The response of fission yeast Schizosaccharomyces pombe to zinc deficiency

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Response of Schizosaccharomyces pombe to Zinc Deficiency▿ †

A component of the cellular response to zinc deficiency operates via control of transcript abundance. Therefore, microarray analysis was employed to identify Schizosaccharomyces pombe genes whose mRNA levels are regulated by intracellular zinc status. A set of 57 genes whose mRNA levels were substantially reduced in response to zinc deficiency was identified, while the mRNA levels of 63 genes were increased by this condition. In order to investigate the mechanisms that control these responses, a genetic screen was employed to identify mutants with defective zinc-responsive gene expression. Two strains (II-1 and V7) that were identified by this screen harbor mutations that are linked to zrt1+, which encodes a putative Zrt/IRT-like protein (ZIP) zinc uptake transporter. Importantly, zrt1+ mRNA levels are increased in response to zinc deprivation, and cells lacking functional Zrt1 are highly impaired in their ability to proliferate at limiting zinc concentrations. Furthermore, zrt1 null cells were found to have severely reduced zinc contents, indicating that Zrt1 functions as a key regulator of intracellular zinc levels in fission yeast. The deletion of fet4+, another zinc-responsive gene encoding a putative metal ion transporter, exacerbated the phenotypes associated with the loss of Zrt1, suggesting that Fet4 also plays a role in zinc uptake under limiting conditions

Endoplasmic reticulum stress causes insulin resistance by inhibiting delivery of newly synthesised insulin receptors to the cell surface

Accumulation of unfolded proteins in the endoplasmic reticulum (ER) causes ER stress and activates a signalling network known as the unfolded protein response (UPR). Here we characterise how ER stress and the UPR inhibit insulin signalling. We find that ER stress inhibits insulin signalling by depleting the cell surface population of the insulin receptor. ER stress inhibits proteolytic maturation of insulin proreceptors by interfering with transport of newly synthesised insulin proreceptors from the ER to the plasma membrane. Activation of AKT, a major target of the insulin signalling pathway, by a cytosolic, membrane-bound chimera between the AP20187-inducible FV2E dimerisation domain and the cytosolic protein tyrosine kinase domain of the insulin receptor was not affected by ER stress. Hence, signalling events in the UPR, such as activation of the JNK MAP kinases or the pseudokinase TRB3 by the ER stress sensors IRE1α and PERK, do not contribute to inhibition of signal transduction in the insulin signalling pathway. Indeed, pharmacologic inhibition and genetic ablation of JNKs, as well as silencing of expression of TRB3, did not restore insulin sensitivity or rescue processing of newly synthesised insulin receptors in ER-stressed cells

A chemical potentiator of copper-accumulation used to investigate the iron-regulons of Saccharomyces cerevisiae

The extreme resistance of Saccharomyces cerevisiae to copper is overcome by 2-(6-benzyl-2-pyridyl)quinazoline (BPQ), providing a chemical-biology tool which has been exploited in two lines of discovery. First, BPQ is shown to form a red (BPQ)2Cu(I) complex and promote Ctr1-independent copper-accumulation in whole cells and in mitochondria isolated from treated cells. Multiple phenotypes, including loss of aconitase activity, are consistent with copper-BPQ mediated damage to mitochondrial iron-sulphur clusters. Thus, a biochemical basis of copper-toxicity in S. cerevisiae is analogous to other organisms. Second, iron regulons controlled by Aft1/2, Cth2 and Yap5 that respond to mitochondrial iron-sulphur cluster status are modulated by copper-BPQ causing iron hyper-accumulation via up-regulated iron-import. Comparison of copper-BPQ treated, untreated and copper-only treated wild-type and fra2Δ by RNAseq has uncovered a new candidate Aft1 target-gene (LSO1) and paralogous non-target (LSO2), plus nine putative Cth2 target-transcripts. Two lines of evidence confirm that Fra2 dominates basal repression of the Aft1/2 regulons in iron-replete cultures. Fra2-independent control of these regulons is also observed but cth2 itself appears to be atypically Fra2-dependent. However, control of Cth2-target transcripts which is independent of cth2 transcript abundance or of Fra2, is also quantified. Use of copper-BPQ supports a substantial contribution of metabolite repression to iron-regulation

Structure and Metal Loading of a Soluble Periplasm Cuproprotein*

A copper-trafficking pathway was found to enable Cu2+ occupancy of a soluble periplasm protein, CucA, even when competing Zn2+ is abundant in the periplasm. Here, we solved the structure of CucA (a new cupin) and found that binding of Cu2+, but not Zn2+, quenches the fluorescence of Trp165, which is adjacent to the metal site. Using this fluorescence probe, we established that CucA becomes partly occupied by Zn2+ following exposure to equimolar Zn2+ and Cu2+. Cu2+-CucA is more thermodynamically stable than Zn2+-CucA but k(Zn→Cu)exchange is slow, raising questions about how the periplasm contains solely the Cu2+ form. We discovered that a copper-trafficking pathway involving two copper transporters (CtaA and PacS) and a metallochaperone (Atx1) is obligatory for Cu2+-CucA to accumulate in the periplasm. There was negligible CucA protein in the periplasm of ΔctaA cells, but the abundance of cucA transcripts was unaltered. Crucially, ΔctaA cells overaccumulate low Mr copper complexes in the periplasm, and purified apoCucA can readily acquire Cu2+ from ΔctaA periplasm extracts, but in vivo apoCucA fails to come into contact with these periplasmic copper pools. Instead, copper traffics via a cytoplasmic pathway that is coupled to CucA translocation to the periplasm

2021 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations : summary From the Basic Life Support; Advanced Life Support; Neonatal Life Support; Education, Implementation, and Teams; First Aid Task Forces; and the COVID-19 Working Group

The International Liaison Committee on Resuscitation initiated a continuous review of new, peer-reviewed published cardiopulmonary resuscitation science. This is the fifth annual summary of the International Liaison Committee on Resuscitation International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations; a more comprehensive review was done in 2020. This latest summary addresses the most recently published resuscitation evidence reviewed by International Liaison Committee on Resuscitation task force science experts. Topics covered by systematic reviews in this summary include resuscitation topics of video-based dispatch systems; head-up cardiopulmonary resuscitation; early coronary angiography after return of spontaneous circulation; cardiopulmonary resuscitation in the prone patient; cord management at birth for preterm and term infants; devices for administering positive-pressure ventilation at birth; family presence during neonatal resuscitation; self-directed, digitally based basic life support education and training in adults and children; coronavirus disease 2019 infection risk to rescuers from patients in cardiac arrest; and first aid topics, including cooling with water for thermal burns, oral rehydration for exertional dehydration, pediatric tourniquet use, and methods of tick removal. Members from 6 International Liaison Committee on Resuscitation task forces have assessed, discussed, and debated the quality of the evidence, according to the Grading of Recommendations Assessment, Development, and Evaluation criteria, and their statements include consensus treatment recommendations or good practice statements. Insights into the deliberations of the task forces are provided in Justification and Evidence-to-Decision Framework Highlights sections. In addition, the task forces listed priority knowledge gaps for further research

2022 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations: Summary From the Basic Life Support; Advanced Life Support; Pediatric Life Support; Neonatal Life Support; Education, Implementation, and Teams; and First Aid Task Forces

This is the sixth annual summary of the International Liaison Committee on Resuscitation International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations. This summary addresses the most recently published resuscitation evidence reviewed by International Liaison Committee on Resuscitation Task Force science experts. Topics covered by systematic reviews include cardiopulmonary resuscitation during transport; approach to resuscitation after drowning; passive ventilation; minimizing pauses during cardiopulmonary resuscitation; temperature management after cardiac arrest; use of diagnostic point-of-care ultrasound during cardiac arrest; use of vasopressin and corticosteroids during cardiac arrest; coronary angiography after cardiac arrest; public-access defibrillation devices for children; pediatric early warning systems; maintaining normal temperature immediately after birth; suctioning of amniotic fluid at birth; tactile stimulation for resuscitation immediately after birth; use of continuous positive airway pressure for respiratory distress at term birth; respiratory and heart rate monitoring in the delivery room; supraglottic airway use in neonates; prearrest prediction of in-hospital cardiac arrest mortality; basic life support training for likely rescuers of high-risk populations; effect of resuscitation team training; blended learning for life support training; training and recertification for resuscitation instructors; and recovery position for maintenance of breathing and prevention of cardiac arrest. Members from 6 task forces have assessed, discussed, and debated the quality of the evidence using Grading of Recommendations Assessment, Development, and Evaluation criteria and generated consensus treatment recommendations. Insights into the deliberations of the task forces are provided in the Justification and Evidence-to-Decision Framework Highlights sections, and priority knowledge gaps for future research are listed.</jats:p