn deficiency induces a transcriptional response mediated by the Zap1 activator, which controls a regulon of ∼80 genes. A subset support Zn homeostasis by promoting Zn uptake and its distribution between compartments, while the remainder mediate an 'adaptive response' to enhance fitness of Zn-deficient (ZnD) cells. The peroxiredoxin Tsa1 is a Zap1-regulated adaptive factor essential for the growth of ZnD yeast. Tsa1 can function as an antioxidant peroxidase, protein chaperone, or redox sensor: The latter activity oxidizes associated proteins via a redox relay mechanism. We previously reported that in ZnD cells, Tsa1 inhibits pyruvate kinase (Pyk1) to conserve phosphoenolpyruvate for aromatic amino acid synthesis. However, this regulation makes a relatively minor contribution to fitness in low Zn, suggesting that Tsa1 targets other pathways important to adaptation. Consistent with this model, the redox sensor function of Tsa1 was essential for growth of ZnD cells. Using a maltose binding protein-tagged version of Tsa1, we identified a redox-sensitive non-covalent interaction with Pyk1, and applied this system to identify multiple novel interacting partners. This interactome implicates Tsa1 in the regulation of critical processes including many Zn-dependent metabolic pathways. Interestingly, Zap1 is a Tsa1 target, as Tsa1 strongly promoted the oxidation of Zap1 activation domain 2 and was required for full Zap1 activity. Our findings reveal a novel posttranslational response to Zn deficiency, overlain on and interconnected with the Zap1-mediated transcriptional response.

The Suf pathway is the most common pathway for bacterial iron-sulfur cluster assembly and uses the SufBC2D complex as a scaffold for cluster formation. In most Gram-negative bacteria, the SufB subunit of SufBC2D accepts a persulfide from the transpersulfurase, SufE, for incorporation into nascent clusters. There is no reported structure for the SufBC2D-E complex and mechanistic details concerning the coordination of persulfide delivery with other SufBC2D activities are unclear. Using the Suf pathway from Escherichia coli as a model system, we report that SufE acts as a noncompetitive inhibitor of SufBC2D ATPase activity with a Ki value of 1.8 ± 0.2 µM. This value corresponds with a KD value of 1.6 ± 0.2 µM for SufE binding to the SufBC2D complex determined by fluorescence polarization. The rate of persulfide transfer from SufE to SufBC2D is impaired in the presence of ATP, suggesting that the two reactions are mutually exclusive. An AlphaFold3 model of the SufBC2D-E complex predicts electrostatic interactions between acidic residues on SufC and basic residues on the N-terminal helix of SufE. SufE variants at the K9 and R16 positions interfere with the ability of SufE to transfer persulfide to SufBC2D and to inhibit SufBC2D ATPase activity. In vivo complementation growth assays show that these SufE variants exhibit a slow-growth phenotype under iron starvation conditions, confirming the connection between SufE and SufC as important for optimal function in the Suf pathway. The mutual exclusivity of persulfide delivery from SufE and SufBC2D ATPase activity suggests an ordered mechanism for cluster assembly.

Cancer is an intractable global public health problem. The p53 protein encoded by the TP53 is a tumor suppressor, but it is mutated in many tumors, which promotes the initiation and progression of tumors. The mechanisms of p53 regulates tumors are focused on regulating apoptosis, cell cycle arrest, nutrient metabolism, iron metabolism, and redox levels. Copper is a necessary trace element, and abnormal copper homeostasis not only damages the organism but also affects tumor progression. It has confirmed that p53 can bind to copper, respond to copper levels, and regulate copper metabolism. Some anti-tumor mechanisms of copper-related compounds are related to p53. Herein, we focus on reviewing how to regulate copper-binding proteins by p53, as well as its involvement in copper-mediated cell death and tumor drug resistance. It summarizes the pertinent mechanisms of wild-type p53 in regulating cancers via copper metabolism, which aiming to provide new ideas for future cancer therapy.

Corynebacteria are commercially and medically important Gram-positive bacteria that can switch from aerobic to anaerobic respiration in response to low O2 and the availability of nitrate as an alternative electron acceptor. The narKGHJI operon encoding the respiratory nitrate reductase is under the control of a novel regulator, ArnR, which plays a major role in the aerobic/anaerobic respiratory switch. ArnR was previously shown to be an iron-sulfur cluster protein that modulates its DNA binding according to availability of O2. However, previous data suggest that it does not do this directly in response to O2, but instead by sensing nitric oxide (NO), which builds up only under low O2 through the activity of nitrate reductase. Here, we report spectroscopic and mass spectrometric studies of C. glutamicum ArnR and its reactions with O2 and NO. We demonstrate that ArnR is a dimer that binds a [4Fe-4S] cluster in each subunit, and this form of the protein binds tightly to DNA. The [4Fe-4S] cluster of AnrR degrades only very slowly in the presence of O2, consistent with the ability of ArnR to repress nar transcription under aerobic conditions. Reaction with NO results in the formation of mono- and di-nitrosylated forms of the [4Fe-4S] ArnR dimer, which exhibit altered DNA-binding characteristics such that the di-nitrosyl form no longer binds to promoter DNA (i.e. cluster degradation is not required in order to modulate DNA binding). These data are consistent with previous literature and lead us to propose a model for AnrR regulatory function.

The extensive contamination of terrestrial ecosystems with multiple potentially toxic elements (PTEs) necessitates elucidation of plant adaptive mechanisms under combined PTEs stress. This study examines the physiological adaptations, antioxidant regulation, and PTEs allocation patterns in Cunninghamia lanceolata seedlings exposed to lead (Pb) stress (Pb4, 4.0 mg kg-1 Pb; Pb40, 40 mg kg-1 Pb), cadmium (Cd) stress (Cd2, 2 mg kg-1 Cd; Cd20, 20 mg kg-1 Cd), and combined Pb and Cd stress. Results demonstrated concentration-dependent inhibition of biomass production and chlorophyll b biosynthesis under both single and combined PTEs stress conditions. Different responses in superoxide dismutase activity were observed under combined stress compared to the controls, with lower concentration Pb stress causing notably higher enzymatic activation compared to higher concentration Pb stress. Elevated Cd concentrations resulted in significant accumulation of malondialdehyde in leaf tissues, indicating membrane damage. Lead preferentially accumulated in leaves under single Pb stress, while Cd predominantly accumulated in root systems. However, when the plants were exposed to combined Pb and Cd stress, the PTEs translocation pathways in the plants were altered, which resulted in a greater retention of Cd in the stems compared to when the plants were exposed to the single PTE stress. These findings provide insights into species-specific PTE homeostasis mechanisms under polymetallic stress, thereby providing theoretical foundations for the development of phytoremediation strategies in environments contaminated with multiple PTEs.

Ferroptosis, a recently discovered iron-dependent regulated form of cell death, is characterised by lipid peroxidation and oxidative stress. Recent studies suggested that ferroptosis plays a pivotal role in the pathogenesis of chronic obstructive pulmonary disease (COPD), a progressive and irreversible lung disorder, marked by airflow limitation, emphysema, and chronic bronchitis. Cigarette smoke (CS), one of the prominent risk factors for COPD, is known to induce ferroptosis by generating reactive oxygen species (ROS), depleting antioxidant defences, such as glutathione and glutathione peroxidase 4, and disrupting iron homeostasis. These molecular disturbances lead to cell damage, alveolar destruction, and vascular dysfunction, contributing to disease progression and exacerbations. Ferroptosis is also linked with key COPD mechanisms, which are responsible for mitochondrial dysfunction, inflammation, pulmonary hypertension, and CS-induced irregular distribution of iron-binding proteins. A promising therapeutic strategy for mitigating COPD pathogenesis is targeting ferroptosis via iron chelators, lipid peroxide inhibitors, and antioxidant upregulation. Understanding the regulatory mechanisms governing ferroptosis in lung tissue damage could help identify novel biomarkers and effective treatment strategies. This review explores the mechanistic role of ferroptosis in COPD and uncovers the potential intervention methods that may improve clinical outcomes.

Characterization of serum metal element concentrations in pregnancy enables the elucidation of relationships with maternal-fetal and neonatal health. Metal elements in the blood serve as essential cofactors for enzymatic reactions and contribute to blood gas homeostasis, hormone synthesis, and physiological immune function for mother and fetus. Sub-optimal concentrations of some metals have been linked to adverse outcomes, including preterm birth, low birth weight, and impaired neurodevelopment. Maternal obesity also adversely influences metabolic status, including metal metabolism, with the potential for a heightened risk of complications at delivery and long-term health issues in offspring. Research on metal element levels in pregnant women with obesity and their effects on pregnancy outcomes is however limited. This study aims to characterize mid-gestation serum concentrations of 18 metal elements in samples from 755 pregnant women with obesity enrolled in the UK Pregnancies Better Eating and Activity Trial (UPBEAT) and identify associations with pregnancy outcomes. We found that calcium concentration tended to decrease with increasing parity, with an estimated reduction of 6.03 mg/L in multiparous participants compared to nulliparous participants (95% CI: -9.50 to -2.57 mg/L, P = 0.001). Additionally, elevated manganese concentrations at mid-pregnancy were associated with an increased incidence of antepartum haemorrhage after 34 weeks (OR: 4.62, 95% CI: 2.06-12.4, P < 0.001), and higher maternal phosphorus levels were linked to neonatal intensive care unit admissions (OR: 2.83, 95% CI: 1.75-4.67, P < 0.001). A future focus on dysregulation of these metal elements is needed to improve understanding of the clinical associations observed.

Zinc is central to the function of many proteins, yet the mechanisms of zinc homeostasis and their interplay with other cellular systems remain underexplored. In this study, we employ data-dependent acquisition (DDA) and data-independent acquisition (DIA) mass spectrometry to investigate proteome changes in Pseudomonas aeruginosa under conditions of different zinc availability. Using both methods, we detected a combined 2143 unique proteins, 1578 of which were identified by both DDA and DIA. We demonstrated that most of the previously described Zn homeostasis systems exhibit proteomic responses that follow similar trends to those seen in transcriptomics studies. Furthermore, changes in abundance of multiple Zn-metalloproteins and Zn-independent homologs were clearly observable, with respective increases and decreases when Zn was provided, though the magnitude of these changes varied. Most of the Zn-metalloproteins observed were located in one of two Zur-regulated operons between PA5534 and PA5541. This study provides a view of Zn homeostasis mechanisms that is complementary to existing transcriptomics investigations: as gene transcripts are not strictly proportional to the actual distribution of proteins within a cell, analysis of the proteome offers another way to assess the relative use and importance of similar or ostensibly redundant systems in different conditions and can highlight shifts in metal prioritization between metalloproteins.

Zinc(II) ions play manifold roles in human health; dysregulation of zinc homeostasis has been implicated in a number of diseases and pathological conditions. Because zinc(II) is spectroscopically silent, it cannot be detected directly by conventional fluorescence microscopy. As a result, investigators seeking to image zinc(II) in biological systems frequently turn to small-molecule fluorescent sensors that selectively respond to the presence of the ion. This tutorial review describes methods for delivering such small-molecule probes to discrete subcellular locales. Attention is given to the preparation of conjugates in which well-characterized sensors are tethered to molecular homing moieties that accumulate in particular organelles or other compartments. Hybrid approaches that entail enzyme-mediated localization of synthetic constructs, as well as other novel techniques, are also discussed. The various fluorescent probe targeting methods described here enable opportunities for new discoveries in zinc biology.

Metals in circulation and urine had been implicated in atherosclerosis progression, but spatial distribution of metals within plaques and their association with plaque stability remained unclear. This study aimed to clarify differences of metal deposition between symptomatic and asymptomatic carotid plaques and metal spatial distribution within atherosclerotic plaques. We enrolled 15 asymptomatic and 53 symptomatic atherosclerotic plaque specimens during carotid endarterectomy. Each plaque was divided into the plaque core and thickened intimal area. We analyzed the difference of metals within plaques between symptomatic and asymptomatic groups and correlations between age and metal deposition. Besides, 12 additional symptomatic atherosclerotic plaques were used to map metal element distribution by laser ablation inductively coupled plasma mass spectrometry to analyze relative abundance of metal across pathological characteristics of plaques. Significantly higher levels of vanadium, iron, copper, molybdenum, and cadmium were found in the core area of symptomatic plaques compared to asymptomatic plaques, while no difference was observed in plaque thickened intimal area. Copper and lead deposition in core region of symptomatic plaques significantly increased with age. Spatial mapping indicated distinct metal distribution patterns: copper was primarily localized in necrotic and calcified regions, iron was in intraplaque hemorrhage, and calcium and zinc were in calcified areas. Elevated metal accumulation and distinct spatial distribution of metal elements within atherosclerotic plaques might contribute to plaque instability. Our findings highlighted the potential role of metal elements in plaque progression and value of spatial localization methods in studying the pathological roles of metal elements.