Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 68
Filtrar
Más filtros

Banco de datos
Tipo del documento
Intervalo de año de publicación
1.
Cell ; 156(3): 577-89, 2014 Jan 30.
Artículo en Inglés | MEDLINE | ID: mdl-24485461

RESUMEN

Auxin regulates numerous plant developmental processes by controlling gene expression via a family of functionally distinct DNA-binding auxin response factors (ARFs), yet the mechanistic basis for generating specificity in auxin response is unknown. Here, we address this question by solving high-resolution crystal structures of the pivotal Arabidopsis developmental regulator ARF5/MONOPTEROS (MP), its divergent paralog ARF1, and a complex of ARF1 and a generic auxin response DNA element (AuxRE). We show that ARF DNA-binding domains also homodimerize to generate cooperative DNA binding, which is critical for in vivo ARF5/MP function. Strikingly, DNA-contacting residues are conserved between ARFs, and we discover that monomers have the same intrinsic specificity. ARF1 and ARF5 homodimers, however, differ in spacing tolerated between binding sites. Our data identify the DNA-binding domain as an ARF dimerization domain, suggest that ARF dimers bind complex sites as molecular calipers with ARF-specific spacing preference, and provide an atomic-scale mechanistic model for specificity in auxin response.


Asunto(s)
Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Proteínas de Unión al ADN/química , Proteínas de Unión al ADN/metabolismo , ADN/metabolismo , Ácidos Indolacéticos/metabolismo , Factores de Transcripción/química , Factores de Transcripción/metabolismo , Secuencia de Aminoácidos , Cristalografía por Rayos X , ADN/química , Dimerización , Modelos Moleculares , Datos de Secuencia Molecular , Filogenia , Estructura Terciaria de Proteína , Alineación de Secuencia
2.
Nature ; 563(7732): 574-578, 2018 11.
Artículo en Inglés | MEDLINE | ID: mdl-30429609

RESUMEN

Stomatal cell lineage is an archetypal example of asymmetric cell division (ACD), which is necessary for plant survival1-4. In Arabidopsis thaliana, the GLYCOGEN SYNTHASE KINASE3 (GSK3)/SHAGGY-like kinase BRASSINOSTEROID INSENSITIVE 2 (BIN2) phosphorylates both the mitogen-activated protein kinase (MAPK) signalling module5,6 and its downstream target, the transcription factor SPEECHLESS (SPCH)7, to promote and restrict ACDs, respectively, in the same stomatal lineage cell. However, the mechanisms that balance these mutually exclusive activities remain unclear. Here we identify the plant-specific protein POLAR as a stomatal lineage scaffold for a subset of GSK3-like kinases that confines them to the cytosol and subsequently transiently polarizes them within the cell, together with BREAKING OF ASYMMETRY IN THE STOMATAL LINEAGE (BASL), before ACD. As a result, MAPK signalling is attenuated, enabling SPCH to drive ACD in the nucleus. Moreover, POLAR turnover requires phosphorylation on specific residues, mediated by GSK3. Our study reveals a mechanism by which the scaffolding protein POLAR ensures GSK3 substrate specificity, and could serve as a paradigm for understanding regulation of GSK3 in plants.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/citología , Arabidopsis/metabolismo , División Celular Asimétrica , Proteínas de Ciclo Celular/metabolismo , Polaridad Celular , Complejos Multiproteicos/metabolismo , Transducción de Señal , Arabidopsis/enzimología , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Linaje de la Célula , Citosol/enzimología , Citosol/metabolismo , Glucógeno Sintasa Quinasa 3/metabolismo , Sistema de Señalización de MAP Quinasas , Complejos Multiproteicos/química , Fenotipo , Fosforilación , Estomas de Plantas/citología , Unión Proteica , Proteínas Quinasas/metabolismo , Especificidad por Sustrato
3.
Development ; 147(13)2020 07 08.
Artículo en Inglés | MEDLINE | ID: mdl-32554529

RESUMEN

In many flowering plants, asymmetric division of the zygote generates apical and basal cells with different fates. In Arabidopsis thaliana, the apical cell generates the embryo while the basal cell divides anticlinally, leading to a suspensor of six to nine cells that remain extra-embryonic and eventually senesce. In some genetic backgrounds, or upon ablation of the embryo, suspensor cells can undergo periclinal cell divisions and eventually form a second twin embryo. Likewise, embryogenesis can be induced from somatic cells by various genes, but the relationship with suspensor-derived embryos is unclear. Here, we addressed the nature of the suspensor to embryo fate transformation and its genetic triggers. We expressed most known embryogenesis-inducing genes specifically in suspensor cells. We next analyzed morphology and fate-marker expression in embryos in which suspensor division was activated by different triggers to address the developmental paths towards reprogramming. Our results show that reprogramming of Arabidopsis suspensor cells towards embryonic identity is a specific cellular response that is triggered by defined regulators, follows a conserved developmental trajectory and shares similarity to the process of somatic embryogenesis from post-embryonic tissues.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Semillas/metabolismo , Arabidopsis/genética , Arabidopsis/fisiología , Proteínas de Arabidopsis/genética , Reprogramación Celular/genética , Reprogramación Celular/fisiología , Regulación de la Expresión Génica de las Plantas/genética , Regulación de la Expresión Génica de las Plantas/fisiología , Semillas/genética
4.
Plant Cell ; 30(10): 2573-2593, 2018 10.
Artículo en Inglés | MEDLINE | ID: mdl-30018157

RESUMEN

Small GTP-binding proteins from the ADP-ribosylation factor (ARF) family are important regulators of vesicle formation and cellular trafficking in all eukaryotes. ARF activation is accomplished by a protein family of guanine nucleotide exchange factors (GEFs) that contain a conserved catalytic Sec7 domain. Here, we identified and characterized Secdin, a small-molecule inhibitor of Arabidopsis thaliana ARF-GEFs. Secdin application caused aberrant retention of plasma membrane (PM) proteins in late endosomal compartments, enhanced vacuolar degradation, impaired protein recycling, and delayed secretion and endocytosis. Combined treatments with Secdin and the known ARF-GEF inhibitor Brefeldin A (BFA) prevented the BFA-induced PM stabilization of the ARF-GEF GNOM, impaired its translocation from the Golgi to the trans-Golgi network/early endosomes, and led to the formation of hybrid endomembrane compartments reminiscent of those in ARF-GEF-deficient mutants. Drug affinity-responsive target stability assays revealed that Secdin, unlike BFA, targeted all examined Arabidopsis ARF-GEFs, but that the interaction was probably not mediated by the Sec7 domain because Secdin did not interfere with the Sec7 domain-mediated ARF activation. These results show that Secdin and BFA affect their protein targets through distinct mechanisms, in turn showing the usefulness of Secdin in studies in which ARF-GEF-dependent endomembrane transport cannot be manipulated with BFA.


Asunto(s)
Arabidopsis/efectos de los fármacos , Factores de Intercambio de Guanina Nucleótido/antagonistas & inhibidores , Ftalazinas/farmacología , Piperazinas/farmacología , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Brefeldino A/farmacología , Endocitosis/efectos de los fármacos , Endosomas/efectos de los fármacos , Endosomas/metabolismo , Factores de Intercambio de Guanina Nucleótido/genética , Factores de Intercambio de Guanina Nucleótido/metabolismo , Plantas Modificadas Genéticamente , Proteínas Quinasas/genética , Proteínas Quinasas/metabolismo , Transporte de Proteínas , Vacuolas/efectos de los fármacos , Vacuolas/metabolismo
5.
Plant Cell ; 29(9): 2285-2303, 2017 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-28842532

RESUMEN

BAK1 is a coreceptor and positive regulator of multiple ligand binding leucine-rich repeat receptor kinases (LRR-RKs) and is involved in brassinosteroid (BR)-dependent growth and development, innate immunity, and cell death control. The BAK1-interacting LRR-RKs BIR2 and BIR3 were previously identified by proteomics analyses of in vivo BAK1 complexes. Here, we show that BAK1-related pathways such as innate immunity and cell death control are affected by BIR3 in Arabidopsis thaliana BIR3 also has a strong negative impact on BR signaling. BIR3 directly interacts with the BR receptor BRI1 and other ligand binding receptors and negatively regulates BR signaling by competitive inhibition of BRI1. BIR3 is released from BAK1 and BRI1 after ligand exposure and directly affects the formation of BAK1 complexes with BRI1 or FLAGELLIN SENSING2. Double mutants of bak1 and bir3 show spontaneous cell death and constitutive activation of defense responses. BAK1 and its closest homolog BKK1 interact with and are stabilized by BIR3, suggesting that bak1 bir3 double mutants mimic the spontaneous cell death phenotype observed in bak1 bkk1 mutants via destabilization of BIR3 target proteins. Our results provide evidence for a negative regulatory mechanism for BAK1 receptor complexes in which BIR3 interacts with BAK1 and inhibits ligand binding receptors to prevent BAK1 receptor complex formation.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Proteínas de la Membrana/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas/metabolismo , Arabidopsis/efectos de los fármacos , Brasinoesteroides/metabolismo , Muerte Celular/efectos de los fármacos , Flagelina/farmacología , Proteínas Repetidas Ricas en Leucina , Ligandos , Mutación/genética , Moléculas de Patrón Molecular Asociado a Patógenos/metabolismo , Fenotipo , Unión Proteica/efectos de los fármacos , Estabilidad Proteica/efectos de los fármacos , Transducción de Señal
7.
Plant Physiol ; 172(4): 2516-2529, 2016 12.
Artículo en Inglés | MEDLINE | ID: mdl-27803191

RESUMEN

Somatic embryogenesis receptor kinases (SERKs) are ligand-binding coreceptors that are able to combine with different ligand-perceiving receptors such as BRASSINOSTEROID INSENSITIVE1 (BRI1) and FLAGELLIN-SENSITIVE2. Phenotypical analysis of serk single mutants is not straightforward because multiple pathways can be affected, while redundancy is observed for a single phenotype. For example, serk1serk3 double mutant roots are insensitive toward brassinosteroids but have a phenotype different from bri1 mutant roots. To decipher these effects, 4-d-old Arabidopsis (Arabidopsis thaliana) roots were studied using microarray analysis. A total of 698 genes, involved in multiple biological processes, were found to be differentially regulated in serk1-3serk3-2 double mutants. About half of these are related to brassinosteroid signaling. The remainder appear to be unlinked to brassinosteroids and related to primary and secondary metabolism. In addition, methionine-derived glucosinolate biosynthesis genes are up-regulated, which was verified by metabolite profiling. The results also show that the gene expression pattern in serk3-2 mutant roots is similar to that of the serk1-3serk3-2 double mutant roots. This confirms the existence of partial redundancy between SERK3 and SERK1 as well as the promoting or repressive activity of a single coreceptor in multiple simultaneously active pathways.


Asunto(s)
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Regulación de la Expresión Génica de las Plantas , Mutación/genética , Proteínas Quinasas/genética , Proteínas Serina-Treonina Quinasas/genética , Transcripción Genética , Alelos , Brasinoesteroides/metabolismo , Perfilación de la Expresión Génica , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Glucosinolatos/farmacología , Metaboloma/efectos de los fármacos , Análisis Multivariante , Fenotipo , Raíces de Plantas/efectos de los fármacos , Raíces de Plantas/genética , Transcripción Genética/efectos de los fármacos
8.
Plant Cell ; 25(9): 3377-88, 2013 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-24064770

RESUMEN

Brassinosteroid (BR) hormones are primarily perceived at the cell surface by the leucine-rich repeat receptor-like kinase brassinosteroid insensitive1 (BRI1). In Arabidopsis thaliana, BRI1 has two close homologs, BRI1-LIKE1 (BRL1) and BRL3, respectively, which are expressed in the vascular tissues and regulate shoot vascular development. Here, we identify novel components of the BRL3 receptor complex in planta by immunoprecipitation and mass spectrometry analysis. Whereas BRI1 associated kinase1 (BAK1) and several other known BRI1 interactors coimmunoprecipitated with BRL3, no evidence was found of a direct interaction between BRI1 and BRL3. In addition, we confirmed that BAK1 interacts with the BRL1 receptor by coimmunoprecipitation and fluorescence microscopy analysis. Importantly, genetic analysis of brl1 brl3 bak1-3 triple mutants revealed that BAK1, BRL1, and BRL3 signaling modulate root growth and development by contributing to the cellular activities of provascular and quiescent center cells. This provides functional relevance to the observed protein-protein interactions of the BRL3 signalosome. Overall, our study demonstrates that cell-specific BR receptor complexes can be assembled to perform different cellular activities during plant root growth, while highlighting that immunoprecipitation of leucine-rich repeat receptor kinases in plants is a powerful approach for unveiling signaling mechanisms with cellular resolution in plant development.


Asunto(s)
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Regulación de la Expresión Génica de las Plantas , Proteínas Serina-Treonina Quinasas/genética , Receptores de Superficie Celular/genética , Transducción de Señal , Arabidopsis/citología , Arabidopsis/crecimiento & desarrollo , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Brasinoesteroides/metabolismo , Ciclo Celular , Cromatografía Liquida , Genes Reporteros , Complejos Multiproteicos , Mutación , Fenotipo , Floema/citología , Floema/genética , Floema/crecimiento & desarrollo , Floema/metabolismo , Raíces de Plantas/citología , Raíces de Plantas/genética , Raíces de Plantas/crecimiento & desarrollo , Raíces de Plantas/metabolismo , Plantas Modificadas Genéticamente , Mapeo de Interacción de Proteínas , Proteínas Serina-Treonina Quinasas/metabolismo , Receptores de Superficie Celular/metabolismo , Proteínas Recombinantes de Fusión , Espectrometría de Masas en Tándem
10.
Plant Cell ; 24(6): 2262-78, 2012 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-22693282

RESUMEN

Global climate change and a growing population require tackling the reduction in arable land and improving biomass production and seed yield per area under varying conditions. One of these conditions is suboptimal water availability. Here, we review some of the classical approaches to dealing with plant response to drought stress and we evaluate how research on RECEPTOR-LIKE KINASES (RLKs) can contribute to improving plant performance under drought stress. RLKs are considered as key regulators of plant architecture and growth behavior, but they also function in defense and stress responses. The available literature and analyses of available transcript profiling data indeed suggest that RLKs can play an important role in optimizing plant responses to drought stress. In addition, RLK pathways are ideal targets for nontransgenic approaches, such as synthetic molecules, providing a novel strategy to manipulate their activity and supporting translational studies from model species, such as Arabidopsis thaliana, to economically useful crops.


Asunto(s)
Sequías , Fenómenos Fisiológicos de las Plantas , Proteínas Quinasas/fisiología , Proyectos de Investigación , Arabidopsis/fisiología , Regulación de la Expresión Génica de las Plantas , Reguladores del Crecimiento de las Plantas/química , Reguladores del Crecimiento de las Plantas/metabolismo , Biosíntesis de Proteínas , Estrés Fisiológico
11.
Proc Natl Acad Sci U S A ; 109(1): 303-8, 2012 Jan 03.
Artículo en Inglés | MEDLINE | ID: mdl-22087006

RESUMEN

Plants and animals use innate immunity as a first defense against pathogens, a costly yet necessary tradeoff between growth and immunity. In Arabidopsis, the regulatory leucine-rich repeat receptor-like kinase (LRR-RLK) BAK1 combines with the LRR-RLKs FLS2 and EFR in pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) and the LRR-RLK BRI1 in brassinosteroid (BR)-mediated growth. Therefore, a potential tradeoff between these pathways mediated by BAK1 is often postulated. Here, we show a unidirectional inhibition of FLS2-mediated immune signaling by BR perception. Unexpectedly, this effect occurred downstream or independently of complex formation with BAK1 and associated downstream phosphorylation. Thus, BAK1 is not rate-limiting in these pathways. BRs also inhibited signaling triggered by the BAK1-independent recognition of the fungal PAMP chitin. Our results suggest a general mechanism operative in plants in which BR-mediated growth directly antagonizes innate immune signaling.


Asunto(s)
Arabidopsis/inmunología , Arabidopsis/microbiología , Brasinoesteroides/farmacología , Inmunidad de la Planta/efectos de los fármacos , Pseudomonas/metabolismo , Receptores de Reconocimiento de Patrones/metabolismo , Transducción de Señal/efectos de los fármacos , Arabidopsis/efectos de los fármacos , Arabidopsis/enzimología , Proteínas de Arabidopsis/metabolismo , Activación Enzimática/efectos de los fármacos , Flagelina/farmacología , Inmunidad de la Planta/inmunología , Proteínas Quinasas/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Pseudomonas/efectos de los fármacos , Transducción de Señal/inmunología , Esteroides Heterocíclicos/farmacología
12.
Plant Physiol ; 163(3): 1472-81, 2013 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-24072582

RESUMEN

Brassinosteroids (BRs) are key regulators in plant growth and development. The main BR-perceiving receptor in Arabidopsis (Arabidopsis thaliana) is BRASSINOSTEROID INSENSITIVE1 (BRI1). Seedling root growth and hypocotyl elongation can be accurately predicted using a model for BRI1 receptor activity. Genetic evidence shows that non-ligand-binding coreceptors of the SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASE (SERK) family are essential for BRI1 signal transduction. A relatively simple biochemical model based on the properties of SERK loss-of-function alleles explains complex physiological responses of the BRI1-mediated BR pathway. The model uses BRI1-BR occupancy as the central estimated parameter and includes BRI1-SERK interaction based on mass action kinetics and accurately describes wild-type root growth and hypocotyl elongation. Simulation studies suggest that the SERK coreceptors primarily act to increase the magnitude of the BRI1 signal. The model predicts that only a small number of active BRI1-SERK complexes are required to carry out BR signaling at physiological ligand concentration. Finally, when calibrated with single mutants, the model predicts that roots of the serk1serk3 double mutant are almost completely brassinolide (BL) insensitive, while the double mutant hypocotyls remain sensitive. This points to residual BRI1 signaling or to a different coreceptor requirement in shoots.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Modelos Teóricos , Proteínas Quinasas/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Transducción de Señal , Algoritmos , Arabidopsis/efectos de los fármacos , Arabidopsis/genética , Arabidopsis/crecimiento & desarrollo , Proteínas de Arabidopsis/genética , Brasinoesteroides/farmacología , Proteínas Fluorescentes Verdes/genética , Proteínas Fluorescentes Verdes/metabolismo , Hipocótilo/efectos de los fármacos , Hipocótilo/genética , Hipocótilo/crecimiento & desarrollo , Microscopía Confocal , Mutación , Raíces de Plantas/efectos de los fármacos , Raíces de Plantas/genética , Raíces de Plantas/crecimiento & desarrollo , Plantas Modificadas Genéticamente , Unión Proteica , Proteínas Quinasas/genética , Proteínas Serina-Treonina Quinasas/genética , Esteroides Heterocíclicos/farmacología
13.
Plant Physiol ; 162(4): 1911-25, 2013 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-23796795

RESUMEN

The leucine-rich repeat receptor-like kinase BRASSINOSTEROID-INSENSITIVE1 (BRI1) is the main ligand-perceiving receptor for brassinosteroids (BRs) in Arabidopsis (Arabidopsis thaliana). Binding of BRs to the ectodomain of plasma membrane (PM)-located BRI1 receptors initiates an intracellular signal transduction cascade that influences various aspects of plant growth and development. Even though the major components of BR signaling have been revealed and the PM was identified as the main site of BRI1 signaling activity, the very first steps of signal transmission are still elusive. Recently, it was shown that the initiation of BR signal transduction requires the interaction of BRI1 with its SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASE (SERK) coreceptors. In addition, the resolved structure of the BRI1 ectodomain suggested that BRI1-ASSOCIATED KINASE1 [BAK1](SERK3) may constitute a component of the ligand-perceiving receptor complex. Therefore, we investigated the spatial correlation between BRI1 and BAK1(SERK3) in the natural habitat of both leucine-rich repeat receptor-like kinases using comparative colocalization analysis and fluorescence lifetime imaging microscopy. We show that activation of BR signaling by exogenous ligand application resulted in both elevated colocalization between BRI1 and BAK1(SERK3) and an about 50% increase of receptor heterooligomerization in the PM of live Arabidopsis root epidermal cells. However, large populations of BRI1 and BAK1(SERK3) colocalized independently of BRs. Moreover, we could visualize that approximately 7% of the BRI1 PM pool constitutively heterooligomerizes with BAK1(SERK3) in live root cells. We propose that only small populations of PM-located BRI1 and BAK1(SERK3) receptors participate in active BR signaling and that the initiation of downstream signal transduction involves preassembled BRI1-BAK1(SERK3) heterooligomers.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Brasinoesteroides/metabolismo , Proteínas Quinasas/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Arabidopsis/efectos de los fármacos , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Brefeldino A/metabolismo , Brefeldino A/farmacología , Membrana Celular/metabolismo , Microscopía Fluorescente/métodos , Raíces de Plantas/citología , Raíces de Plantas/metabolismo , Plantas Modificadas Genéticamente , Proteínas Quinasas/genética , Multimerización de Proteína , Proteínas Serina-Treonina Quinasas/genética , Transducción de Señal , Triazoles/farmacología
14.
Plant Cell ; 23(6): 2440-55, 2011 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-21693696

RESUMEN

Recognition of pathogen-associated molecular patterns (PAMPs) by surface-localized pattern recognition receptors (PRRs) constitutes an important layer of innate immunity in plants. The leucine-rich repeat (LRR) receptor kinases EF-TU RECEPTOR (EFR) and FLAGELLIN SENSING2 (FLS2) are the PRRs for the peptide PAMPs elf18 and flg22, which are derived from bacterial EF-Tu and flagellin, respectively. Using coimmunoprecipitation and mass spectrometry analyses, we demonstrated that EFR and FLS2 undergo ligand-induced heteromerization in planta with several LRR receptor-like kinases that belong to the SOMATIC-EMBRYOGENESIS RECEPTOR-LIKE KINASE (SERK) family, including BRASSINOSTEROID INSENSITIVE1-ASSOCIATED KINASE1/SERK3 (BAK1/SERK3) and BAK1-LIKE1/SERK4 (BKK1/SERK4). Using a novel bak1 allele that does not exhibit pleiotropic defects in brassinosteroid and cell death responses, we determined that BAK1 and BKK1 cooperate genetically to achieve full signaling capability in response to elf18 and flg22 and to the damage-associated molecular pattern AtPep1. Furthermore, we demonstrated that BAK1 and BKK1 contribute to disease resistance against the hemibiotrophic bacterium Pseudomonas syringae and the obligate biotrophic oomycete Hyaloperonospora arabidopsidis. Our work reveals that the establishment of PAMP-triggered immunity (PTI) relies on the rapid ligand-induced recruitment of multiple SERKs within PRR complexes and provides insight into the early PTI signaling events underlying this important layer of plant innate immunity.


Asunto(s)
Proteínas de Arabidopsis/inmunología , Arabidopsis/enzimología , Arabidopsis/inmunología , Inmunidad Innata , Oomicetos/patogenicidad , Enfermedades de las Plantas/inmunología , Proteínas Quinasas/metabolismo , Proteínas Serina-Treonina Quinasas/inmunología , Secuencia de Aminoácidos , Arabidopsis/genética , Arabidopsis/microbiología , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Ligandos , Datos de Secuencia Molecular , Complejos Multienzimáticos/genética , Complejos Multienzimáticos/metabolismo , Oomicetos/inmunología , Péptidos/genética , Péptidos/metabolismo , Proteínas Quinasas/genética , Proteínas Serina-Treonina Quinasas/genética , Pseudomonas syringae/inmunología , Pseudomonas syringae/patogenicidad , Proteínas Recombinantes de Fusión/metabolismo , Transducción de Señal
15.
Plant Physiol ; 160(1): 523-32, 2012 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-22802611

RESUMEN

Brassinosteroid (BR) signaling is essential for plant growth and development. In Arabidopsis (Arabidopsis thaliana), BRs are perceived by the BRASSINOSTEROID INSENSITIVE1 (BRI1) receptor. Root growth and hypocotyl elongation are convenient downstream physiological outputs of BR signaling. A computational approach was employed to predict root growth solely on the basis of BRI1 receptor activity. The developed mathematical model predicts that during normal root growth, few receptors are occupied with ligand. The model faithfully predicts root growth, as observed in bri1 loss-of-function mutants. For roots, it incorporates one stimulatory and two inhibitory modules, while for hypocotyls, a single inhibitory module is sufficient. Root growth as observed when BRI1 is overexpressed can only be predicted assuming that a decrease occurred in the BRI1 half-maximum response values. Root growth appears highly sensitive to variation in BR concentration and much less to reduction in BRI1 receptor level, suggesting that regulation occurs primarily by ligand availability and biochemical activity.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/crecimiento & desarrollo , Hipocótilo/crecimiento & desarrollo , Modelos Teóricos , Raíces de Plantas/crecimiento & desarrollo , Proteínas Quinasas/metabolismo , Transducción de Señal , Arabidopsis/efectos de los fármacos , Arabidopsis/metabolismo , Brasinoesteroides/metabolismo , Brasinoesteroides/farmacología , Biología Computacional/métodos , Medios de Cultivo/metabolismo , Proteínas Fluorescentes Verdes/metabolismo , Hipocótilo/efectos de los fármacos , Hipocótilo/metabolismo , Ligandos , Raíces de Plantas/efectos de los fármacos , Raíces de Plantas/metabolismo , Receptores de Superficie Celular/metabolismo , Esteroides Heterocíclicos/metabolismo , Esteroides Heterocíclicos/farmacología , Triazoles/farmacología
16.
Plant Cell Environ ; 36(9): 1728-37, 2013 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-23421559

RESUMEN

Computational models are useful tools to help understand signalling pathways in plant cells. A systems biology approach where models and experimental data are combined can provide experimentally verifiable predictions and novel insights. The brassinosteroid insensitive 1 (BRI1) receptor is one of the best-understood receptor systems in Arabidopsis with clearly described ligands, mutants and associated phenotypes. Therefore, BRI1-mediated signalling is attractive for mathematical modelling approaches to understand and interpret the spatial and temporal dynamics of signal transduction cascades in planta. To establish such a model, quantitative data sets incorporating local protein concentration, binding affinity and phosphorylation state of the different pathway components are essential. Computational modelling is increasingly employed in studies of plant growth and development. In this section, we have focused on the use of quantitative imaging of fluorescently labelled proteins as an entry point in modelling studies.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Modelos Biológicos , Proteínas Quinasas/metabolismo , Brasinoesteroides/metabolismo , Receptor Cross-Talk , Transducción de Señal
17.
Plant Cell ; 22(4): 1344-57, 2010 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-20435907

RESUMEN

Plants constantly adjust their repertoire of plasma membrane proteins that mediates transduction of environmental and developmental signals as well as transport of ions, nutrients, and hormones. The importance of regulated secretory and endocytic trafficking is becoming increasingly clear; however, our knowledge of the compartments and molecular machinery involved is still fragmentary. We used immunogold electron microscopy and confocal laser scanning microscopy to trace the route of cargo molecules, including the BRASSINOSTEROID INSENSITIVE1 receptor and the REQUIRES HIGH BORON1 boron exporter, throughout the plant endomembrane system. Our results provide evidence that both endocytic and secretory cargo pass through the trans-Golgi network/early endosome (TGN/EE) and demonstrate that cargo in late endosomes/multivesicular bodies is destined for vacuolar degradation. Moreover, using spinning disc microscopy, we show that TGN/EEs move independently and are only transiently associated with an individual Golgi stack.


Asunto(s)
Arabidopsis/metabolismo , Cuerpos Multivesiculares/metabolismo , Red trans-Golgi/metabolismo , Antiportadores/metabolismo , Proteínas de Arabidopsis/metabolismo , Endocitosis , Microscopía Confocal , Microscopía Electrónica de Transmisión , Proteínas Quinasas/metabolismo , Transporte de Proteínas
18.
Dev Cell ; 13(2): 162-4, 2007 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-17681126

RESUMEN

Brassinosteroid (BR) signaling requires the BIN2 kinase-promoted interaction of 14-3-3 proteins with the transcriptional regulators BZR1 and BZR2, which are subsequently redistributed to the cytoplasm by BRs. In this issue of Developmental Cell, Gampala et al. show that this redistribution may fine-tune BR responses and serve to crosstalk with other signaling pathways.


Asunto(s)
Proteínas 14-3-3/metabolismo , Arabidopsis/metabolismo , Transducción de Señal , Esteroides Heterocíclicos/metabolismo , Proteínas 14-3-3/química , Arabidopsis/efectos de los fármacos , Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Proteínas de Unión al ADN , Dimerización , Humanos , Modelos Biológicos , Proteínas Nucleares/química , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Proteínas Quinasas/metabolismo , Esteroides Heterocíclicos/farmacología
19.
Plant Physiol ; 156(4): 1691-700, 2011 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-21617031

RESUMEN

In plants, green fluorescent protein (GFP) is routinely used to determine the subcellular location of fusion proteins. Here, we show that confocal imaging can be employed to approximate the number of GFP-labeled protein molecules present in living Arabidopsis (Arabidopsis thaliana) root cells. The technique involves calibration with soluble GFP to provide a usable protein concentration range within the confocal volume of the microscope. As a proof of principle, we quantified the Brassinosteroid Insensitive1 (BRI1) receptor fused to GFP, under control of its own promoter. The number of BRI1-GFP molecules per root epidermal cell ranges from 22,000 in the meristem and 130,000 in the elongation zone to 80,000 in the maturation zone, indicating that up to 6-fold differences in BRI1 receptor content exist. In contrast, when taking into account differences in cell size, BRI1-GFP receptor density in the plasma membrane is kept constant at 12 receptors µm⁻² in all cells throughout the meristem and elongation zone. Only the quiescent center and columella cells deviate from this pattern and have 5 to 6 receptors µm⁻². Remarkably, root cell sensitivity toward brassinosteroids appears to coincide with uniform meristem receptor density.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Proteínas Quinasas/metabolismo , Arabidopsis/citología , Western Blotting , Tamaño de la Célula , Proteínas Fluorescentes Verdes/metabolismo , Meristema/citología , Meristema/metabolismo , Microscopía Confocal , Especificidad de Órganos , Epidermis de la Planta/citología , Epidermis de la Planta/metabolismo , Proteínas Recombinantes de Fusión/metabolismo , Reproducibilidad de los Resultados , Plantones/metabolismo
20.
Nucleic Acids Res ; 38(9): 2839-50, 2010 May.
Artículo en Inglés | MEDLINE | ID: mdl-20110263

RESUMEN

The transcription factor peroxisome proliferator-activated receptor alpha (PPARalpha) is an important regulator of hepatic lipid metabolism. While PPARalpha is known to activate transcription of numerous genes, no comprehensive picture of PPARalpha binding to endogenous genes has yet been reported. To fill this gap, we performed Chromatin immunoprecipitation (ChIP)-chip in combination with transcriptional profiling on HepG2 human hepatoma cells treated with the PPARalpha agonist GW7647. We found that GW7647 increased PPARalpha binding to 4220 binding regions. GW7647-induced binding regions showed a bias around the transcription start site and most contained a predicted PPAR binding motif. Several genes known to be regulated by PPARalpha, such as ACOX1, SULT2A1, ACADL, CD36, IGFBP1 and G0S2, showed GW7647-induced PPARalpha binding to their promoter. A GW7647-induced PPARalpha-binding region was also assigned to SREBP-targets HMGCS1, HMGCR, FDFT1, SC4MOL, and LPIN1, expression of which was induced by GW7647, suggesting cross-talk between PPARalpha and SREBP signaling. Our data furthermore demonstrate interaction between PPARalpha and STAT transcription factors in PPARalpha-mediated transcriptional repression, and suggest interaction between PPARalpha and TBP, and PPARalpha and C/EBPalpha in PPARalpha-mediated transcriptional activation. Overall, our analysis leads to important new insights into the mechanisms and impact of transcriptional regulation by PPARalpha in human liver and highlight the importance of cross-talk with other transcription factors.


Asunto(s)
Regulación de la Expresión Génica , PPAR alfa/metabolismo , Regiones Promotoras Genéticas , Sitios de Unión , Carcinoma Hepatocelular , Línea Celular Tumoral , Inmunoprecipitación de Cromatina , Análisis por Conglomerados , Perfilación de la Expresión Génica , Humanos , Neoplasias Hepáticas , Análisis de Secuencia por Matrices de Oligonucleótidos , Sitio de Iniciación de la Transcripción
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA