Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Resultados 1 - 20 de 47
Filtrar
1.
Plant J ; 104(6): 1712-1723, 2020 12.
Artículo en Inglés | MEDLINE | ID: mdl-33080095

RESUMEN

Plants employ multiple mechanisms to cope with a constantly changing and challenging environment, including using the ubiquitin proteasome system (UPS) to alter their proteome to assist in initiating, modulating and terminating responses to stress. We previously reported that the ubiquitin ligase XBAT35.2 mediates the proteasome-dependent degradation of Accelerated Cell Death 11 (ACD11) to promote pathogen defense. Here, we demonstrate roles for XBAT35.2 and ACD11 in abiotic stress tolerance. As seen in response to pathogen infection, abiotic stress stabilizes XBAT35.2 and the abundance of ACD11 rose consistently with increasing concentrations of abscisic acid (ABA) and salt. Surprisingly, exposure to ABA and salt increased the stability of ACD11, and the overexpression of ACD11 improves plant survival of salt and drought stress, suggesting a role for ACD11 in promoting tolerance. Prolonged exposure to high concentrations of ABA or salt resulted in ubiquitination and the proteasome-dependent degradation of ACD11, however. The stress-induced turnover of ACD11 requires XBAT35.2, as degradation is slowed in the absence of the E3 ubiquitin ligase. Consistent with XBAT35.2 mediating the proteasome-dependent degradation of ACD11, the loss of E3 ubiquitin ligase function enhances the tolerance of salt and drought stress, whereas overexpression increases sensitivity. A model is presented where, upon the perception of abiotic stress, ACD11 abundance increases to promote tolerance. Meanwhile, XBAT35.2 accumulates and in turn promotes the degradation of ACD11 to attenuate the stress response. The results characterize XBAT35.2 as an E3 ubiquitin ligase with opposing roles in abiotic and biotic stress.


Asunto(s)
Proteínas Reguladoras de la Apoptosis/metabolismo , Proteínas de Arabidopsis/fisiología , Arabidopsis/enzimología , Proteínas de Transporte de Membrana/metabolismo , Complejo de la Endopetidasa Proteasomal/metabolismo , Ubiquitina-Proteína Ligasas/fisiología , Ácido Abscísico/metabolismo , Adaptación Fisiológica , Proteínas Reguladoras de la Apoptosis/fisiología , Arabidopsis/metabolismo , Arabidopsis/fisiología , Proteínas de Arabidopsis/metabolismo , Proteínas de Transporte de Membrana/fisiología , Reguladores del Crecimiento de las Plantas/metabolismo , Reguladores del Crecimiento de las Plantas/fisiología , Estrés Salino , Estrés Fisiológico , Ubiquitina-Proteína Ligasas/metabolismo
2.
J Hepatol ; 74(5): 1087-1096, 2021 05.
Artículo en Inglés | MEDLINE | ID: mdl-33276032

RESUMEN

BACKGROUND & AIMS: Intrahepatic cholestasis of pregnancy (ICP) is associated with an increased risk of stillbirth. This study aimed to assess the relationship between bile acid concentrations and fetal cardiac dysfunction in patients with ICP who were or were not treated with ursodeoxycholic acid (UDCA). METHODS: Bile acid profiles and NT-proBNP, a marker of ventricular dysfunction, were assayed in umbilical venous serum from 15 controls and 76 ICP cases (36 untreated, 40 UDCA-treated). Fetal electrocardiogram traces were obtained from 43 controls and 48 ICP cases (26 untreated, 22 UDCA-treated). PR interval length and heart rate variability (HRV) parameters were measured in 2 behavioral states (quiet and active sleep). RESULTS: In untreated ICP, fetal total serum bile acid (TSBA) concentrations (r = 0.49, p = 0.019), hydrophobicity index (r = 0.20, p = 0.039), glycocholate concentrations (r = 0.56, p = 0.007) and taurocholate concentrations (r = 0.44, p = 0.039) positively correlated with fetal NT-proBNP. Maternal TSBA (r = 0.40, p = 0.026) and alanine aminotransferase (r = 0.40, p = 0.046) also positively correlated with fetal NT-proBNP. There were no significant correlations between maternal or fetal serum bile acid concentrations and fetal HRV parameters or NT-proBNP concentrations in the UDCA-treated cohort. Fetal PR interval length positively correlated with maternal TSBA in untreated (r = 0.46, p = 0.027) and UDCA-treated ICP (r = 0.54, p = 0.026). Measures of HRV in active sleep and quiet sleep were significantly higher in untreated ICP cases than controls. HRV values in UDCA-treated cases did not differ from controls. CONCLUSIONS: Elevated fetal and maternal serum bile acid concentrations in untreated ICP are associated with an abnormal fetal cardiac phenotype characterized by increased NT-proBNP concentration, PR interval length and HRV. UDCA treatment partially attenuates this phenotype. LAY SUMMARY: The risk of stillbirth in intrahepatic cholestasis of pregnancy (ICP) is linked to the level of bile acids in the mother which are thought to disrupt the baby's heart rhythm. We found that babies of women with untreated ICP have abnormally functioning hearts compared to those without ICP, and the degree of abnormality is closely linked to the level of harmful bile acids in the mother and baby's blood. Babies of women with ICP who received treatment with the drug UDCA do not have the same level of abnormality in their hearts, suggesting that UDCA could be a beneficial treatment in some ICP cases, although further clinical trials are needed to confirm this.


Asunto(s)
Alanina Transaminasa/sangre , Ácidos y Sales Biliares/sangre , Colestasis Intrahepática , Corazón Fetal/fisiopatología , Péptido Natriurético Encefálico/sangre , Fragmentos de Péptidos/sangre , Complicaciones del Embarazo , Ácido Ursodesoxicólico/uso terapéutico , Disfunción Ventricular , Adulto , Biomarcadores/sangre , Colagogos y Coleréticos/uso terapéutico , Colestasis Intrahepática/sangre , Colestasis Intrahepática/diagnóstico , Colestasis Intrahepática/tratamiento farmacológico , Correlación de Datos , Electrocardiografía/métodos , Femenino , Sangre Fetal , Humanos , Embarazo , Complicaciones del Embarazo/sangre , Complicaciones del Embarazo/diagnóstico , Complicaciones del Embarazo/tratamiento farmacológico , Medición de Riesgo , Mortinato/epidemiología , Resultado del Tratamiento , Disfunción Ventricular/sangre , Disfunción Ventricular/diagnóstico , Disfunción Ventricular/tratamiento farmacológico
3.
Int J Mol Sci ; 22(4)2021 Feb 17.
Artículo en Inglés | MEDLINE | ID: mdl-33671243

RESUMEN

Brown alga Ectocarpus sp. belongs to Phaeophyceae, a class of macroalgae that evolved complex multicellularity. Ectocarpus sp. is a dominant seaweed in temperate regions, abundant mostly in the intertidal zones, an environment with high levels of abiotic stresses. Previous transcriptomic analysis of Ectocarpus sp. revealed several genes consistently induced by various abiotic stresses; one of these genes is Esi0017_0056, which encodes a protein with unknown function. Bioinformatics analyses indicated that the protein encoded by Esi0017_0056 is soluble and monomeric. The protein was successfully expressed in Escherichia coli,Arabidopsis thaliana and Nicotiana benthamiana. In A. thaliana the gene was expressed under constitutive and stress inducible promoters which led to improved tolerance to high salinity and temperature stresses. The expression of several key abiotic stress-related genes was studied in transgenic and wild type A. thaliana by qPCR. Expression analysis revealed that genes involved in ABA-induced abiotic stress tolerance, K+ homeostasis, and chaperon activities were significantly up-regulated in the transgenic line. This study is the first report in which an unknown function Ectocarpus sp. gene, highly responsive to abiotic stresses, was successfully expressed in A. thaliana, leading to improved tolerance to salt and temperature stress.


Asunto(s)
Adaptación Fisiológica , Proteínas Algáceas/metabolismo , Arabidopsis/genética , Arabidopsis/fisiología , Calor , Phaeophyceae/metabolismo , Salinidad , Estrés Fisiológico , Adaptación Fisiológica/genética , Proteínas Algáceas/química , Proteínas Algáceas/genética , Arabidopsis/crecimiento & desarrollo , Electrólitos/metabolismo , Escherichia coli/metabolismo , Regulación de la Expresión Génica de las Plantas , Filogenia , Plantas Modificadas Genéticamente , Regiones Promotoras Genéticas/genética , Plantones/genética , Estrés Fisiológico/genética , Nicotiana/metabolismo
4.
Planta ; 250(4): 1191-1214, 2019 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-31190116

RESUMEN

MAIN CONCLUSION: This study revealed that elevated carbon dioxide increases Arabidopsis tolerance to higher temperature and drought stress by mitigating oxidative stress and improving water status of plants. Few studies have considered multiple aspects of plant responses to key components of global climate change, including higher temperature, elevated carbon dioxide (ECO2), and drought. Hence, their individual and combinatorial effects on plants need to be investigated in the context of understanding climate change impact on plant growth and development. We investigated the interactive effects of temperature, CO2, watering regime, and genotype on Arabidopsis thaliana (WT and ABA-insensitive mutant, abi1-1). Plants were grown in controlled-environment growth chambers under two temperature regimes (22/18 °C and 28/24 °C, 16 h light/8 h dark), two CO2 concentrations (400 and 700 µmol mol-1), and two watering regimes (well-watered and water-stressed) for 18 days. Plant growth, anatomical, physiological, molecular, and hormonal responses were determined. Our study provided valuable information about plant responses to the interactive effects of multiple environmental factors. We showed that drought and ECO2 had larger effects on plants than higher temperatures. ECO2 alleviated the detrimental effects of temperature and drought by mitigating oxidative stress and plant water status, and this positive effect was consistent across multiple response levels. The WT plants performed better than the abi1-1 plants; the former had higher rosette diameter, total dry mass, leaf and soil water potential, leaf moisture, proline, ethylene, trans-zeatin, isopentyladenine, and cis-zeatin riboside than the latter. The water-stressed plants of both genotypes accumulated more abscisic acid (ABA) than the well-watered plants; however, higher temperatures decreased the ability of WT plants to produce ABA in response to drought. We conclude that drought strongly, while higher temperature to a lesser extent, affects Arabidopsis seedlings, and ECO2 reduces the adverse effects of these stressors more efficiently in the WT plants than in the abi1-1 plants. Findings from this study can be extrapolated to other plant species that share similar characteristics and/or family with Arabidopsis.


Asunto(s)
Ácido Abscísico/metabolismo , Proteínas de Arabidopsis/metabolismo , Arabidopsis/fisiología , Dióxido de Carbono/metabolismo , Fosfoproteínas Fosfatasas/metabolismo , Reguladores del Crecimiento de las Plantas/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Cambio Climático , Sequías , Calor , Estrés Oxidativo , Fosfoproteínas Fosfatasas/genética , Suelo/química , Estrés Fisiológico , Agua/fisiología
5.
Plant Mol Biol ; 96(3): 265-278, 2018 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-29270890

RESUMEN

KEY MESSAGE: KEG is involved in mediating the proteasome-dependent degradation of FDH, a stress-responsive enzyme. The UPS may function to suppress FDH mediated stress responses under favorable growth conditions. Formate dehydrogenase (FDH) has been studied in bacteria and yeasts for the purpose of industrial application of NADH co-factor regeneration. In plants, FDH is regarded as a universal stress protein involved in responses to various abiotic and biotic stresses. Here we show that FDH abundance is regulated by the ubiquitin proteasome system (UPS). FDH is ubiquitinated in planta and degraded by the 26S proteasome. Interaction assays identified FDH as a potential substrate for the RING-type ubiquitin ligase Keep on Going (KEG). KEG is capable of attaching ubiquitin to FDH in in vitro assays and the turnover of FDH was increased when co-expressed with a functional KEG in planta, suggesting that KEG contributes to FDH degradation. Consistent with a role in regulating FDH abundance, transgenic plants overexpressing KEG were more sensitive to the inhibitory effects of formate. In addition, FDH is a phosphoprotein and dephosphorylation was found to increase the stability of FDH in degradation assays. Based on results from this and previous studies, we propose a model where KEG mediates the ubiquitination and subsequent degradation of phosphorylated FDH and, in response to unfavourable growth conditions, reduction in FDH phosphorylation levels may prohibit turnover allowing the stabilized FDH to facilitate stress responses.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/fisiología , Plantas Modificadas Genéticamente/metabolismo , Complejo de la Endopetidasa Proteasomal/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Arabidopsis/genética , Arabidopsis/crecimiento & desarrollo , Proteínas de Arabidopsis/genética , Formiatos/metabolismo , Regulación de la Expresión Génica de las Plantas , Fosforilación , Plantas Modificadas Genéticamente/genética , Plantas Modificadas Genéticamente/crecimiento & desarrollo , Complejo de la Endopetidasa Proteasomal/genética , Procesamiento Proteico-Postraduccional , Proteolisis , Estrés Fisiológico , Ubiquitina/metabolismo , Ubiquitina-Proteína Ligasas/genética , Ubiquitinación
6.
Plant Physiol ; 175(3): 1469-1483, 2017 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-28951488

RESUMEN

XBAT35 belongs to a subfamily of Arabidopsis (Arabidopsis thaliana) RING-type E3s that are similar in domain architecture to the rice (Oryza sativa) XA21 Binding Protein3, a defense protein. The XBAT35 transcript undergoes alternative splicing to produce two protein isoforms, XBAT35.1 and XBAT35.2. Here, we demonstrate that XBAT35.2 localizes predominantly to the Golgi and is involved in cell death induction and pathogen response. XBAT35.2, but not XBAT35.1, was found to trigger cell death when overexpressed in tobacco (Nicotiana benthamiana) leaves and does so in a manner that requires its RING domain. Loss of XBAT35 gene function disrupts the plant's ability to defend against pathogen attack, whereas overexpression of XBAT35.2 enhances resistance to pathogens. XBAT35.2 was found to be unstable and promotes its own degradation, suggesting self-regulation. Inoculation with virulent and avirulent strains of the bacterial pathogen Pseudomonas syringae pv tomato DC3000 results in a drastic reduction in the levels of ubiquitinated XBAT35.2 and an increase in the abundance of the E3. This implies that pathogen infection prohibits XBAT35.2 self-regulation and stabilizes the E3. In agreement with a role in defending against pathogens, XBAT35.2 interacts with defense-related Accelerated Cell Death11 (ACD11) in planta and promotes the proteasome-dependent turnover of ACD11 in cell-free degradation assays. In accordance with regulation by a stabilized XBAT35.2, the levels of ubiquitinated ACD11 increased considerably, and the abundance of ACD11 was reduced following pathogen infection. In addition, treatment of transgenic seedlings with a proteasome inhibitor results in the accumulation of ACD11, confirming proteasome-dependent degradation. Collectively, these results highlight a novel role for XBAT35.2 in cell death induction and defense against pathogens.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/citología , Arabidopsis/microbiología , Pseudomonas syringae/fisiología , Ubiquitina-Proteína Ligasas/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Muerte Celular , Resistencia a la Enfermedad , Aparato de Golgi/metabolismo , Células Vegetales/metabolismo , Enfermedades de las Plantas/microbiología , Hojas de la Planta/metabolismo , Plantas Modificadas Genéticamente , Complejo de la Endopetidasa Proteasomal/metabolismo , Unión Proteica , Proteolisis , Pseudomonas syringae/patogenicidad , Dominios RING Finger , Fracciones Subcelulares/metabolismo , Nicotiana/citología , Nicotiana/genética , Ubiquitina-Proteína Ligasas/genética , Ubiquitinación , Virulencia
7.
Plant Physiol ; 169(2): 1405-17, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-26320228

RESUMEN

Jasmonate (JA) signaling in plants is mediated by the JASMONATE ZIM-DOMAIN (JAZ) proteins that repress the activity of several transcription factors regulating JA-inducible gene expression. The hormone JA-isoleucine triggers the interaction of JAZ repressor proteins with the F-box protein CORONATINE INSENSITIVE1 (COI1), part of an S-phase kinase-associated protein1/Cullin1/F-box protein COI1 (SCF(COI1)) E3 ubiquitin ligase complex, and their degradation by the 26S proteasome. In Arabidopsis (Arabidopsis thaliana), the JAZ family consists of 13 members. The level of redundancy or specificity among these members is currently not well understood. Here, we characterized JAZ12, encoded by a highly expressed JAZ gene. JAZ12 interacted with the transcription factors MYC2, MYC3, and MYC4 in vivo and repressed MYC2 activity. Using tandem affinity purification, we found JAZ12 to interact with SCF(COI1) components, matching with observed in vivo ubiquitination and with rapid degradation after treatment with JA. In contrast to the other JAZ proteins, JAZ12 also interacted directly with the E3 RING ligase KEEP ON GOING (KEG), a known repressor of the ABSCISIC ACID INSENSITIVE5 transcription factor in abscisic acid signaling. To study the functional role of this interaction, we circumvented the lethality of keg loss-of-function mutants by silencing KEG using an artificial microRNA approach. Abscisic acid treatment promoted JAZ12 degradation, and KEG knockdown led to a decrease in JAZ12 protein levels. Correspondingly, KEG overexpression was capable of partially inhibiting COI1-mediated JAZ12 degradation. Our results provide additional evidence for KEG as an important factor in plant hormone signaling and a positive regulator of JAZ12 stability.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Proteínas Represoras/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Ácido Abscísico/farmacología , Arabidopsis/efectos de los fármacos , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Factores de Transcripción Básicos con Cremalleras de Leucinas y Motivos Hélice-Asa-Hélice/genética , Factores de Transcripción Básicos con Cremalleras de Leucinas y Motivos Hélice-Asa-Hélice/metabolismo , Regulación de la Expresión Génica de las Plantas , Técnicas de Silenciamiento del Gen , Mutación , Plantas Modificadas Genéticamente , Estabilidad Proteica , Estructura Terciaria de Proteína , Proteínas Represoras/genética , Nicotiana/genética , Ubiquitina-Proteína Ligasas/genética
8.
J Biol Chem ; 288(28): 20267-79, 2013 Jul 12.
Artículo en Inglés | MEDLINE | ID: mdl-23720747

RESUMEN

To mitigate the effects of environmental stress the abscisic acid (ABA)-responsive transcription factor ABI5 is required to delay growth of germinated seedlings. In the absence of stress, KEEP ON GOING (KEG) E3 is required to maintain low levels of ABI5. However, the mechanism underlying KEG-dependent turnover of ABI5 is not known. In addition, localization studies place KEG at the trans-Golgi network, whereas ABI5 is nuclear. Here we show that KEG interacts directly with ABI5 via its conserved C3 region. Interactions between KEG and ABI5 were observed in the cytoplasm and trans-Golgi network only when the RING domain of KEG was inactivated or when ABI5 was stabilized via mutations. Deletion of the C-terminal region of ABI5 or substituting lysine 344 for alanine (K344A) prohibited protein turnover. Furthermore, ABI5 is observed in the cytoplasm of Arabidopsis thaliana root cells when the K344A mutation is combined with the deletion of a nuclear localization signal. Other lysine mutations (K353A, K364A, and K376A) in conjunction with the nuclear localization signal deletion did not result in cytoplasmic accumulation of ABI5. Loss of lysine 344 did not affect the ability of ABI5 to promote ABA responses, which demonstrates that the mutant transcription factor is still functional. Based on the results, a model is suggested where KEG targets ABI5 for degradation in the cytoplasm, thus reducing nuclear accumulation of the transcription factor in the absence of ABA.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/metabolismo , Citoplasma/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Ácido Abscísico/farmacología , Alanina/genética , Alanina/metabolismo , Sustitución de Aminoácidos , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/genética , Immunoblotting , Proteínas Luminiscentes/genética , Proteínas Luminiscentes/metabolismo , Lisina/genética , Lisina/metabolismo , Microscopía Confocal , Mutación , Señales de Localización Nuclear/genética , Plantas Modificadas Genéticamente , Unión Proteica , Proteolisis , Plantones/efectos de los fármacos , Plantones/genética , Plantones/metabolismo , Ubiquitina-Proteína Ligasas/genética , Red trans-Golgi/metabolismo
9.
Plant J ; 75(6): 965-76, 2013 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-23742014

RESUMEN

The ABA Binding Factor/ABA-Responsive Element Binding Proteins (ABF/AREB) subfamily of bZIP-type transcription factors are positive effectors of ABA responses. Here, we examine the proteolytic regulation of two members: Arabidopsis thaliana ABF1 and ABF3. Both transcription factors are unstable in seedlings, and their degradation is sensitive to proteasome inhibition. ABA treatment of seedlings leads to their rapid accumulation, the result of slowed proteolysis. Deletion of the conserved C-terminal region required for 14-3-3 interaction destabilizes the proteins. The degradation of ABF1 and ABF3 are slower in vivo in seedlings lacking the ubiquitin E3 ligase KEEP ON GOING (KEG), and in vitro in extracts from keg seedlings, implicating KEG in their degradation. ABF1 and ABF3 are ubiquitylation substrates of KEG in vitro, and in vitro pull-down assays document their direct interaction. In contrast to ABI5, another KEG substrate, the degradation of ABFs and proteolytic regulation of ABFs by ABA still occurs in keg seedlings, suggesting that additional E3s participate in ABF1 and ABF3 proteolysis. Loss of ABF1 or ABF3 in the keg background has a phenotypic effect similar to the loss of ABI5, and there is no additional rescue of the keg phenotype in abf1 abf3 abi5 keg seedlings. This result suggests that the abundance of other substrates is altered in keg seedlings, affecting growth. In conclusion, ABF1 and ABF3 abundance is affected by ABA and KEG, and the conserved C4 region serves as a stabilizing element.


Asunto(s)
Ácido Abscísico/metabolismo , Proteínas de Arabidopsis/metabolismo , Arabidopsis/fisiología , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Ubiquitinación , Secuencia de Aminoácidos , Secuencia Conservada , Fenotipo , Inhibidores de Proteasoma , Proteolisis , Plantones/metabolismo
10.
Plant J ; 71(1): 23-34, 2012 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-22339729

RESUMEN

E3 ubiquitin ligases select specific proteins for ubiquitin conjugation, and the modified proteins are commonly degraded through the 26S proteasome. XBAT32 is a RING-type E3 ligase involved in maintaining appropriate levels of ethylene. Previous work has suggested that XBAT32 modulates ethylene production by ubiquitinating two ethylene biosynthesis enzymes, ACS4 (type-II isoform) and ACS7 (type-III isoform). In Arabidopsis, conserved sequences within the C-terminal tail of type-I and -II 1-aminocyclopropane-1-carboxylate (ACC) synthase (ACS) isoforms influence ubiquitin-dependent proteolysis. ACS7, the sole Arabidopsis type-III ACS, contains a truncated C-terminal tail that lacks all known regulatory sequences, which suggests that this isoform may not be subject to ubiquitin-mediated proteasomal degradation. Here we demonstrate in planta that ACS7 is turned over in a 26S proteasome-dependent manner and that degradation of ACS7 requires the E3 ligase XBAT32. Furthermore, the ethylene-related phenotypes that result from overexpression of ACS7 in wild-type plants are greatly exaggerated in xbat32-1, suggesting that XBAT32 is required to attenuate the effect of overexpression of ACS7. This observation is consistent with a role for XBAT32 in the ubiquitin-mediated degradation of ACS7. The dark-grown phenotype of xbat32-1 seedlings overexpressing ACS7 can be effectively rescued by aminoethoxyvinylglycine, an inhibitor of ACS activity. The degradation rate of ACS4 is also significantly slower in the absence of XBAT32, further implicating XBAT32 in the ubiquitin-mediated degradation of ACS4. Altogether, these results demonstrate that XBAT32 targets ethylene biosynthetic enzymes for proteasomal degradation to maintain appropriate levels of hormone production.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/enzimología , Liasas/metabolismo , Complejo de la Endopetidasa Proteasomal/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Secuencia de Aminoácidos , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Regulación de la Expresión Génica de las Plantas , Liasas/genética , Datos de Secuencia Molecular , Mutagénesis Insercional , Ubiquitina-Proteína Ligasas/genética
11.
BMC Plant Biol ; 13: 107, 2013 Jul 29.
Artículo en Inglés | MEDLINE | ID: mdl-23890153

RESUMEN

BACKGROUND: Plants have evolved an array of constitutive and inducible defense strategies to restrict pathogen ingress. However, some pathogens still manage to invade plants and impair growth and productivity. Previous studies have revealed several key regulators of defense responses, and efforts have been made to use this information to develop disease resistant crop plants. These efforts are often hampered by the complexity of defense signaling pathways. To further elucidate the complexity of defense responses, we screened a population of T-DNA mutants in Colombia-0 background that displayed altered defense responses to virulent Pseudomonas syringae pv. tomato DC3000 (Pst DC3000). RESULTS: In this study, we demonstrated that the Arabidopsis Purple Acid Phosphatse5 (PAP5) gene, induced under prolonged phosphate (Pi) starvation, is required for maintaining basal resistance to certain pathogens. The expression of PAP5 was distinctly induced only under prolonged Pi starvation and during the early stage of Pst DC3000 infection (6 h.p.i). T-DNA tagged mutant pap5 displayed enhanced susceptibility to the virulent bacterial pathogen Pst DC3000. The pap5 mutation greatly reduced the expression of pathogen inducible gene PR1 compared to wild-type plants. Similarly, other defense related genes including ICS1 and PDF1.2 were impaired in pap5 plants. Moreover, application of BTH (an analog of SA) restored PR1 expression in pap5 plants. CONCLUSION: Taken together, our results demonstrate the requirement of PAP5 for maintaining basal resistance against Pst DC3000. Furthermore, our results provide evidence that PAP5 acts upstream of SA accumulation to regulate the expression of other defense responsive genes. We also provide the first experimental evidence indicating the role PAP5 in plant defense responses.


Asunto(s)
Fosfatasa Ácida/metabolismo , Proteínas de Arabidopsis/metabolismo , Arabidopsis/enzimología , Resistencia a la Enfermedad , Glicoproteínas/metabolismo , Enfermedades de las Plantas , Pseudomonas syringae , Fosfatasa Ácida/genética , Arabidopsis/genética , Arabidopsis/microbiología , Proteínas de Arabidopsis/genética , ADN Bacteriano/genética , Regulación de la Expresión Génica de las Plantas , Glicoproteínas/genética , Mutagénesis Insercional , Enfermedades de las Plantas/microbiología
12.
J Exp Bot ; 64(10): 2779-91, 2013 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-23658427

RESUMEN

The RING-type E3 ligase, Keep on Going (KEG), is required for early seedling establishment in Arabidopsis thaliana. Post-germination, KEG negatively regulates abscisic acid (ABA) signalling by targeting Abscisic Acid Insensitive 5 (ABI5) for ubiquitination and subsequent degradation. Previous reports suggest that the role of KEG during early seedling development is not limited to regulation of ABI5 abundance. Using a yeast two-hybrid screen, this study identified Calcineurin B-like Interacting Protein Kinase (CIPK) 26 as a KEG-interacting protein. In vitro pull-down and in planta bimolecular fluorescence complementation assays confirmed the interactions between CIPK26 and KEG. In planta experiments demonstrated that CIPK26 was ubiquitinated and degraded via the 26S proteasome. It was also found that turnover of CIPK26 was increased when KEG protein levels were elevated, suggesting that the RING-type E3 ligase is involved in targeting CIPK26 for degradation. CIPK26 was found to interact with the ABA signalling components ABI1, ABI2, and ABI5. In addition, CIPK26 was capable of phosphorylating ABI5 in vitro. Consistent with a role in ABA signalling, overexpression of CIPK26 increased the sensitivity of germinating seeds to the inhibitory effects of ABA. The data presented in this report suggest that KEG mediates the proteasomal degradation of CIPK26 and that CIPK26 is part of the ABA signalling network.


Asunto(s)
Ácido Abscísico/metabolismo , Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Complejo de la Endopetidasa Proteasomal/metabolismo , Proteínas Quinasas/metabolismo , Transducción de Señal , Ubiquitina-Proteína Ligasas/metabolismo , Ubiquitina/metabolismo , Arabidopsis/enzimología , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Regulación de la Expresión Génica de las Plantas , Fosforilación , Complejo de la Endopetidasa Proteasomal/genética , Unión Proteica , Proteínas Quinasas/genética , Proteolisis , Ubiquitina-Proteína Ligasas/genética , Ubiquitinación
13.
Plant Cell ; 22(8): 2630-41, 2010 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-20682837

RESUMEN

The Arabidopsis thaliana RING-type E3 ligase KEEP ON GOING (KEG) is a negative regulator of abscisic acid (ABA) signaling. Seedlings homozygous for T-DNA insertions in KEG accumulate high levels of the ABA-responsive transcription factor ABSCISIC ACID-INSENSITIVE5 (ABI5). Here, we demonstrate that KEG E3 ligase activity is required for the regulation of ABI5 abundance. KEG ubiquitinates ABI5 in vitro, and a functional KEG RING domain is required to restore the levels of ABI5 in keg-1 to that of the wild type. Overexpression of KEG leads to ABA insensitivity, which correlates with KEG protein levels. In the presence of ABA, ABI5 levels increase drastically via a decrease in ubiquitin-meditated proteasomal degradation. Our results indicate that ABA promotes ABI5 accumulation by inducing the ubiquitination and proteasomal degradation of KEG. A functional RING domain is required for the ABA-induced degradation of KEG, suggesting that the loss is due to self-ubiquitination. Mutations within KEG's kinase domain or treatments with kinase inhibitors prohibit the ABA-induced ubiquitination and degradation of KEG, indicating that phosphorylation, possibly self-phosphorylation, is involved in the ABA regulation of KEG protein levels. We discuss a model for how ABA may negatively regulate KEG protein abundance, leading to accumulation of ABI5 and ABA-dependent cellular responses.


Asunto(s)
Ácido Abscísico/farmacología , Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/metabolismo , Complejo de la Endopetidasa Proteasomal/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Arabidopsis/enzimología , Proteínas de Arabidopsis/genética , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/genética , Regulación de la Expresión Génica de las Plantas , Mutagénesis Sitio-Dirigida , Fosforilación , Plantas Modificadas Genéticamente/enzimología , Plantas Modificadas Genéticamente/genética , Procesamiento Proteico-Postraduccional , Ubiquitina-Proteína Ligasas/genética , Ubiquitinación
14.
Minerva Obstet Gynecol ; 75(3): 251-259, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-37183772

RESUMEN

BACKGROUND: Obesity can negatively influence quality of life (QoL). Polycystic ovarian syndrome (PCOS), associated with obesity, presents with sub-fertility, hyperandrogenism, and/or insulin resistance. These features can also negatively influence QoL. This study aimed to determine whether bariatric surgery improves QoL in women of reproductive age, with and without PCOS. We hypothesized greater QoL improvements would be seen post-operatively in women with PCOS. METHODS: Women undergoing bariatric surgery (N.=77) completed questionnaires exploring health-related quality of life (HR-QoL) prior to and at 3, 6 and 12 months post-surgery. Weight loss, symptoms, and association with change in QoL were assessed. RESULTS: Bariatric surgery resulted in significant QoL improvements, independent of PCOS status. Oligo/amenorrhea was reported in 68% of women at baseline, decreasing to 35% by 12 months. Sixty-five percent of women whose menstrual irregularity resolved over follow-up had PCOS. Hirsutism was reported in 64% of women at baseline (all of whom had PCOS), decreasing to 19% by 12 months. Weight loss at 12-months was 45.8±20.7 kg for women without PCOS compared to 44.3±16.8 kg in women with PCOS (P=0.07). Weight loss was moderately associated with 12-month QoL improvements for both groups. CONCLUSIONS: Bariatric surgery provides significant physical and psychological health benefits for women with obesity both with and without PCOS. Surgery can also ameliorate the clinical syndrome of PCOS, including oligomenorrhoea, hirsutism, and subfertility, with subsequent QoL benefits. Psychological support perioperatively may aid QoL outcomes by acknowledging factors influencing QoL beside absolute weight loss.


Asunto(s)
Cirugía Bariátrica , Obesidad , Síndrome del Ovario Poliquístico , Femenino , Humanos , Cirugía Bariátrica/psicología , Estudios de Cohortes , Obesidad/complicaciones , Obesidad/cirugía , Síndrome del Ovario Poliquístico/complicaciones , Síndrome del Ovario Poliquístico/cirugía , Síndrome del Ovario Poliquístico/psicología , Calidad de Vida
15.
J Exp Bot ; 63(2): 599-616, 2012 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-22016431

RESUMEN

Plant growth and development is largely influenced by ubiquitin-mediated regulation of protein stability. Specificity of the ubiquitination pathway is controlled mainly by the substrate-recruiting E3 ubiquitin ligases, and consequently, E3 ligases control numerous cellular processes. Recent evidence that ubiquitination plays a critical role in regulating plant responses to abiotic stresses has launched intensive efforts to identify E3 ligases that mediate plant tolerance of adverse environmental conditions. Most stress-related E3 ligases identified to date facilitate responses to environmental stimuli by modulating the abundance of key downstream stress-responsive transcription factors. In this review, the regulatory roles of ubiquitin during the plant's response to abiotic stress are summarized and highlighted.


Asunto(s)
Adaptación Fisiológica/fisiología , Proteínas de Plantas/metabolismo , Plantas/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Ubiquitinación/fisiología , Ácido Abscísico/metabolismo , Regulación de la Expresión Génica de las Plantas/fisiología , Complejo de la Endopetidasa Proteasomal/metabolismo , Estabilidad Proteica , Transducción de Señal/fisiología , Estrés Fisiológico/fisiología , Factores de Transcripción/genética , Factores de Transcripción/metabolismo
16.
Plant Cell ; 21(9): 2655-71, 2009 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-19789280

RESUMEN

In the Brassicaceae, compatible pollen-pistil interactions result in pollen adhesion to the stigma, while pollen grains from unrelated plant species are largely ignored. There can also be an additional layer of recognition to prevent self-fertilization, the self-incompatibility response, whereby self pollen grains are distinguished from nonself pollen grains and rejected. This pathway is activated in the stigma and involves the ARM repeat-containing 1 (ARC1) protein, an E3 ubiquitin ligase. In a screen for ARC1-interacting proteins, we have identified Brassica napus Exo70A1, a putative component of the exocyst complex that is known to regulate polarized secretion. We show through transgenic studies that loss of Exo70A1 in Brassica and Arabidopsis thaliana stigmas leads to the rejection of compatible pollen at the same stage as the self-incompatibility response. A red fluorescent protein:Exo70A1 fusion rescues this stigmatic defect in Arabidopsis and is found to be mobilized to the plasma membrane concomitant with flowers opening. By contrast, increased expression of Exo70A1 in self-incompatible Brassica partially overcomes the self pollen rejection response. Thus, our data show that the Exo70A1 protein functions at the intersection of two cellular pathways, where it is required in the stigma for the acceptance of compatible pollen in both Brassica and Arabidopsis and is negatively regulated by Brassica self-incompatibility.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Brassica/genética , Endogamia , Polen/metabolismo , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Brassica/metabolismo , Células Cultivadas , ADN Bacteriano/genética , Regulación de la Expresión Génica de las Plantas , Datos de Secuencia Molecular , Mutagénesis Insercional , Plantas Modificadas Genéticamente/genética , Plantas Modificadas Genéticamente/metabolismo , Polen/genética , Interferencia de ARN , Nicotiana/genética , Nicotiana/metabolismo , Técnicas del Sistema de Dos Híbridos
17.
Essays Biochem ; 66(2): 123-133, 2022 08 05.
Artículo en Inglés | MEDLINE | ID: mdl-35704617

RESUMEN

Plants must cope with an ever-changing environment, including concurrent biotic and abiotic stresses. The ubiquitin-proteasome system (UPS) is intricately involved in regulating signaling events that facilitate cellular changes required to mitigate the detrimental effects of environmental stress. A key component of the UPS are ubiquitin ligases (or E3s) that catalyze the attachment of ubiquitin molecules to select substrate proteins, which are then recognized by the 26S proteasome for degradation. With the identification of substrate proteins, a growing number of E3s are shown to differentially regulate responses to abiotic as well as bioitic stresses. The review discusses select E3s to illustrate the role of ubiquitin ligases as negative and/or positive regulators of responses to both biotic and abiotic stresses.


Asunto(s)
Ubiquitina-Proteína Ligasas , Ubiquitina , Plantas/metabolismo , Transducción de Señal , Estrés Fisiológico , Ubiquitina/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo
18.
Front Plant Sci ; 13: 867419, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35665152

RESUMEN

Plants utilize different molecular mechanisms, including the Ubiquitin Proteasome System (UPS) that facilitates changes to the proteome, to mitigate the impact of abiotic stresses on growth and development. The UPS encompasses the ubiquitination of selected substrates followed by the proteasomal degradation of the modified proteins. Ubiquitin ligases, or E3s, are central to the UPS as they govern specificity and facilitate the attachment of one or more ubiquitin molecules to the substrate protein. From recent studies, the UPS has emerged as an important regulator of the uptake and translocation of essential macronutrients and micronutrients. In this review, we discuss select E3s that are involved in regulating nutrient uptake and responses to stress conditions, including limited or excess levels of nitrogen, phosphorus, iron, and copper.

19.
Ecol Evol ; 12(4): e8797, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-35475182

RESUMEN

The interface between field biology and technology is energizing the collection of vast quantities of environmental data. Passive acoustic monitoring, the use of unattended recording devices to capture environmental sound, is an example where technological advances have facilitated an influx of data that routinely exceeds the capacity for analysis. Computational advances, particularly the integration of machine learning approaches, will support data extraction efforts. However, the analysis and interpretation of these data will require parallel growth in conceptual and technical approaches for data analysis. Here, we use a large hand-annotated dataset to showcase analysis approaches that will become increasingly useful as datasets grow and data extraction can be partially automated.We propose and demonstrate seven technical approaches for analyzing bioacoustic data. These include the following: (1) generating species lists and descriptions of vocal variation, (2) assessing how abiotic factors (e.g., rain and wind) impact vocalization rates, (3) testing for differences in community vocalization activity across sites and habitat types, (4) quantifying the phenology of vocal activity, (5) testing for spatiotemporal correlations in vocalizations within species, (6) among species, and (7) using rarefaction analysis to quantify diversity and optimize bioacoustic sampling.To demonstrate these approaches, we sampled in 2016 and 2018 and used hand annotations of 129,866 bird vocalizations from two forests in New Hampshire, USA, including sites in the Hubbard Brook Experiment Forest where bioacoustic data could be integrated with more than 50 years of observer-based avian studies. Acoustic monitoring revealed differences in community patterns in vocalization activity between forests of different ages, as well as between nearby similar watersheds. Of numerous environmental variables that were evaluated, background noise was most clearly related to vocalization rates. The songbird community included one cluster of species where vocalization rates declined as ambient noise increased and another cluster where vocalization rates declined over the nesting season. In some common species, the number of vocalizations produced per day was correlated at scales of up to 15 km. Rarefaction analyses showed that adding sampling sites increased species detections more than adding sampling days.Although our analyses used hand-annotated data, the methods will extend readily to large-scale automated detection of vocalization events. Such data are likely to become increasingly available as autonomous recording units become more advanced, affordable, and power efficient. Passive acoustic monitoring with human or automated identification at the species level offers growing potential to complement observer-based studies of avian ecology.

20.
Plant Physiol ; 153(4): 1587-96, 2010 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-20511490

RESUMEN

XBAT32, a member of the RING domain-containing ankyrin repeat subfamily of E3 ligases, was previously identified as a positive regulator of lateral root development. Arabidopsis (Arabidopsis thaliana) plants harboring a mutation in XBAT32 produce fewer lateral roots that wild-type plants. We found that xbat32 mutants produce significantly more ethylene than wild-type plants and that inhibition of ethylene biosynthesis or perception significantly increased xbat32 lateral root production. XBAT32 interacts with the ethylene biosynthesis enzymes AMINOCYCLOPROPANE-1-CARBOXYLIC ACID SYNTHASE4 (ACS4) and ACS7 in yeast-two-hybrid assays. XBAT32 is capable of catalyzing the attachment of ubiquitin to both ACS4 and ACS7 in in vitro ubiquitination assays. These results suggest that XBAT32 negatively regulates ethylene biosynthesis by modulating the abundance of ACS proteins. Loss of XBAT32 may promote the stabilization of ACSs and lead to increased ethylene synthesis and suppression of lateral root formation. XBAT32 may also contribute to the broader hormonal cross talk that influences lateral root development. While auxin treatments only partially rescue the lateral root defect of xbat32, they completely restore wild-type levels of xbat32 lateral root production when coupled with ethylene inhibition. Abscisic acid, an antagonist of ethylene synthesis/signaling, was also found to stimulate rather than inhibit xbat32 lateral root formation, and abscisic acid acts synergistically with auxin to promote xbat32 lateral root production.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/enzimología , Etilenos/biosíntesis , Raíces de Plantas/crecimiento & desarrollo , Ubiquitina-Proteína Ligasas/metabolismo , Ácido Abscísico/farmacología , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Regulación de la Expresión Génica de las Plantas , Liasas/metabolismo , Mutagénesis Insercional , Mutación , Técnicas del Sistema de Dos Híbridos , Ubiquitina-Proteína Ligasas/genética , Ubiquitinación
SELECCIÓN DE REFERENCIAS
Detalles de la búsqueda