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1.
Nat Commun ; 15(1): 5804, 2024 Jul 10.
Artículo en Inglés | MEDLINE | ID: mdl-38987268

RESUMEN

Environmental and physiological situations can challenge the balance between protein synthesis and folding capacity of the endoplasmic reticulum (ER) and cause ER stress, a potentially lethal condition. The unfolded protein response (UPR) restores ER homeostasis or actuates programmed cell death (PCD) when ER stress is unresolved. The cell fate determination mechanisms of the UPR are not well understood, especially in plants. Here, we integrate genetics and ER stress profiling with natural variation and quantitative trait locus analysis of 350 natural accessions of the model species Arabidopsis thaliana. Our analyses implicate a single nucleotide polymorphism to the loss of function of the general PCD regulator BON-ASSOCIATED PROTEIN2 (BAP2) in UPR outcomes. We establish that ER stress-induced BAP2 expression is antagonistically regulated by the UPR master regulator, inositol-requiring enzyme 1 (IRE1), and that BAP2 controls adaptive UPR amplitude in ER stress and ignites pro-death mechanisms in conditions of UPR insufficiency.


Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Estrés del Retículo Endoplásmico , Regulación de la Expresión Génica de las Plantas , Respuesta de Proteína Desplegada , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Respuesta de Proteína Desplegada/genética , Estrés del Retículo Endoplásmico/genética , Retículo Endoplásmico/metabolismo , Apoptosis/genética , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas Serina-Treonina Quinasas/genética , Sitios de Carácter Cuantitativo , Polimorfismo de Nucleótido Simple
3.
Methods Mol Biol ; 2772: 239-247, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38411818

RESUMEN

The unfolded protein response (UPR) is a highly regulated signaling pathway that is largely conserved across eukaryotes. It is essential for cell homeostasis under environmental and physiological conditions that perturb the protein folding in the endoplasmic reticulum (ER). Arabidopsis is one of the outstanding multicellular model systems in which to investigate the UPR. Here, we described a protocol to induce the UPR in plants, specifically Arabidopsis, and to estimate their ability to cope with ER stress through the quantification of physiological parameters.


Asunto(s)
Arabidopsis , Respuesta de Proteína Desplegada , Estrés del Retículo Endoplásmico , Retículo Endoplásmico , Eucariontes
4.
Plant Cell ; 34(11): 4428-4452, 2022 10 27.
Artículo en Inglés | MEDLINE | ID: mdl-35938694

RESUMEN

Ca2+ signaling is central to plant development and acclimation. While Ca2+-responsive proteins have been investigated intensely in plants, only a few Ca2+-permeable channels have been identified, and our understanding of how intracellular Ca2+ fluxes is facilitated remains limited. Arabidopsis thaliana homologs of the mammalian channel-forming mitochondrial calcium uniporter (MCU) protein showed Ca2+ transport activity in vitro. Yet, the evolutionary complexity of MCU proteins, as well as reports about alternative systems and unperturbed mitochondrial Ca2+ uptake in knockout lines of MCU genes, leave critical questions about the in vivo functions of the MCU protein family in plants unanswered. Here, we demonstrate that MCU proteins mediate mitochondrial Ca2+ transport in planta and that this mechanism is the major route for fast Ca2+ uptake. Guided by the subcellular localization, expression, and conservation of MCU proteins, we generated an mcu triple knockout line. Using Ca2+ imaging in living root tips and the stimulation of Ca2+ transients of different amplitudes, we demonstrated that mitochondrial Ca2+ uptake became limiting in the triple mutant. The drastic cell physiological phenotype of impaired subcellular Ca2+ transport coincided with deregulated jasmonic acid-related signaling and thigmomorphogenesis. Our findings establish MCUs as a major mitochondrial Ca2+ entry route in planta and link mitochondrial Ca2+ transport with phytohormone signaling.


Asunto(s)
Arabidopsis , Animales , Arabidopsis/genética , Arabidopsis/metabolismo , Calcio/metabolismo , Canales de Calcio/genética , Canales de Calcio/metabolismo , Mitocondrias/metabolismo , Proteínas Mitocondriales/metabolismo , Proteínas de Unión al Calcio/genética , Proteínas de Unión al Calcio/metabolismo , Mamíferos/metabolismo
6.
Plant Cell ; 34(4): 1375-1395, 2022 03 29.
Artículo en Inglés | MEDLINE | ID: mdl-35078237

RESUMEN

Redox processes are at the heart of universal life processes, such as metabolism, signaling, or folding of secreted proteins. Redox landscapes differ between cell compartments and are strictly controlled to tolerate changing conditions and to avoid cell dysfunction. While a sophisticated antioxidant network counteracts oxidative stress, our understanding of reductive stress responses remains fragmentary. Here, we observed root growth impairment in Arabidopsis thaliana mutants of mitochondrial alternative oxidase 1a (aox1a) in response to the model thiol reductant dithiothreitol (DTT). Mutants of mitochondrial uncoupling protein 1 (ucp1) displayed a similar phenotype indicating that impaired respiratory flexibility led to hypersensitivity. Endoplasmic reticulum (ER) stress was enhanced in the mitochondrial mutants and limiting ER oxidoreductin capacity in the aox1a background led to synergistic root growth impairment by DTT, indicating that mitochondrial respiration alleviates reductive ER stress. The observations that DTT triggered nicotinamide adenine dinucleotide (NAD) reduction in vivo and that the presence of thiols led to electron transport chain activity in isolated mitochondria offer a biochemical framework of mitochondrion-mediated alleviation of thiol-mediated reductive stress. Ablation of transcription factor Arabidopsis NAC domain-containing protein17 (ANAC017) impaired the induction of AOX1a expression by DTT and led to DTT hypersensitivity, revealing that reductive stress tolerance is achieved by adjusting mitochondrial respiratory capacity via retrograde signaling. Our data reveal an unexpected role for mitochondrial respiratory flexibility and retrograde signaling in reductive stress tolerance involving inter-organelle redox crosstalk.


Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Retículo Endoplásmico/metabolismo , Estrés del Retículo Endoplásmico/genética , Mitocondrias/metabolismo , Proteínas Mitocondriales/genética , Proteínas Mitocondriales/metabolismo , Transducción de Señal/fisiología , Compuestos de Sulfhidrilo/metabolismo , Factores de Transcripción/metabolismo
7.
Methods Mol Biol ; 2363: 153-163, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-34545492

RESUMEN

Transient transformation assays for the analysis of protein localization are routinely used as rapid and convenient alternatives to stable transformation. In this chapter, we describe two transient gene expression assays (e.g., isolation and transformation of protoplasts, and agroinfiltration of leaves) optimized for Arabidopsis thaliana, and we combine them with fluorescence microscopy, with the final aim to investigate in vivo the subcellular localization of a mitochondrial protein of interest fused to a fluorescent reporter.


Asunto(s)
Arabidopsis , Arabidopsis/genética , Proteínas de Arabidopsis , Proteínas Mitocondriales/genética , Hojas de la Planta , Plantas Modificadas Genéticamente/genética , Protoplastos
8.
Plant Physiol ; 187(4): 1985-2004, 2021 12 04.
Artículo en Inglés | MEDLINE | ID: mdl-33905517

RESUMEN

Recent insights about the transport mechanisms involved in the in and out of calcium ions in plant organelles, and their role in the regulation of cytosolic calcium homeostasis in different signaling pathways.


Asunto(s)
Adaptación Fisiológica/efectos de los fármacos , Transporte Biológico/efectos de los fármacos , Señalización del Calcio/efectos de los fármacos , Calcio/metabolismo , Orgánulos/metabolismo , Células Vegetales/metabolismo , Transducción de Señal/efectos de los fármacos , Citosol/metabolismo , Redes y Vías Metabólicas
9.
Plant J ; 101(2): 420-441, 2020 01.
Artículo en Inglés | MEDLINE | ID: mdl-31520498

RESUMEN

Mitochondria host vital cellular functions, including oxidative phosphorylation and co-factor biosynthesis, which are reflected in their proteome. At the cellular level plant mitochondria are organized into hundreds of discrete functional entities, which undergo dynamic fission and fusion. It is the individual organelle that operates in the living cell, yet biochemical and physiological assessments have exclusively focused on the characteristics of large populations of mitochondria. Here, we explore the protein composition of an individual average plant mitochondrion to deduce principles of functional and structural organisation. We perform proteomics on purified mitochondria from cultured heterotrophic Arabidopsis cells with intensity-based absolute quantification and scale the dataset to the single organelle based on criteria that are justified by experimental evidence and theoretical considerations. We estimate that a total of 1.4 million protein molecules make up a single Arabidopsis mitochondrion on average. Copy numbers of the individual proteins span five orders of magnitude, ranging from >40 000 for Voltage-Dependent Anion Channel 1 to sub-stoichiometric copy numbers, i.e. less than a single copy per single mitochondrion, for several pentatricopeptide repeat proteins that modify mitochondrial transcripts. For our analysis, we consider the physical and chemical constraints of the single organelle and discuss prominent features of mitochondrial architecture, protein biogenesis, oxidative phosphorylation, metabolism, antioxidant defence, genome maintenance, gene expression, and dynamics. While assessing the limitations of our considerations, we exemplify how our understanding of biochemical function and structural organization of plant mitochondria can be connected in order to obtain global and specific insights into how organelles work.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Mitocondrias/metabolismo , Orgánulos/metabolismo , Proteómica , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Bases de Datos de Proteínas , Mitocondrias/genética , Biogénesis de Organelos , Orgánulos/genética , Proteoma/metabolismo
10.
Proc Natl Acad Sci U S A ; 117(1): 741-751, 2020 01 07.
Artículo en Inglés | MEDLINE | ID: mdl-31871212

RESUMEN

Seeds preserve a far developed plant embryo in a quiescent state. Seed metabolism relies on stored resources and is reactivated to drive germination when the external conditions are favorable. Since the switchover from quiescence to reactivation provides a remarkable case of a cell physiological transition we investigated the earliest events in energy and redox metabolism of Arabidopsis seeds at imbibition. By developing fluorescent protein biosensing in intact seeds, we observed ATP accumulation and oxygen uptake within minutes, indicating rapid activation of mitochondrial respiration, which coincided with a sharp transition from an oxidizing to a more reducing thiol redox environment in the mitochondrial matrix. To identify individual operational protein thiol switches, we captured the fast release of metabolic quiescence in organello and devised quantitative iodoacetyl tandem mass tag (iodoTMT)-based thiol redox proteomics. The redox state across all Cys peptides was shifted toward reduction from 27.1% down to 13.0% oxidized thiol. A large number of Cys peptides (412) were redox switched, representing central pathways of mitochondrial energy metabolism, including the respiratory chain and each enzymatic step of the tricarboxylic acid (TCA) cycle. Active site Cys peptides of glutathione reductase 2, NADPH-thioredoxin reductase a/b, and thioredoxin-o1 showed the strongest responses. Germination of seeds lacking those redox proteins was associated with markedly enhanced respiration and deregulated TCA cycle dynamics suggesting decreased resource efficiency of energy metabolism. Germination in aged seeds was strongly impaired. We identify a global operation of thiol redox switches that is required for optimal usage of energy stores by the mitochondria to drive efficient germination.


Asunto(s)
Arabidopsis/fisiología , Ciclo del Ácido Cítrico/fisiología , Germinación/fisiología , Mitocondrias/metabolismo , Semillas/metabolismo , Adenosina Trifosfato/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Glutatión Reductasa/genética , Glutatión Reductasa/metabolismo , Oxidación-Reducción , Oxígeno/metabolismo , Plantas Modificadas Genéticamente , Proteómica/métodos , Semillas/citología , Semillas/crecimiento & desarrollo , Tiorredoxina h/genética , Tiorredoxina h/metabolismo , Reductasa de Tiorredoxina-Disulfuro/genética , Reductasa de Tiorredoxina-Disulfuro/metabolismo
11.
Plant Direct ; 3(11): e00187, 2019 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-31799493

RESUMEN

The unfolded protein response (UPR), a highly conserved set of eukaryotic intracellular signaling cascades, controls the homeostasis of the endoplasmic reticulum (ER) in normal physiological growth and situations causing accumulation of potentially toxic levels of misfolded proteins in the ER, a condition known as ER stress. During evolution, eukaryotic lineages have acquired multiple UPR effectors, which have increased the pliability of cytoprotective responses to physiological and environmental stresses. The ER-associated protein kinase and ribonuclease IRE1 is a UPR effector that is conserved from yeast to metazoans and plants. IRE1 assumes dispensable roles in growth in yeast but it is essential in mammals and plants. The Arabidopsis genome encodes two isoforms of IRE1, IRE1A and IRE1B, whose protein functional domains are conserved across eukaryotes. Here, we describe the identification of a third Arabidopsis IRE1 isoform, IRE1C. This protein lacks the ER lumenal domain that has been implicated in sensing ER stress in the IRE1 isoforms known to date. Through functional analyses, we demonstrate that IRE1C is not essential in growth and stress responses when deleted from the genome singularly or in combination with an IRE1A knockout allele. However, we found that IRE1C exerts an essential role in gametogenesis when IRE1B is also depleted. Our results identify a novel, plant-specific IRE1 isoform and highlight that at least the control of gametogenesis in Arabidopsis requires an unexpected functional coordination of IRE1C and IRE1B. More broadly, our findings support the existence of a functional form of IRE1 that is required for development despite the remarkable absence of a protein domain that is critical for the function of other known IRE1 isoforms.

12.
New Phytol ; 224(4): 1668-1684, 2019 12.
Artículo en Inglés | MEDLINE | ID: mdl-31386759

RESUMEN

Hypoxia regularly occurs during plant development and can be induced by the environment through, for example, flooding. To understand how plant tissue physiology responds to progressing oxygen restriction, we aimed to monitor subcellular physiology in real time and in vivo. We establish a fluorescent protein sensor-based system for multiparametric monitoring of dynamic changes in subcellular physiology of living Arabidopsis thaliana leaves and exemplify its applicability for hypoxia stress. By monitoring cytosolic dynamics of magnesium adenosine 5'-triphosphate, free calcium ion concentration, pH, NAD redox status, and glutathione redox status in parallel, linked to transcriptional and metabolic responses, we generate an integrated picture of the physiological response to progressing hypoxia. We show that the physiological changes are surprisingly robust, even when plant carbon status is modified, as achieved by sucrose feeding or extended night. Inhibition of the mitochondrial respiratory chain causes dynamics of cytosolic physiology that are remarkably similar to those under oxygen depletion, highlighting mitochondrial electron transport as a key determinant of the cellular consequences of hypoxia beyond the organelle. A broadly applicable system for parallel in vivo sensing of plant stress physiology is established to map out the physiological context under which both mitochondrial retrograde signalling and low oxygen signalling occur, indicating shared upstream stimuli.


Asunto(s)
Arabidopsis/metabolismo , Citosol/metabolismo , Mitocondrias/metabolismo , Células Vegetales/metabolismo , Adenosina Trifosfato/metabolismo , Arabidopsis/citología , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Calcio/metabolismo , Carbono/metabolismo , Transporte de Electrón , Glutatión/metabolismo , Concentración de Iones de Hidrógeno , Proteínas Luminiscentes/genética , Proteínas Luminiscentes/metabolismo , NAD/metabolismo , Oxígeno/metabolismo , Hojas de la Planta/citología , Hojas de la Planta/metabolismo , Plantas Modificadas Genéticamente
13.
New Phytol ; 221(3): 1649-1664, 2019 02.
Artículo en Inglés | MEDLINE | ID: mdl-30347449

RESUMEN

Hydrogen peroxide (H2 O2 ) is ubiquitous in cells and at the centre of developmental programmes and environmental responses. Its chemistry in cells makes H2 O2 notoriously hard to detect dynamically, specifically and at high resolution. Genetically encoded sensors overcome persistent shortcomings, but pH sensitivity, silencing of expression and a limited concept of sensor behaviour in vivo have hampered any meaningful H2 O2 sensing in living plants. We established H2 O2 monitoring in the cytosol and the mitochondria of Arabidopsis with the fusion protein roGFP2-Orp1 using confocal microscopy and multiwell fluorimetry. We confirmed sensor oxidation by H2 O2 , show insensitivity to physiological pH changes, and demonstrated that glutathione dominates sensor reduction in vivo. We showed the responsiveness of the sensor to exogenous H2 O2 , pharmacologically-induced H2 O2 release, and genetic interference with the antioxidant machinery in living Arabidopsis tissues. Monitoring intracellular H2 O2 dynamics in response to elicitor exposure reveals the late and prolonged impact of the oxidative burst in the cytosol that is modified in redox mutants. We provided a well defined toolkit for H2 O2 monitoring in planta and showed that intracellular H2 O2 measurements only carry meaning in the context of the endogenous thiol redox systems. This opens new possibilities to dissect plant H2 O2 dynamics and redox regulation, including intracellular NADPH oxidase-mediated ROS signalling.


Asunto(s)
Arabidopsis/metabolismo , Proteínas Fluorescentes Verdes/metabolismo , Peróxido de Hidrógeno/metabolismo , Espacio Intracelular/metabolismo , Estallido Respiratorio , Compuestos de Sulfhidrilo/metabolismo , Arabidopsis/efectos de los fármacos , Citosol/efectos de los fármacos , Citosol/metabolismo , Glutatión/metabolismo , Concentración de Iones de Hidrógeno , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Oxidación-Reducción , Estallido Respiratorio/efectos de los fármacos , Plantones/efectos de los fármacos , Plantones/metabolismo , Transducción de Señal/efectos de los fármacos , Vitamina K 3/farmacología
14.
Nat Commun ; 9(1): 3918, 2018 09 25.
Artículo en Inglés | MEDLINE | ID: mdl-30254194

RESUMEN

The unfolded protein response (UPR) of the endoplasmic reticulum constitutes a conserved and essential cytoprotective pathway designed to survive biotic and abiotic stresses that alter the proteostasis of the endoplasmic reticulum. The UPR is typically considered cell-autonomous and it is yet unclear whether it can also act systemically through non-cell autonomous signaling. We have addressed this question using a genetic approach coupled with micro-grafting and a suite of molecular reporters in the model plant species Arabidopsis thaliana. We show that the UPR has a non-cell autonomous component, and we demonstrate that this is partially mediated by the intercellular movement of the UPR transcription factor bZIP60 facilitating systemic UPR signaling. Therefore, in multicellular eukaryotes such as plants, non-cell autonomous UPR signaling relies on the systemic movement of at least a UPR transcriptional modulator.


Asunto(s)
Arabidopsis/genética , Retículo Endoplásmico/metabolismo , Transducción de Señal/fisiología , Respuesta de Proteína Desplegada/fisiología , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/genética , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/metabolismo , Retículo Endoplásmico/genética , Estrés del Retículo Endoplásmico/genética , Estrés del Retículo Endoplásmico/fisiología , Regulación de la Expresión Génica de las Plantas , Proteínas Fluorescentes Verdes/genética , Proteínas Fluorescentes Verdes/metabolismo , Microscopía Confocal , Chaperonas Moleculares/genética , Chaperonas Moleculares/metabolismo , Plantas Modificadas Genéticamente , Transducción de Señal/genética , Respuesta de Proteína Desplegada/genética
15.
Proc Natl Acad Sci U S A ; 115(22): E5203-E5212, 2018 05 29.
Artículo en Inglés | MEDLINE | ID: mdl-29760094

RESUMEN

The unfolded protein response (UPR) is an ancient signaling pathway designed to protect cells from the accumulation of unfolded and misfolded proteins in the endoplasmic reticulum (ER). Because misregulation of the UPR is potentially lethal, a stringent surveillance signaling system must be in place to modulate the UPR. The major signaling arms of the plant UPR have been discovered and rely on the transcriptional activity of the transcription factors bZIP60 and bZIP28 and on the kinase and ribonuclease activity of IRE1, which splices mRNA to activate bZIP60. Both bZIP28 and bZIP60 modulate UPR gene expression to overcome ER stress. In this study, we demonstrate at a genetic level that the transcriptional role of bZIP28 and bZIP60 in ER-stress responses is antagonized by nonexpressor of PR1 genes 1 (NPR1), a critical redox-regulated master regulator of salicylic acid (SA)-dependent responses to pathogens, independently of its role in SA defense. We also establish that the function of NPR1 in the UPR is concomitant with ER stress-induced reduction of the cytosol and translocation of NPR1 to the nucleus where it interacts with bZIP28 and bZIP60. Our results support a cellular role for NPR1 as well as a model for plant UPR regulation whereby SA-independent ER stress-induced redox activation of NPR1 suppresses the transcriptional role of bZIP28 and bZIP60 in the UPR.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Estrés del Retículo Endoplásmico/fisiología , Retículo Endoplásmico/metabolismo , Respuesta de Proteína Desplegada/fisiología , Arabidopsis/genética , Arabidopsis/metabolismo , Arabidopsis/fisiología , Proteínas de Arabidopsis/genética , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/genética , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/metabolismo , Retículo Endoplásmico/genética , Ácido Salicílico/metabolismo
16.
Plant J ; 93(1): 155-165, 2018 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-29124827

RESUMEN

The unfolded protein response (UPR) is an ancient signaling pathway that commits to life-or-death outcomes in response to proteotoxic stress in the endoplasmic reticulum (ER). In plants, the membrane-tethered transcription factor bZIP28 and the ribonuclease-kinase IRE1 along with its splicing target, bZIP60, govern the two cytoprotective UPR signaling pathways known to date. The conserved ER membrane-associated BAX inhibitor 1 (BI1) modulates ER stress-induced programmed cell death through yet-unknown mechanisms. Despite the significance of the UPR for cell homeostasis, in plants the regulatory circuitry underlying ER stress resolution is still largely unmapped. To gain insights into the coordination of plant UPR strategies, we analyzed the functional relationship of the UPR modulators through the analysis of single and higher order mutants of IRE1, bZIP60, bZIP28 and BI1 in experimental conditions causing either temporary or chronic ER stress. We established a functional duality of bZIP28 and bZIP60, as they exert partially independent tissue-specific roles in recovery from ER stress, but redundantly actuate survival strategies in chronic ER stress. We also discovered that BI1 attenuates the pro-survival function of bZIP28 in ER stress resolution and, differently to animal cells, it does not temper the ribonuclease activity of inositol-requiring enzyme 1 (IRE1) under temporary ER stress. Together these findings reveal a functional independence of bZIP28 and bZIP60 in plant UPR, and identify an antagonizing role of BI1 in the pro-adaptive signaling mediated by bZIP28, bringing to light the distinctive complexity of the unfolded protein response (UPR) in plants.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/metabolismo , Estrés del Retículo Endoplásmico , Transducción de Señal , Respuesta de Proteína Desplegada , Arabidopsis/fisiología , Proteínas de Arabidopsis/genética , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/genética , Retículo Endoplásmico/metabolismo , Regulación de la Expresión Génica de las Plantas , Empalme del ARN
17.
Methods Mol Biol ; 1691: 231-238, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29043682

RESUMEN

The unfolded protein response (UPR) is a highly regulated signaling pathway that is largely conserved across eukaryotes. It is essential for cell homeostasis under environmental and physiological conditions that perturb the protein folding in the endoplasmic reticulum (ER). Arabidopsis is one of the outstanding multicellular model systems in which to investigate the UPR. Here, we described a protocol to induce the UPR in plants, specifically arabidopsis, and to estimate their ability to cope with ER stress through the quantification of physiological parameters.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Retículo Endoplásmico/metabolismo , Respuesta de Proteína Desplegada , Arabidopsis/efectos de los fármacos , Retículo Endoplásmico/efectos de los fármacos , Estrés del Retículo Endoplásmico/efectos de los fármacos , Tunicamicina/farmacología , Respuesta de Proteína Desplegada/efectos de los fármacos
18.
Plant J ; 90(4): 671-682, 2017 May.
Artículo en Inglés | MEDLINE | ID: mdl-27943485

RESUMEN

Much like a factory, the endoplasmic reticulum (ER) assembles simple cellular building blocks into complex molecular machines known as proteins. In order to protect the delicate protein folding process and ensure the proper cellular delivery of protein products under environmental stresses, eukaryotes have evolved a set of signaling mechanisms known as the unfolded protein response (UPR) to increase the folding capacity of the ER. This process is particularly important in plants, because their sessile nature commands adaptation for survival rather than escape from stress. As such, plants make special use of the UPR, and evidence indicates that the master regulators and downstream effectors of the UPR have distinct roles in mediating cellular processes that affect organism growth and development as well as stress responses. In this review we outline recent developments in this field that support a strong relevance of the UPR to many areas of plant life.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Homeostasis/fisiología , Transducción de Señal/fisiología , Respuesta de Proteína Desplegada/fisiología , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Estrés del Retículo Endoplásmico/genética , Estrés del Retículo Endoplásmico/fisiología , Homeostasis/genética , Transducción de Señal/genética , Respuesta de Proteína Desplegada/genética
19.
Plant J ; 89(3): 486-501, 2017 02.
Artículo en Inglés | MEDLINE | ID: mdl-27747970

RESUMEN

Completion of a plant's life cycle depends on successful prioritization of signaling favoring either growth or defense. Although hormones are pivotal regulators of growth-defense tradeoffs, the underlying signaling mechanisms remain obscure. The unfolded protein response (UPR) is essential for physiological growth as well as management of endoplasmic reticulum (ER) stress in unfavorable growth conditions. The plant UPR transducers are the kinase and ribonuclease IRE1 and the transcription factors bZIP28 and bZIP60. We analyzed management of the tradeoff between growth and ER stress defense by the stress response hormone salicylic acid (SA) and the UPR, which is modulated by SA via unknown mechanisms. We show that the plant growth and stress regulator CPR5, which represses accumulation of SA, favors growth in physiological conditions through inhibition of the SA-dependent IRE1-bZIP60 arm that antagonizes organ growth; CPR5 also favors growth in stress conditions through repression of ER stress-induced bZIP28/IRE1-bZIP60 arms. By demonstrating a physical interaction of CPR5 with bZIP60 and bZIP28, we provide mechanistic insights into CPR5-mediated modulation of UPR signaling. These findings define a critical surveillance strategy for plant growth-ER stress defense tradeoffs based on CPR5 and SA-modulated UPR signaling, whereby CPR5 acts as a positive modulator of growth in physiological conditions and in stress by antagonizing SA-dependent growth inhibition through UPR modulation.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Estrés del Retículo Endoplásmico , Proteínas de la Membrana/metabolismo , Ácido Salicílico/metabolismo , Respuesta de Proteína Desplegada , Arabidopsis/genética , Arabidopsis/crecimiento & desarrollo , Proteínas de Arabidopsis/genética , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/genética , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/metabolismo , Regulación del Desarrollo de la Expresión Génica , Regulación de la Expresión Génica de las Plantas , Proteínas de la Membrana/genética , Mutación , Plantas Modificadas Genéticamente , Unión Proteica , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Plantones/genética , Plantones/crecimiento & desarrollo , Plantones/metabolismo , Transducción de Señal , Técnicas del Sistema de Dos Híbridos
20.
Curr Opin Plant Biol ; 27: 59-66, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-26149756

RESUMEN

To overcome endoplasmic reticulum (ER) stress, ER-localized stress sensors actuate distinct downstream organelle-nucleus signaling pathways to invoke a cytoprotective response, known as the unfolded protein response (UPR). Compared to yeast and metazoans, plant UPR studies are more recent but nevertheless fascinating. Here we discuss recent discoveries in plant UPR, highlight conserved and unique features of the plant UPR as well as critical yet-open questions whose answers will likely make significant contributions to the understanding plant ER stress management.


Asunto(s)
Estrés del Retículo Endoplásmico , Regulación de la Expresión Génica de las Plantas , Fenómenos Fisiológicos de las Plantas , Respuesta de Proteína Desplegada
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