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1.
PLoS Pathog ; 20(5): e1012210, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38709737

RESUMEN

[This corrects the article DOI: 10.1371/journal.ppat.1008437.].

2.
Materials (Basel) ; 17(5)2024 Mar 04.
Artículo en Inglés | MEDLINE | ID: mdl-38473658

RESUMEN

Process parameters and powder spreading quality are important factors for aluminum matrix composites (AMCs) prepared using laser powder bed fusion (LPBF). In this study, a Box-Behnken Design (BBD) was used to optimize the process parameters, and near-spherical ß-SiC was selected to improve the quality of powder spreading. The rationality of parameter optimization was verified by testing the density of samples prepared using different laser power levels. Al4C3 diffraction peaks were found in XRD patterns, which indicated that interface reactions occurred to form good interface bonding between the Al matrix and the SiC particles. The tensile strength and plasticity of LPBF α-SiC/AlSi10Mg were lower than that of LPBF AlSi10Mg, which was mainly due to the poor fluidity of the powder mixtures and powder spreading quality. For LPBF ß-SiC/AlSi10Mg, the tensile strength increased and elongation decreased slightly compared to LPBF α-SiC/AlSi10Mg. The data in this study were compared with the data in other studies. In this study, LPBF AlSi10Mg and LPBF ß-SiC/AlSi10Mg not only showed the inherent high strength of their LPBF parts, but also had relatively high plasticity. Matching between strength and plasticity was mainly dependent on the scanning strategy. Most studies use uni-directional or bi-directional scanning strategies with a certain rotation angle between layers. A chessboard scanning strategy was used in this study to form a coarse remelted connected skeleton inside the material and significantly improve plasticity. This study lays a theoretical and experimental foundation for the controllable preparation of SiC-reinforced AMCs using LPBF.

3.
Int J Mol Sci ; 25(5)2024 Feb 26.
Artículo en Inglés | MEDLINE | ID: mdl-38473921

RESUMEN

Cytoskeletal microtubules (MTs) play crucial roles in many aspects of life processes in eukaryotic organisms. They dynamically assemble physiologically important MT arrays under different cell conditions. Currently, aspects of MT assembly underlying the development and pathogenesis of the model plant pathogenic fungus Magnaporthe oryzae (M. oryzae) are unclear. In this study, we characterized the MT plus end binding protein MoMal3 in M. oryzae. We found that knockout of MoMal3 results in defects in hyphal polar growth, appressorium-mediated host penetration and nucleus division. Using high-resolution live-cell imaging, we further found that the MoMal3 mutant assembled a rigid MT in parallel with the MT during hyphal polar growth, the cage-like network in the appressorium and the stick-like spindle in nuclear division. These aberrant MT organization patterns in the MoMal3 mutant impaired actin-based cell growth and host infection. Taken together, these findings showed that M. oryzae relies on MoMal3 to assemble elaborate MT arrays for growth and infection. The results also revealed the assembly mode of MTs in M. oryzae, indicating that MTs are pivotal for M. oryzae growth and host infection and may be new targets for devastating fungus control.


Asunto(s)
Ascomicetos , Magnaporthe , Oryza , Proteínas Portadoras/metabolismo , Magnaporthe/fisiología , Ascomicetos/metabolismo , Microtúbulos/metabolismo , Oryza/metabolismo , Enfermedades de las Plantas/microbiología , Proteínas Fúngicas/metabolismo
4.
Stress Biol ; 4(1): 5, 2024 Jan 22.
Artículo en Inglés | MEDLINE | ID: mdl-38252344

RESUMEN

The dynamic assembly of the actin cytoskeleton is vital for Magnaporthe oryzae development and host infection. The actin-related protein MoFim1 is a key factor for organizing the M. oryzae actin cytoskeleton. Currently, how MoFim1 is regulated in M. oryzae to precisely rearrange the actin cytoskeleton is unclear. In this study, we found that MoFim1 associates with the M. oryzae mitogen-activated protein (MAP) kinase Pmk1 to regulate actin assembly. MoFim1 directly interacted with Pmk1, and the phosphorylation level of MoFim1 was decreased in Δpmk1, which led to a change in the subcellular distribution of MoFim1 in the hyphae of Δpmk1. Moreover, the actin cytoskeleton was aberrantly organized at the hyphal tip in the Δpmk1, which was similar to what was observed in the Δmofim1 during hyphal growth. Furthermore, phosphorylation analysis revealed that Pmk1 could phosphorylate MoFim1 at serine 94. Loss of phosphorylation of MoFim1 at serine 94 decreased actin bundling activity. Additionally, the expression of the site mutant of MoFim1 S94D (in which serine 94 was replaced with aspartate to mimic phosphorylation) in Δpmk1 could reverse the defects in actin organization and hyphal growth in Δpmk1. It also partially rescues the formation of appressorium failure in Δpmk1. Taken together, these findings suggest a regulatory mechanism in which Pmk1 phosphorylates MoFim1 to regulate the assembly of the actin cytoskeleton during hyphal development and pathogenesis.

5.
BMC Cancer ; 22(1): 752, 2022 Jul 11.
Artículo en Inglés | MEDLINE | ID: mdl-35820889

RESUMEN

BACKGROUND: Tyrosine kinase inhibitors (TKIs) are mainstays of cancer treatment. However, their clinical benefits are often constrained by acquired resistance. To overcome such outcomes, we have rationally engineered APG-2449 as a novel multikinase inhibitor that is highly potent against oncogenic alterations of anaplastic lymphoma kinase (ALK), ROS proto-oncogene 1 receptor tyrosine kinase (ROS1), and focal adhesion kinase (FAK). Here we present the preclinical evaluation of APG-2449, which exhibits antiproliferative activity in cells carrying ALK fusion or secondary mutations. METHODS: KINOMEscan® and LANCE TR-FRET were used to characterize targets and selectivity of APG-2449. Water-soluble tetrazolium salt (WST-8) viability assay and xenograft tumorigenicity were employed to evaluate therapeutic efficacy of monotherapy or drug combination in preclinical models of solid tumors. Western blot, pharmacokinetic, and flow cytometry analyses, as well as RNA sequencing were used to explore pharmacokinetic-pharmacodynamic correlations and the mechanism of actions driving drug combination synergy. RESULTS: In mice bearing wild-type or ALK/ROS1-mutant non-small-cell lung cancer (NSCLC), APG-2449 demonstrates potent antitumor activity, with correlations between pharmacokinetics and pharmacodynamics in vivo. Through FAK inhibition, APG-2449 sensitizes ovarian xenograft tumors to paclitaxel by reducing CD44+ and aldehyde dehydrogenase 1-positive (ALDH1+) cancer stem cell populations, including ovarian tumors insensitive to carboplatin. In epidermal growth factor receptor (EGFR)-mutated NSCLC xenograft models, APG-2449 enhances EGFR TKI-induced tumor growth inhibition, while the ternary combination of APG-2449 with EGFR (osimertinib) and mitogen-activated extracellular signal-regulated kinase (MEK; trametinib) inhibitors overcomes osimertinib resistance. Mechanistically, phosphorylation of ALK, ROS1, and FAK, as well as their downstream components, is effectively inhibited by APG-2449. CONCLUSIONS: Taken together, our studies demonstrate that APG-2449 exerts potent and durable antitumor activity in human NSCLC and ovarian tumor models when administered alone or in combination with other therapies. A phase 1 clinical trial has been initiated to evaluate the safety and preliminary efficacy of APG-2449 in patients with advanced solid tumors, including ALK+ NSCLC refractory to earlier-generation ALK inhibitors. TRIAL REGISTRATION: Clinicaltrial.gov registration: NCT03917043 (date of first registration, 16/04/2019) and Chinese clinical trial registration: CTR20190468 (date of first registration, 09/04/2019).


Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas , Neoplasias Pulmonares , Neoplasias Ováricas , Animales , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Carcinoma de Pulmón de Células no Pequeñas/genética , Carcinoma de Pulmón de Células no Pequeñas/metabolismo , Carcinoma Epitelial de Ovario/tratamiento farmacológico , Ensayos Clínicos Fase I como Asunto , Receptores ErbB/genética , Receptores ErbB/uso terapéutico , Femenino , Proteína-Tirosina Quinasas de Adhesión Focal , Humanos , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patología , Ratones , Neoplasias Ováricas/tratamiento farmacológico , Neoplasias Ováricas/genética , Inhibidores de Proteínas Quinasas/farmacología , Inhibidores de Proteínas Quinasas/uso terapéutico , Proteínas Tirosina Quinasas , Proteínas Proto-Oncogénicas/genética , Proteínas Tirosina Quinasas Receptoras/metabolismo
6.
Plants (Basel) ; 11(14)2022 Jul 12.
Artículo en Inglés | MEDLINE | ID: mdl-35890462

RESUMEN

LIM proteins are widely spread in various types of plant cells and play diversely crucial cellular roles through actin cytoskeleton assembly and gene expression regulation. Till now, it has not been clear whether LIM proteins function in plant pathogen defense. In this study, we characterized a LIM protein, GhWLIM1C, in upland cotton (Gossypium hirsutum). We found that GhWLIM1C could bind and bundle the actin cytoskeleton, and it contains two LIM domains (LIM1 and LIM2). Both the two domains could bind directly to the actin filaments. Moreover, the LIM2 domain additionally bundles the actin cytoskeleton, indicating that it possesses a different biochemical activity than LIM1. The expression of GhWLIM1C responds to the infection of the cotton fungal pathogen Verticillium dahliae (V. dahliae). Silencing of GhWLIM1C decreased cotton resistance to V. dahliae. These may be associated with the down regulated plant defense response, including the PR genes expression and ROS accumulation in the infected cotton plants. In all, these results provide new evidence that a plant LIM protein functions in plant pathogen resistance and the assembly of the actin cytoskeleton are closely related to the triggering of the plant defense response.

7.
Mol Plant Pathol ; 22(12): 1656-1667, 2021 12.
Artículo en Inglés | MEDLINE | ID: mdl-34515397

RESUMEN

Several studies have revealed that actin depolymerizing factors (ADFs) participate in plant defence responses; however, the functional mechanisms appear intricate and need further exploration. In this study, we identified an ADF6 gene in upland cotton (designated as GhADF6) that is evidently involved in cotton's response to the fungal pathogen Verticillium dahliae. GhADF6 binds to actin filaments and possesses actin severing and depolymerizing activities in vitro and in vivo. When cotton root (the site of the fungus invasion) was inoculated with the pathogen, the expression of GhADF6 was markedly down-regulated in the epidermal cells. By virus-induced gene silencing analysis, the down-regulation of GhADF6 expression rendered the cotton plants tolerant to V. dahliae infection. Accordingly, the abundance of actin filaments and bundles in the root cells was significantly higher than that in the control plant, which phenocopied that of the V. dahliae-challenged wild-type cotton plant. Altogether, our results provide evidence that an increase in filament actin (F-actin) abundance as well as dynamic actin remodelling are required for plant defence against the invading pathogen, which are likely to be fulfilled by the coordinated expressional regulation of the actin-binding proteins, including ADF.


Asunto(s)
Factores Despolimerizantes de la Actina/genética , Resistencia a la Enfermedad , Gossypium , Enfermedades de las Plantas/microbiología , Verticillium , Actinas , Ascomicetos , Resistencia a la Enfermedad/genética , Regulación de la Expresión Génica de las Plantas , Gossypium/genética , Gossypium/microbiología , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Verticillium/patogenicidad
8.
Mol Plant Pathol ; 22(12): 1641-1655, 2021 12.
Artículo en Inglés | MEDLINE | ID: mdl-34519407

RESUMEN

Actin assembly at the hyphal tip is key for polar growth and pathogenesis of the rice blast fungus Magnaporthe oryzae. The mechanism of its precise assemblies and biological functions is not understood. Here, we characterized the role of M. oryzae Twinfilin (MoTwf) in M. oryzae infection through organizing the actin cables that connect to Spitzenkörper (Spk) at the hyphal tip. MoTwf could bind and bundle the actin filaments. It formed a complex with Myosin2 (MoMyo2) and the Woronin body protein Hexagonal peroxisome 1 (MoHex1). Enrichment of MoMyo2 and MoHex1 in the hyphal apical region was disrupted in a ΔMotwf loss-of-function mutant, which also showed a decrease in the number and width of actin cables. These findings indicate that MoTwf participates in the virulence of M. oryzae by organizing Spk-connected actin filaments and regulating MoHex1 distribution at the hyphal tip.


Asunto(s)
Magnaporthe , Oryza , Actinas/genética , Ascomicetos , Proteínas Fúngicas/genética , Magnaporthe/genética , Peroxisomas , Enfermedades de las Plantas
9.
PLoS Pathog ; 16(3): e1008437, 2020 03.
Artículo en Inglés | MEDLINE | ID: mdl-32176741

RESUMEN

Magnaporthe oryzae causes rice blast disease, but little is known about the dynamic restructuring of the actin cytoskeleton during its polarized tip growth and pathogenesis. Here, we used super-resolution live-cell imaging to investigate the dynamic organization of the actin cytoskeleton in M. oryzae during hyphal tip growth and pathogenesis. We observed a dense actin network at the apical region of the hyphae and actin filaments originating from the Spitzenkörper (Spk, the organizing center for hyphal growth and development) that formed branched actin bundles radiating to the cell membrane. The actin cross-linking protein Fimbrin (MoFim1) helps organize this actin distribution. MoFim1 localizes to the actin at the subapical collar, the actin bundles, and actin at the Spk. Knockout of MoFim1 resulted in impaired Spk maintenance and reduced actin bundle formation, preventing polar growth, vesicle transport, and the expansion of hyphae in plant cells. Finally, transgenic rice (Oryza sativa) expressing RNA hairpins targeting MoFim1 exhibited improved resistance to M. oryzae infection, indicating that MoFim1 represents an excellent candidate for M. oryzae control. These results reveal the dynamics of actin assembly in M. oryzae during hyphal tip development and pathogenesis, and they suggest a mechanism in which MoFim1 organizes such actin networks.


Asunto(s)
Actinas , Proteínas Fúngicas , Hifa , Magnaporthe , Glicoproteínas de Membrana , Proteínas de Microfilamentos , Oryza/microbiología , Enfermedades de las Plantas/microbiología , Actinas/genética , Actinas/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Hifa/genética , Hifa/crecimiento & desarrollo , Magnaporthe/genética , Magnaporthe/metabolismo , Magnaporthe/patogenicidad , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/metabolismo , Proteínas de Microfilamentos/genética , Proteínas de Microfilamentos/metabolismo
10.
Plant Cell ; 31(2): 520-536, 2019 02.
Artículo en Inglés | MEDLINE | ID: mdl-30651348

RESUMEN

The apoplast serves as the first battlefield between the plant hosts and invading microbes; therefore, work on plant-pathogen interactions has increasingly focused on apoplastic immunity. In this study, we identified three proteins in the apoplast of cotton (Gossypium sp) root cells during interaction of the plant with the fungal pathogen Verticillium dahliae Among these proteins, cotton host cells secrete chitinase 28 (Chi28) and the Cys-rich repeat protein 1 (CRR1), while the pathogen releases the protease VdSSEP1. Biochemical analysis demonstrated that VdSSEP1 hydrolyzed Chi28, but CRR1 protected Chi28 from cleavage by Verticillium dahliae secretory Ser protease 1 (VdSSEP1). In accordance with the in vitro results, CRR1 interacted with Chi28 in yeast and plant cells and attenuated the observed decrease in Chi28 level that occurred in the apoplast of plant cells upon pathogen attack. Knockdown of CRR1 or Chi28 in cotton plants resulted in higher susceptibility to V. dahliae infection, and overexpression of CRR1 increased plant resistance to V dahliae, the fungus Botrytis cinerea, and the oomycete Phytophthora parasitica var nicotianae By contrast, knockout of VdSSEP1 in V. dahliae destroyed the pathogenicity of this fungus. Together, our results provide compelling evidence for a multilayered interplay of factors in cotton apoplastic immunity.


Asunto(s)
Quitinasas/metabolismo , Gossypium/metabolismo , Gossypium/microbiología , Proteínas de Plantas/metabolismo , Verticillium/patogenicidad , Quitinasas/genética , Resistencia a la Enfermedad/genética , Regulación de la Expresión Génica de las Plantas/genética , Regulación de la Expresión Génica de las Plantas/fisiología , Gossypium/genética , Enfermedades de las Plantas/genética , Enfermedades de las Plantas/microbiología , Proteínas de Plantas/genética
11.
Cell Physiol Biochem ; 49(3): 947-960, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30184537

RESUMEN

BACKGROUND/AIMS: The hydroxylation of fatty acids at the C-2 position is the first step of fatty acid α-oxidation and generates sphingolipids containing 2-hydroxy fatty acyl moieties. Fatty acid 2-hydroxylation is catalyzed by Fatty acid 2-hydroxylase (FA2H) enzyme. However, the precise roles of FA2H and fatty acid 2-hydroxylation in whole cell homeostasis still remain unclear. METHODS: Here we utilize Caenorhabditis elegans as the model and systemically investigate the physiological functions of FATH-1/C25A1.5, the highly conserved worm homolog for mammalian FA2H enzyme. Immunostaining, dye-staining and translational fusion reporters were used to visualize FATH-1 protein and a variety of subcellular structures. The "click chemistry" method was employed to label 2-OH fatty acid in vivo. Global and tissue-specific RNAi knockdown experiments were performed to inactivate FATH-1 function. Lipid analysis of the fath-1 deficient mutants was achieved by mass spectrometry. RESULTS: C. elegans FATH-1 is expressed at most developmental stages and in most tissues. Loss of fath-1 expression results in severe growth retardation and shortened lifespan. FATH-1 function is crucially required in the intestine but not the epidermis with stereospecificity. The "click chemistry" labeling technique showed that the FATH-1 metabolites are mainly enriched in membrane structures preferable to the apical side of the intestinal cells. At the subcellular level, we found that loss of fath-1 expression inhibits lipid droplets formation, as well as selectively disrupts peroxisomes and apical endosomes. Lipid analysis of the fath-1 deficient animals revealed a significant reduction in the content of heptadecenoic acid, while other major FAs remain unaffected. Feeding of exogenous heptadecenoic acid (C17: 1), but not oleic acid (C18: 1), rescues the global and subcellular defects of fath-1 knockdown worms. CONCLUSION: Our study revealed that FATH-1 and its catalytic products are highly specific in the context of chirality, C-chain length, spatial distribution, as well as the types of cellular organelles they affect. Such an unexpected degree of specificity for the synthesis and functions of hydroxylated FAs helps to regulate protein transport and fat metabolism, therefore maintaining the cellular homeostasis of the intestinal cells. These findings may help our understanding of FA2H functions across species, and offer potential therapeutical targets for treating FA2H-related diseases.


Asunto(s)
Proteínas de Caenorhabditis elegans/metabolismo , Ácidos Grasos Monoinsaturados/metabolismo , Mucosa Intestinal/metabolismo , Oxigenasas de Función Mixta/metabolismo , Animales , Caenorhabditis elegans/crecimiento & desarrollo , Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/antagonistas & inhibidores , Proteínas de Caenorhabditis elegans/genética , Endosomas/metabolismo , Ácidos Grasos/análisis , Ácidos Grasos/metabolismo , Larva/metabolismo , Longevidad , Espectrometría de Masas , Oxigenasas de Función Mixta/antagonistas & inhibidores , Oxigenasas de Función Mixta/genética , Peroxisomas/metabolismo , Interferencia de ARN , ARN Interferente Pequeño/metabolismo , Estereoisomerismo
12.
J Cell Sci ; 131(11)2018 06 11.
Artículo en Inglés | MEDLINE | ID: mdl-29748380

RESUMEN

Hemidesmosomes are epithelial-specific attachment structures that maintain tissue integrity and resist tension. Despite their importance, how hemidesmosomes are regulated at the post-transcriptional level is poorly understood. Caenorhabditiselegans hemidesmosomes (CeHDs) have a similar structure and composition to their mammalian counterparts, making C. elegans an ideal model for studying hemidesmosomes. Here, we focus on the transcription regulator CCAR-1, identified in a previous genetic screen searching for enhancers of mutations in the conserved hemidesmosome component VAB-10A (known as plectin in mammals). Loss of CCAR-1 function in a vab-10(e698) background results in CeHD disruption and muscle detachment from the epidermis. CCAR-1 regulates CeHD biogenesis, not by controlling the transcription of CeHD-related genes, but by affecting the alternative splicing of unc-52 (known as perlecan or HSPG2 in mammals), the predicted basement extracellular matrix (ECM) ligand of CeHDs. CCAR-1 physically interacts with HRP-2 (hnRNPR in mammals), a splicing factor known to mediate unc-52 alternative splicing to control the proportions of different UNC-52 isoforms and stabilize CeHDs. Our discovery underlines the importance of post-transcriptional regulation in hemidesmosome reorganization. It also uncovers previously unappreciated roles of CCAR-1 in alternative splicing and hemidesmosome biogenesis, shedding new light on the mechanisms through which mammalian CCAR1 functions in tumorigenesis.


Asunto(s)
Empalme Alternativo , Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/metabolismo , Hemidesmosomas/metabolismo , Proteínas de la Membrana/metabolismo , Proteoglicanos/metabolismo , Animales , Caenorhabditis elegans/embriología , Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/genética , Epidermis/embriología , Epidermis/metabolismo , Hemidesmosomas/genética , Ribonucleoproteína Heterogénea-Nuclear Grupo A-B/genética , Ribonucleoproteína Heterogénea-Nuclear Grupo A-B/metabolismo , Proteínas de la Membrana/genética , Músculos/embriología , Músculos/metabolismo , Unión Proteica , Proteoglicanos/genética
13.
Plant Physiol ; 170(4): 2392-406, 2016 04.
Artículo en Inglés | MEDLINE | ID: mdl-26869704

RESUMEN

Examining the proteins that plants secrete into the apoplast in response to pathogen attack provides crucial information for understanding the molecular mechanisms underlying plant innate immunity. In this study, we analyzed the changes in the root apoplast secretome of the Verticillium wilt-resistant island cotton cv Hai 7124 (Gossypium barbadense) upon infection with Verticillium dahliae Two-dimensional differential gel electrophoresis and matrix-assisted laser desorption/ionization tandem time-of-flight mass spectrometry analysis identified 68 significantly altered spots, corresponding to 49 different proteins. Gene ontology annotation indicated that most of these proteins function in reactive oxygen species (ROS) metabolism and defense response. Of the ROS-related proteins identified, we further characterized a thioredoxin, GbNRX1, which increased in abundance in response to V. dahliae challenge, finding that GbNRX1 functions in apoplastic ROS scavenging after the ROS burst that occurs upon recognition of V. dahliae Silencing of GbNRX1 resulted in defective dissipation of apoplastic ROS, which led to higher ROS accumulation in protoplasts. As a result, the GbNRX1-silenced plants showed reduced wilt resistance, indicating that the initial defense response in the root apoplast requires the antioxidant activity of GbNRX1. Together, our results demonstrate that apoplastic ROS generation and scavenging occur in tandem in response to pathogen attack; also, the rapid balancing of redox to maintain homeostasis after the ROS burst, which involves GbNRX1, is critical for the apoplastic immune response.


Asunto(s)
Gossypium/metabolismo , Gossypium/microbiología , Homeostasis , Enfermedades de las Plantas/microbiología , Proteínas de Plantas/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Tiorredoxinas/metabolismo , Verticillium/fisiología , Resistencia a la Enfermedad , Perfilación de la Expresión Génica , Regulación de la Expresión Génica de las Plantas , Silenciador del Gen , Especificidad de Órganos/genética , Filogenia , Raíces de Plantas/metabolismo , Haz Vascular de Plantas/metabolismo , Proteómica
14.
Sci China Life Sci ; 59(2): 206-12, 2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-26803305

RESUMEN

Our previous study demonstrated that WLIM1a has dual roles in fiber elongation and secondary cell wall synthesis in upland cotton, and the protein acts either as an actin-binding protein or as a transcription factor. Because WLIM1a consists of two different LIM domains, it is possible that these elements contribute differentially to the dual functions of the protein. In this study, we dissected the two LIM domains and characterized their biochemical functions. By using red fluorescent protein (RFP) fusion, co-sedimentation, and DNA binding methods, we found that the two domains of WLIM1a, domain1 (D1) and domain2 (D2), possessed different biochemical properties. While D1 contributed primarily to the actin filament-bundling activity of WLIM1a, D2 contributed to the DNA-binding activity of the protein; both D1 and D2 relied on a linker sequence for their activities. In addition, we found that WLIM1a and its two LIM domains form dimers in vitro. These results may lead to a better understanding of the molecular mechanisms of dual functions of WLIM1a during cotton fiber development.


Asunto(s)
Gossypium/metabolismo , Proteínas de Plantas/metabolismo , Secuencia de Aminoácidos , Fibra de Algodón , Dimerización , Datos de Secuencia Molecular , Proteínas de Plantas/química , Homología de Secuencia de Aminoácido
15.
Immunity ; 42(2): 309-320, 2015 Feb 17.
Artículo en Inglés | MEDLINE | ID: mdl-25692704

RESUMEN

The epidermis constantly encounters invasions that disrupt its architecture, yet whether the epidermal immune system utilizes damaged structures as danger signals to activate self-defense is unclear. Here, we used a C. elegans epidermis model in which skin-penetrating infection or injury activates immune defense and antimicrobial peptide (AMP) production. By systemically disrupting each architectural component, we found that only disturbance of the apical hemidesmosomes triggered an immune response and robust AMP expression. The epidermis recognized structural damage through hemidesmosomes associated with a STAT-like protein, whose disruption led to detachment of STA-2 molecules from hemidesmosomes and transcription of AMPs. This machinery enabled the epidermis to bypass certain signaling amplification and directly trigger AMP production when subjected to extensive architectural damage. Together, our findings uncover an evolutionarily conserved mechanism for the epithelial barriers to detect danger and activate immune defense.


Asunto(s)
Péptidos Catiónicos Antimicrobianos/biosíntesis , Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/inmunología , Epidermis/inmunología , Epidermis/lesiones , Factores de Transcripción STAT/metabolismo , Animales , Péptidos Catiónicos Antimicrobianos/genética , Proteínas de Caenorhabditis elegans/inmunología , Moléculas de Adhesión Celular/inmunología , Células Cultivadas , Hemidesmosomas/inmunología , Hemidesmosomas/patología , Humanos , Inmunidad Innata , Queratinocitos/inmunología , Queratinocitos/metabolismo , Transducción de Señal/inmunología , Proteínas Quinasas p38 Activadas por Mitógenos/inmunología
16.
Plant Cell ; 25(11): 4421-38, 2013 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-24220634

RESUMEN

LIN-11, Isl1 and MEC-3 (LIM)-domain proteins play pivotal roles in a variety of cellular processes in animals, but plant LIM functions remain largely unexplored. Here, we demonstrate dual roles of the WLIM1a gene in fiber development in upland cotton (Gossypium hirsutum). WLIM1a is preferentially expressed during the elongation and secondary wall synthesis stages in developing fibers. Overexpression of WLIM1a in cotton led to significant changes in fiber length and secondary wall structure. Compared with the wild type, fibers of WLIM1a-overexpressing plants grew longer and formed a thinner and more compact secondary cell wall, which contributed to improved fiber strength and fineness. Functional studies demonstrated that (1) WLIM1a acts as an actin bundler to facilitate elongation of fiber cells and (2) WLIM1a also functions as a transcription factor to activate expression of Phe ammonia lyase-box genes involved in phenylpropanoid biosynthesis to build up the secondary cell wall. WLIM1a localizes in the cytosol and nucleus and moves into the nucleus in response to hydrogen peroxide. Taken together, these results demonstrate that WLIM1a has dual roles in cotton fiber development, elongation, and secondary wall formation. Moreover, our study shows that lignin/lignin-like phenolics may substantially affect cotton fiber quality; this finding may guide cotton breeding for improved fiber traits.


Asunto(s)
Pared Celular/metabolismo , Fibra de Algodón , Gossypium/citología , Gossypium/crecimiento & desarrollo , Proteínas de Plantas/metabolismo , Actinas/metabolismo , Núcleo Celular/metabolismo , Pared Celular/genética , Pared Celular/ultraestructura , Clonación Molecular , Citoplasma/metabolismo , Regulación de la Expresión Génica de las Plantas , Gossypium/efectos de los fármacos , Gossypium/genética , Peróxido de Hidrógeno/farmacología , Lignina/metabolismo , Filogenia , Células Vegetales/metabolismo , Proteínas de Plantas/genética , Plantas Modificadas Genéticamente , Transporte de Proteínas/efectos de los fármacos
17.
PLoS One ; 8(1): e54002, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23335985

RESUMEN

In plants, CuZn superoxide dismutase (CuZnSOD, EC l.15.1.1), ascorbate peroxidase (APX, EC 1.11.1.11), and catalase (CAT, EC l.11.1.6) are important scavengers of reactive oxygen species (ROS) to protect the cell from damage. In the present study, we isolated three homologous genes (GhSOD1, GhAPX1, and GhCAT1) from Gossypium hirsutum. Overexpressing cassettes containing chimeric GhSOD1, GhAPX1, or GhCAT1 were introduced into cotton plants by Agrobacterium transformation, and overexpressed products of these genes were transported into the chloroplasts by transit peptide, as expected. The five types of transgenic cotton plants that overexpressed GhSOD1, GhAPX1, GhCAT1, GhSOD1 and GhAPX1 stack (SAT), and GhSOD1 and GhCAT1 stack (SCT) were developed. Analyses in the greenhouse showed that the transgenic plants had higher tolerance to methyl viologen (MV) and salinity than WT plants. Interestingly, SCT plants suffered no damage under stress conditions. Based on analyses of enzyme activities, electrolyte leakage, chlorophyll content, photochemical yield (Fv/Fm), and biomass accumulation under stresses, the SCT plants that simultaneously overexpressed GhSOD1 and GhCAT1 appeared to benefit from synergistic effects of two genes and exhibited the highest tolerance to MV and salt stress among the transgenic lines, while the SAT plants simultaneously overexpressing GhSOD1 and GhAPX1 did not. In addition, transgenic plants overexpressing antioxidant enzymes in their chloroplasts had higher tolerance to salt stress than those expressing the genes in their cytoplasms, although overall enzyme activities were almost the same. Therefore, the synergistic effects of GhSOD1 and GhCAT1 in chloroplasts provide a new strategy for enhancing stress tolerance to avoid yield loss.


Asunto(s)
Adaptación Biológica/genética , Catalasa/genética , Cloroplastos/genética , Regulación de la Expresión Génica de las Plantas , Gossypium/genética , Estrés Fisiológico , Superóxido Dismutasa/genética , Ascorbato Peroxidasas/genética , Ascorbato Peroxidasas/metabolismo , Catalasa/metabolismo , Cloroplastos/metabolismo , Activación Enzimática/genética , Orden Génico , Gossypium/metabolismo , Estrés Oxidativo , Fenotipo , Plantas Modificadas Genéticamente , Tolerancia a la Sal/genética , Superóxido Dismutasa/metabolismo , Superóxido Dismutasa-1
18.
Plant Physiol Biochem ; 49(11): 1264-71, 2011 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-22000049

RESUMEN

The full-length cDNA of a cyclophilin-like gene was cloned from Gossypium hirsutum using rapid amplification of cDNA ends and was designated as GhCyp1, a member of the immunophilin protein family. GhCyp1 expression level was higher in roots and stems than in other tissues of cotton, as determined by real-time reverse transcription polymerase chain reaction (RT-PCR). To characterize the GhCyp1 gene, tobacco (Nicotiana tabacum) was transformed via Agrobacterium tumefaciens with a vector to express the gene under the control of a strong constitutive promoter, CaMV35S (Cauliflower Mosaic Virus). Based on analyses of tolerance to salinity stress and Pseudomonas syringae pv. tabaci (Pst) infection, the overexpression of GhCyp1 in transgenic plants conferred higher tolerance to salt stress and Pst infection compared with control plants. Therefore, we suggest that GhCyp1 may be a suitable candidate gene to produce transgenic plants with tolerance to abiotic and biotic stresses.


Asunto(s)
Ciclofilinas/genética , Gossypium/genética , Nicotiana/fisiología , Inmunidad de la Planta/fisiología , Pseudomonas syringae/fisiología , Secuencia de Aminoácidos , Ciclofilinas/química , Ciclofilinas/metabolismo , ADN Complementario/genética , Etiquetas de Secuencia Expresada , Regulación de la Expresión Génica de las Plantas , Datos de Secuencia Molecular , Filogenia , Enfermedades de las Plantas/inmunología , Enfermedades de las Plantas/microbiología , Hojas de la Planta/genética , Hojas de la Planta/microbiología , Hojas de la Planta/fisiología , Proteínas de Plantas/química , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raíces de Plantas/genética , Raíces de Plantas/microbiología , Raíces de Plantas/fisiología , Tallos de la Planta/genética , Tallos de la Planta/microbiología , Tallos de la Planta/fisiología , Plantas Modificadas Genéticamente , ARN de Planta/genética , Tolerancia a la Sal , Plantones/genética , Plantones/microbiología , Plantones/fisiología , Alineación de Secuencia , Cloruro de Sodio/metabolismo , Nicotiana/genética , Nicotiana/microbiología
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