Cloning and characterisation of ZmZLP1, a gene encoding an endoplasmic reticulum-localised zinc transporter in Zea mays

2010 ◽  
Vol 37 (3) ◽  
pp. 194 ◽  
Author(s):  
Yao-Guang Xu ◽  
Bao-Sheng Wang ◽  
Jing-Juan Yu ◽  
Guang-Ming Ao ◽  
Qian Zhao
Keyword(s):  
Endoplasmic Reticulum ◽  
Zea Mays ◽  
Metal Ion ◽  
Yeast Cells ◽  
Growth Defect ◽  
Gene Encoding ◽  
Yeast Saccharomyces Cerevisiae ◽  
Maize Pollen ◽  
Unfolded Protein ◽  
The Unfolded Protein Response

The ZmZLP1 (ZmZIP-like protein) gene was isolated from a cDNA library of Zea mays L. (maize) pollen. Bioinformatics analysis indicated that ZmZLP1 shares many characteristics of the ZIP (ZRT/IRT-like protein) family of metal ion transporters. Under general nutrient conditions, the expression of ZmZLP1 was detected in both mature pollen and, less strongly, in male inflorescences, whereas an induction of the ZmZLP1 transcript was observed in roots after 12 h of zinc deprivation. The visualisation of GFP showed that ZmZLP1 was targeted to the endoplasmic reticulum (ER). To investigate the gene’s functions, we fused ZmZLP1 with the signal peptide of the plasma membrane-localised protein AtIRT1 and transformed this fusion protein into the zinc uptake-deficient yeast (Saccharomyces cerevisiae) strain ZHY3 and the wild-type strain DEY1457. The IRT1-ZmZLP1 transformants grew poorly on zinc-limited medium, and this growth defect was rescued by zinc supplementation, suggesting that ZmZLP1 is responsible for transporting zinc from the ER to the cytoplasm. Further research indicated that ZmZLP1 is involved in the unfolded protein response (UPR) pathway and enhances the heat resistance of yeast cells.

scholarly journals The unfolded protein response coordinates the production of endoplasmic reticulum protein and endoplasmic reticulum membrane.

1997 ◽  
Vol 8 (9) ◽  
pp. 1805-1814 ◽  
Author(s):  
J S Cox ◽  
R E Chapman ◽  
P Walter
Keyword(s):  
Endoplasmic Reticulum ◽  
Unfolded Protein Response ◽  
Secretory Pathway ◽  
Lipid Synthesis ◽  
Secretory Proteins ◽  
Endoplasmic Reticulum Membrane ◽  
Yeast Saccharomyces Cerevisiae ◽  
Unfolded Protein ◽  
The Unfolded Protein Response ◽  
Protein Response

The endoplasmic reticulum (ER) is a multifunctional organelle responsible for production of both lumenal and membrane components of secretory pathway compartments. Secretory proteins are folded, processed, and sorted in the ER lumen and lipid synthesis occurs on the ER membrane itself. In the yeast Saccharomyces cerevisiae, synthesis of ER components is highly regulated: the ER-resident proteins by the unfolded protein response and membrane lipid synthesis by the inositol response. We demonstrate that these two responses are intimately linked, forming different branches of the same pathway. Furthermore, we present evidence indicating that this coordinate regulation plays a role in ER biogenesis.

scholarly journals Zinc and the Msc2 zinc transporter protein are required for endoplasmic reticulum function

2004 ◽  
Vol 166 (3) ◽  
pp. 325-335 ◽  
Author(s):  
Charissa D. Ellis ◽  
Fudi Wang ◽  
Colin W. MacDiarmid ◽  
Suzanne Clark ◽  
Thomas Lyons ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Zinc Deficiency ◽  
Metal Ion ◽  
Zinc Homeostasis ◽  
Cation Diffusion ◽  
Transporter Protein ◽  
Unfolded Protein ◽  
Er Stress Response ◽  
The Unfolded Protein Response ◽  
Protein Response

In this report, we show that zinc is required for endoplasmic reticulum function in Saccharomyces cerevisiae. Zinc deficiency in this yeast induces the unfolded protein response (UPR), a system normally activated by unfolded ER proteins. Msc2, a member of the cation diffusion facilitator (CDF) family of metal ion transporters, was previously implicated in zinc homeostasis. Our results indicate that Msc2 is one route of zinc entry into the ER. Msc2 localizes to the ER when expressed at normal levels. UPR induction in low zinc is exacerbated in an msc2 mutant. Genetic and biochemical evidence indicates that this UPR induction is due to genuine ER dysfunction. Notably, we found that ER-associated protein degradation is defective in zinc-limited msc2 mutants. We also show that the vacuolar CDF proteins Zrc1 and Cot1 are other pathways of ER zinc acquisition. Finally, zinc deficiency up-regulates the mammalian ER stress response indicating a conserved requirement for zinc in ER function among eukaryotes.

scholarly journals Membrane expansion alleviates endoplasmic reticulum stress independently of the unfolded protein response

2009 ◽  
Vol 187 (4) ◽  
pp. 525-536 ◽  
Author(s):  
Sebastian Schuck ◽  
William A. Prinz ◽  
Kurt S. Thorn ◽  
Christiane Voss ◽  
Peter Walter
Keyword(s):  
Endoplasmic Reticulum ◽  
Er Stress ◽  
Unfolded Protein Response ◽  
Size Control ◽  
Yeast Saccharomyces Cerevisiae ◽  
Unfolded Protein ◽  
Er Chaperone ◽  
Key Factor ◽  
The Unfolded Protein Response ◽  
Protein Response

Cells constantly adjust the sizes and shapes of their organelles according to need. In this study, we examine endoplasmic reticulum (ER) membrane expansion during the unfolded protein response (UPR) in the yeast Saccharomyces cerevisiae. We find that membrane expansion occurs through the generation of ER sheets, requires UPR signaling, and is driven by lipid biosynthesis. Uncoupling ER size control and the UPR reveals that membrane expansion alleviates ER stress independently of an increase in ER chaperone levels. Converting the sheets of the expanded ER into tubules by reticulon overexpression does not affect the ability of cells to cope with ER stress, showing that ER size rather than shape is the key factor. Thus, increasing ER size through membrane synthesis is an integral yet distinct part of the cellular program to overcome ER stress.

scholarly journals Characterization of Constitutive macro-ER-phagy

2020 ◽  
Author(s):  
Zhanna Lipatova ◽  
Valeriya Gyurkovska ◽  
Sarah F. Zhao ◽  
Nava Segev
Keyword(s):  
Endoplasmic Reticulum ◽  
Membrane Proteins ◽  
Er Stress ◽  
Mammalian Cells ◽  
Normal Growth ◽  
Integral Membrane Proteins ◽  
Yeast Cells ◽  
Unfolded Protein ◽  
The Unfolded Protein Response ◽  
Protein Response

AbstractThirty percent of all cellular proteins are inserted into the endoplasmic reticulum (ER), which spans throughout the cytoplasm. Two well-established stress-induced pathways ensure quality control (QC) at the ER: ER-phagy and ER-associated degradation (ERAD), which shuttle cargo for degradation to the lysosome and proteasome, respectively. In contrast, not much is known about constitutive ER-phagy. We have previously reported that excess of integral-membrane proteins is delivered from the ER to the lysosome via autophagy during normal growth of yeast cells. Here, we characterize this pathway as constitutive ER-phagy. Constitutive and stress-induced ER-phagy share the basic macro-autophagy machinery including the conserved Atgs and Ypt1 GTPase. However, induction of stress-induced autophagy is not needed for constitutive ER-phagy to occur. Moreover, the selective receptors needed for starvation-induced ER-phagy, Atg39 and Atg40, are not required for constitutive ER-phagy and neither these receptors nor their cargos are delivered through it to the vacuole. As for ERAD, while constitutive ER-phagy recognizes cargo different from that recognized by ERAD, these two ER-QC pathways can partially substitute for each other. Because accumulation of membrane proteins is associated with disease, and constitutive ER-phagy players are conserved from yeast to mammalian cells, this process could be critical for human health.Author SummaryAccumulation of excess proteins can lead to their aggregation, which in turn can cause multiple disorders, notably neurodegenerative disease. Nutritional and endoplasmic-reticulum (ER) stress stimulate autophagy and ER-associated degradation (ERAD) to clear excess and misfolded proteins, respectively. However, not much is known about clearance of excess proteins during normal growth. We have previously shown that excess integral-membrane proteins are cleared from the ER by macro-autophagy during normal growth of yeast cells. Here we characterize this pathway as constitutive ER-phagy. While this pathway shares machinery of core Atgs and autophagosomes with nutritional stress-induced ER-phagy, it differs from the latter: It is independent of the stress response and of receptors needed for stress-induced ER-phagy, and while stress-induced ER-phagy is not discriminatory, constitutive ER-phagy has specific cargos. However, when constitutive ER-phagy fails, machinery specific to stress-induced ER-phagy can process its cargo. Moreover, constitutive ER-phagy is also not dependent on ER-stress or the unfolded protein response (UPR) stimulated by this stress, although its failure elicits UPR. Finally, constitutive ER-phagy and ERAD can partially process each other’s cargo upon failure. In summary, constitutive ER-phagy, which clears excess integral-membrane proteins from the ER during normal growth does not require nutritional or ER stress for its function.

scholarly journals Membrane aberrancy and unfolded proteins activate the endoplasmic reticulum stress sensor Ire1 in different ways

2011 ◽  
Vol 22 (18) ◽  
pp. 3520-3532 ◽  
Author(s):  
Thanyarat Promlek ◽  
Yuki Ishiwata-Kimata ◽  
Masahiro Shido ◽  
Mitsuru Sakuramoto ◽  
Kenji Kohno ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Transmembrane Domain ◽  
Membrane Lipid ◽  
Yeast Cells ◽  
Wild Type ◽  
Unfolded Proteins ◽  
Unfolded Protein ◽  
The Unfolded Protein Response ◽  
Protein Response

Eukaryotic cells activate the unfolded-protein response (UPR) upon endoplasmic reticulum (ER) stress, where the stress is assumed to be the accumulation of unfolded proteins in the ER. Consistent with previous in vitro studies of the ER-luminal domain of the mutant UPR initiator Ire1, our study show its association with a model unfolded protein in yeast cells. An Ire1 luminal domain mutation that compromises Ire1's unfolded-protein–associating ability weakens its ability to respond to stress stimuli, likely resulting in the accumulation of unfolded proteins in the ER. In contrast, this mutant was activated like wild-type Ire1 by depletion of the membrane lipid component inositol or by deletion of genes involved in lipid homeostasis. Another Ire1 mutant lacking the authentic luminal domain was up-regulated by inositol depletion as strongly as wild-type Ire1. We therefore conclude that the cytosolic (or transmembrane) domain of Ire1 senses membrane aberrancy, while, as proposed previously, unfolded proteins accumulating in the ER interact with and activate Ire1.

scholarly journals The Effects of Bergamot Polyphenolic Fraction, Cynara cardunculus, and Olea europea L. Extract on Doxorubicin-Induced Cardiotoxicity

Nutrients ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 2158
Author(s):  
Jessica Maiuolo ◽  
Irene Bava ◽  
Cristina Carresi ◽  
Micaela Gliozzi ◽  
Vincenzo Musolino ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Apoptotic Cell ◽  
Natural Compounds ◽  
Cynara Cardunculus ◽  
Unfolded Protein ◽  
Wide Range ◽  
Vitro Model ◽  
The Unfolded Protein Response ◽  
Protein Response

Doxorubicin is an anthracycline that is commonly used as a chemotherapy drug due to its cytotoxic effects. The clinical use of doxorubicin is limited due to its known cardiotoxic effects. Treatment with anthracyclines causes heart failure in 15–17% of patients, resulting in mitochondrial dysfunction, the accumulation of reactive oxygen species, intracellular calcium dysregulation, the deterioration of the cardiomyocyte structure, and apoptotic cell death. Polyphenols have a wide range of beneficial properties, and particular importance is given to Bergamot Polyphenolic Fraction; Oleuropein, one of the main polyphenolic compounds of olive oil; and Cynara cardunculus extract. These natural compounds have particular beneficial characteristics, owing to their high polyphenol contents. Among these, their antioxidant and antoproliferative properties are the most important. The aim of this paper was to investigate the effects of these three plant derivatives using an in vitro model of cardiotoxicity induced by the treatment of rat embryonic cardiomyoblasts (H9c2) with doxorubicin. The biological mechanisms involved and the crosstalk existing between the mitochondria and the endoplasmic reticulum were examined. Bergamot Polyphenolic Fraction, Oleuropein, and Cynara cardunculus extract were able to decrease the damage induced by exposure to doxorubicin. In particular, these natural compounds were found to reduce cell mortality and oxidative damage, increase the lipid content, and decrease the concentration of calcium ions that escaped from the endoplasmic reticulum. In addition, the direct involvement of this cellular organelle was demonstrated by silencing the ATF6 arm of the Unfolded Protein Response, which was activated after treatment with doxorubicin.

scholarly journals Pulsed Electric Field (PEF) Enhances Iron Uptake by the Yeast Saccharomyces cerevisiae

Biomolecules ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 850
Author(s):  
Karolina Nowosad ◽  
Monika Sujka ◽  
Urszula Pankiewicz ◽  
Damijan Miklavčič ◽  
Marta Arczewska
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Electric Field ◽  
Metal Ion ◽  
Treatment Time ◽  
Control Sample ◽  
Pulsed Electric Field ◽  
Yeast Cells ◽  
Iron Ions ◽  
Metal Ion Binding ◽  
Yeast Saccharomyces Cerevisiae

The aim of the study was to investigate the influence of a pulsed electric field (PEF) on the level of iron ion accumulation in Saccharomyces cerevisiae cells and to select PEF conditions optimal for the highest uptake of this element. Iron ions were accumulated most efficiently when their source was iron (III) nitrate. When the following conditions of PEF treatment were used: voltage 1500 V, pulse width 10 μs, treatment time 20 min, and a number of pulses 1200, accumulation of iron ions in the cells from a 20 h-culture reached a maximum value of 48.01 mg/g dry mass. Application of the optimal PEF conditions thus increased iron accumulation in cells by 157% as compared to the sample enriched with iron without PEF. The second derivative of the FTIR spectra of iron-loaded and -unloaded yeast cells allowed us to determine the functional groups which may be involved in metal ion binding. The exposure of cells to PEF treatment only slightly influenced the biomass and cell viability. However, iron-enriched yeast (both with or without PEF) showed lower fermentative activity than a control sample. Thus obtained yeast biomass containing a high amount of incorporated iron may serve as an alternative to pharmacological supplementation in the state of iron deficiency.

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