Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 14.127
Filtrar
1.
Int J Mol Sci ; 25(19)2024 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-39409172

RESUMO

The plant vacuole is a very dynamic organelle that can occupy more than 90% of the cell volume and is essential to plant cell growth and development, the processes in which auxin (indole-3-acetic acid, IAA) is a central player. It was found that when IAA or FC (fusicoccin) was present in the control medium of vacuoles isolated from red beet taproots at a final concentration of 1 µM, it increased their volume to a level that was 26% or 36% higher than that observed in the control medium without growth regulators, respectively. In the presence of IAA and FC, the time after which most vacuoles ruptured was about 10 min longer for IAA than for FC. However, when cadmium (Cd) or lead (Pb) was present in the control medium at a final concentration of 100 µM, it increased the volume of the vacuoles by about 26% or 80% compared to the control, respectively. The time after which the vacuoles ruptured was similar for both metals. The combined effect of IAA and Pb on the volume of the vacuoles was comparable with that observed in the presence of Pb only, while for FC combined with Pb, it was additive. The use of IAA or FC together with Cd caused in both cases a decrease in the vacuole volumes by about 50%. The data presented in this study are discussed, taking into account the structure and function of the vacuolar membrane (tonoplast) and their changes in the presence of growth substances, heavy metals, and their combination.


Assuntos
Beta vulgaris , Ácidos Indolacéticos , Metais Pesados , Raízes de Plantas , Vacúolos , Beta vulgaris/crescimento & desenvolvimento , Beta vulgaris/efeitos dos fármacos , Vacúolos/efeitos dos fármacos , Vacúolos/metabolismo , Ácidos Indolacéticos/farmacologia , Metais Pesados/toxicidade , Metais Pesados/farmacologia , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Cádmio/toxicidade , Reguladores de Crescimento de Plantas/farmacologia , Chumbo/toxicidade
2.
Proc Natl Acad Sci U S A ; 121(45): e2411631121, 2024 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-39467134

RESUMO

Plasmodium falciparum malaria parasites invade and multiply inside red blood cells (RBCs), the most iron-rich compartment in humans. Like all cells, P. falciparum requires nutritional iron to support essential metabolic pathways, but the critical mechanisms of iron acquisition and trafficking during RBC infection have remained obscure. Parasites internalize and liberate massive amounts of heme during large-scale digestion of RBC hemoglobin within an acidic food vacuole (FV) but lack a heme oxygenase to release porphyrin-bound iron. Although most FV heme is sequestered into inert hemozoin crystals, prior studies indicate that trace heme escapes biomineralization and is susceptible to nonenzymatic degradation within the oxidizing FV environment to release labile iron. Parasites retain a homolog of divalent metal transporter 1 (DMT1), a known mammalian iron transporter, but its role in P. falciparum iron acquisition has not been tested. Our phylogenetic studies indicate that P. falciparum DMT1 (PfDMT1) retains conserved molecular features critical for metal transport. We localized this protein to the FV membrane and defined its orientation in an export-competent topology. Conditional knockdown of PfDMT1 expression is lethal to parasites, which display broad cellular defects in iron-dependent functions, including impaired apicoplast biogenesis and mitochondrial polarization. Parasites are selectively rescued from partial PfDMT1 knockdown by supplementation with exogenous iron, but not other metals. These results support a cellular paradigm whereby PfDMT1 is the molecular gatekeeper to essential iron acquisition by blood-stage malaria parasites and suggest that therapeutic targeting of PfDMT1 may be a potent antimalarial strategy.


Assuntos
Proteínas de Transporte de Cátions , Eritrócitos , Ferro , Malária Falciparum , Plasmodium falciparum , Proteínas de Protozoários , Plasmodium falciparum/metabolismo , Plasmodium falciparum/genética , Ferro/metabolismo , Eritrócitos/parasitologia , Eritrócitos/metabolismo , Humanos , Proteínas de Protozoários/metabolismo , Proteínas de Protozoários/genética , Malária Falciparum/parasitologia , Malária Falciparum/metabolismo , Proteínas de Transporte de Cátions/metabolismo , Proteínas de Transporte de Cátions/genética , Heme/metabolismo , Filogenia , Vacúolos/metabolismo , Animais
3.
Int J Mol Sci ; 25(20)2024 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-39456939

RESUMO

Autophagosome (AP)-lysosome/vacuole fusion is one of the hallmarks of macroautophagy. Membrane features and changes during the fusion process have mostly been described using two-dimensional (2D) models with one AP and one lysosome/vacuole. The outer membrane (OM) of a closed mature AP has been suggested to fuse with the lysosomal/vacuolar membrane. However, the descriptions in some studies for fusion-related issues are questionable or incomplete. The correct membrane features of APs and lysosomes/vacuoles are the prerequisite for describing the fusion process. We searched the literature for representative membrane features of AP-related structures based on electron microscopy (EM) graphs of both animal and yeast cells and re-evaluated the findings. We also summarized the main 2D models describing the membrane changes during AP-lysosome/vacuole fusion in the literature. We used three-dimensional (3D) models to characterize the known and unknown membrane changes during and after fusion of the most plausible 2D models. The actual situation is more complex, since multiple lysosomes may fuse with the same AP in mammalian cells, multiple APs may fuse with the same vacuole in yeast cells, and in some mutant cells, phagophores (unclosed APs) fuse with lysosomes/vacuoles. This review discusses the membrane features and highly dynamic changes during AP (phagophore)-lysosome/vacuole fusion. The resulting information will improve the understanding of AP-lysosome/vacuole fusion and direct the future research on AP-lysosome/vacuole fusion and regeneration.


Assuntos
Autofagossomos , Lisossomos , Fusão de Membrana , Vacúolos , Lisossomos/metabolismo , Autofagossomos/metabolismo , Vacúolos/metabolismo , Animais , Humanos , Membranas Intracelulares/metabolismo , Autofagia , Membrana Celular/metabolismo
4.
Commun Biol ; 7(1): 1323, 2024 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-39402183

RESUMO

Peat moss (Sphagnum) is a non-vascular higher plant with unique xylem-like hyaline (H) cells that are accompanied by photosynthetic chlorophyllous cells. These cellular structures play crucial roles in water storage and carbon sequestration. However, it is largely unknown how peat moss develops the H cells. This study systematically explored the Sphagnum Developmental Cell Atlas and Lineage and classified leaf cell development into two lineages with six stages (S0-S5) based on changes in key cellular traits, including the formation of spiral secondary cell walls (S4) and the presence of water pores (S5). Cell lineage-specific subcellular remodeling was transcriptionally regulated during leaf development, and vacuole-mediated clearance of organelles and cell death led to mature dead H cells. Interestingly, expression of land plant conserved Vascular-related NAC Domain (VND) genes correlated with H cell formation. Overall, these results suggest that the origination of xylem-like H cells is related to VND, likely through the neofunctionalization of vacuole-mediated cell death to attempt xylem formation in peat moss, suggesting potential uncoupling of xylem and phloem cell origins. This study positions peat moss as a potential model organism for studying integrative evolutionary cell biology.


Assuntos
Sphagnopsida , Vacúolos , Xilema , Xilema/metabolismo , Xilema/genética , Sphagnopsida/genética , Sphagnopsida/metabolismo , Vacúolos/metabolismo , Regulação da Expressão Gênica de Plantas , Folhas de Planta/genética , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Morte Celular , Linhagem da Célula/genética
5.
J Appl Microbiol ; 135(9)2024 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-39284782

RESUMO

AIMS: Rhodotorula mucilaginosa (Rho) can develop a range of strategies to resist the toxicity of heavy metals. This study aimed to investigate the physiological responses and transcriptomic regulation of the fungus under different heavy metal stresses. METHODS AND RESULTS: This study applied transmission electron microscopy and RNA-seq to investigate the fungal resistance to Pb, Cd, and Cu stresses. Under Pb stress, the activated autophagy-related genes, vesicle-fusing ATPase, and vacuolar ATP synthase improved vacuolar sequestration. This offsets the loss of lipids. However, the metal sequestration by vacuoles was not improved under Cd stress. Vacuolar fusion was also inhibited following the interference of intravacuolar Ca2+ due to their similar ionic radii. Cu2+ showed the maximum toxic effects due to its lowest cellular sorption (as low as 7%) with respect to Pb2+ and Cd2+, although the efflux pumps and divalent metal ion transporters partially contributed to the detoxification. CONCLUSIONS: Divalent cation transporters and vacuolar sequestration are the critical strategies for Rho to resist Pb stress. Superoxide dismutase (SOD) is the main strategy for Cd resistance in Rho. The intracellular Cu level was decreased by efflux pump and divalent metal ion transporters.


Assuntos
Metais Pesados , Rhodotorula , Vacúolos , Rhodotorula/metabolismo , Rhodotorula/genética , Vacúolos/metabolismo , Metais Pesados/metabolismo , Cádmio/metabolismo , Chumbo/metabolismo , Chumbo/toxicidade , Cobre/metabolismo , Inativação Metabólica
6.
Cell Rep ; 43(9): 114731, 2024 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-39269901

RESUMO

The Arabidopsis thaliana aluminum-activated malate transporter 9 (AtALMT9) functions as a vacuolar chloride channel that regulates the stomatal aperture. Here, we present the cryoelectron microscopy (cryo-EM) structures of AtALMT9 in three distinct states. AtALMT9 forms a dimer, and the pore is lined with four positively charged rings. The apo-AtALMT9 state shows a putative endogenous citrate obstructing the pore, where two W120 constriction residues enclose a gate with a pore radius of approximately 1.8 Å, representing an open state. Interestingly, channel closure is solely controlled by W120. Compared to wild-type plants, the W120A mutant exhibits more sensitivity to drought stress and is unable to restore the visual phenotype on leaves upon water recovery, reflecting persistent stomatal opening. Furthermore, notable variations are noted in channel gating and substrate recognition of Glycine max ALMT12, AtALMT9, and AtALMT1. In summary, our investigation enhances comprehension of the interplay between structure and function within the ALMT family.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Vacúolos , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/genética , Vacúolos/metabolismo , Transportadores de Ânions Orgânicos/metabolismo , Transportadores de Ânions Orgânicos/química , Transportadores de Ânions Orgânicos/genética , Microscopia Crioeletrônica , Mutação , Modelos Moleculares , Ativação do Canal Iônico , Canais de Cloreto
7.
New Phytol ; 244(3): 811-824, 2024 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-39238122

RESUMO

Malate and fumarate constitute a significant fraction of the carbon fixed by photosynthesis, and they are at the crossroad of central metabolic pathways. In Arabidopsis thaliana, they are transiently stored in the vacuole to keep cytosolic homeostasis. The malate and fumarate transport systems of the vacuolar membrane are key players in the control of cell metabolism. Notably, the molecular identity of these transport systems remains mostly unresolved. We used a combination of imaging, electrophysiology and molecular physiology to identify an important molecular actor of dicarboxylic acid transport across the tonoplast. Here, we report the function of the A. thaliana Aluminium-Activated Malate Transporter 5 (AtALMT5). We characterised its ionic transport properties, expression pattern, localisation and function in vivo. We show that AtALMT5 is expressed in photosynthetically active tissues and localised in the tonoplast. Patch-clamp and in planta analyses demonstrated that AtALMT5 is an ion channel-mediating fumarate loading of the vacuole. We found in almt5 plants a reduced accumulation of fumarate in the leaves, in parallel with increased malate concentrations. These results identified AtALMT5 as an ion channel-mediating fumarate transport in the vacuoles of mesophyll cells and regulating the malate/fumarate balance in Arabidopsis.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Fumaratos , Malatos , Transportadores de Ânions Orgânicos , Vacúolos , Arabidopsis/metabolismo , Arabidopsis/genética , Malatos/metabolismo , Fumaratos/metabolismo , Vacúolos/metabolismo , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Transportadores de Ânions Orgânicos/metabolismo , Transportadores de Ânions Orgânicos/genética , Transporte Biológico , Regulação da Expressão Gênica de Plantas , Células do Mesofilo/metabolismo , Folhas de Planta/metabolismo
8.
EMBO Rep ; 25(10): 4358-4386, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39242777

RESUMO

Plants evolve nucleotide-binding leucine-rich repeat receptors (NLRs) to induce immunity. Activated coiled-coil (CC) domain containing NLRs (CNLs) oligomerize and form apparent cation channels promoting calcium influx and cell death, with the alpha-1 helix of the individual CC domains penetrating the plasma membranes. Some CNLs are characterized by putative N-myristoylation and S-acylation sites in their CC domain, potentially mediating permanent membrane association. Whether activated Potentially Membrane Localized NLRs (PMLs) mediate cell death and calcium influx in a similar way is unknown. We uncovered the cell-death function at the vacuole of an atypical but conserved Arabidopsis PML, PML5, which has a significant deletion in its CCG10/GA domain. Active PML5 oligomers localize in Golgi membranes and the tonoplast, alter vacuolar morphology, and induce cell death, with the short N-terminus being sufficient. Mutant analysis supports a potential role of PMLs in plant immunity. PML5-like deletions are found in several Brassicales paralogs, pointing to the evolutionary importance of this innovation. PML5, with its minimal CC domain, represents the first identified CNL utilizing vacuolar-stored calcium for cell death induction.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Morte Celular , Vacúolos , Vacúolos/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Morte Celular/genética , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Proteínas NLR/genética , Proteínas NLR/metabolismo , Deleção de Sequência , Imunidade Vegetal/genética , Domínios Proteicos , Sequência de Aminoácidos
9.
Plant Cell ; 36(11): 4683-4691, 2024 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-39305130

RESUMO

Plant vacuoles play key roles in cellular homeostasis, performing catabolic and storage functions, and regulating pH and ion balance. Despite their essential role, there is still no consensus on how vacuoles are established. A model proposing that the endoplasmic reticulum is the main contributor of membrane for growing vacuoles in meristematic cells has been challenged by a study proposing that plant vacuoles are formed de novo by homotypic fusion of multivesicular bodies (MVBs). Here, we use the Arabidopsis thaliana root as a model system to provide a systematic overview of successive vacuole biogenesis stages, starting from the youngest cells proximate to the quiescent center. We combine in vivo high- and super-resolution (STED) microscopy to demonstrate the presence of tubular and connected vacuolar structures in all meristematic cells. Using customized fluorescence recovery after photobleaching (FRAP) assays, we establish different modes of connectivity and demonstrate that thin, tubular vacuoles, as observed in cells near the quiescent center, form an interconnected network. Finally, we argue that a growing body of evidence indicates that vacuolar structures cannot originate from MVBs alone but receive membrane material from different sources simultaneously.


Assuntos
Arabidopsis , Recuperação de Fluorescência Após Fotodegradação , Meristema , Vacúolos , Vacúolos/metabolismo , Arabidopsis/citologia , Recuperação de Fluorescência Após Fotodegradação/métodos , Meristema/citologia , Raízes de Plantas/citologia , Células Vegetais
10.
Biochem Biophys Res Commun ; 734: 150628, 2024 11 19.
Artigo em Inglês | MEDLINE | ID: mdl-39232457

RESUMO

Microautophagy degrades cargos in the vacuole by direct engulfment of the vacuolar membrane. Micronucleophagy selectively degrades a portion of the nucleus in budding yeast. The vacuole contacts the nucleus via the nucleus-vacuole junction (NVJ), and in micronucleophagy a portion of the nucleus containing nucleolar proteins is made to protrude into the vacuole at the NVJ, followed by abscission and degradation. Microautophagy and micronucleophagy are induced by inactivation of target of rapamycin complex 1 (TORC1) protein kinase after nutrient starvation. Here, we show that the VAMP-associated proteins (VAPs) Scs2 and its paralog Scs22 are required for NVJ integrity and micronucleophagic degradation of nucleolar proteins. On the other hand, nucleolar dynamics prerequisite for micronucleophagy were not impaired in VAP mutant cells. Finally, yeast VAPs were critical for viability during prolonged nutrient starvation. This study sheds light on the emerging role of VAP in adaptation in responses to nutrient starvation.


Assuntos
Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae , Autofagia , Núcleo Celular/metabolismo , Microautofagia , Proteínas R-SNARE/metabolismo , Proteínas R-SNARE/genética , Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Vacúolos/metabolismo
11.
Biosci Biotechnol Biochem ; 88(11): 1279-1288, 2024 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-39231809

RESUMO

Fungal biosynthetic gene clusters often include genes encoding transmembrane proteins, which have been mostly thought to be transporters exporting the products. However, there is little knowledge about subcellular compartmentalization of transmembrane proteins essential for biosynthesis. Fungal mycotoxin cyclochlorotine is synthesized by non-ribosomal peptide synthetase, which is followed by modifications with three transmembrane UstYa-family proteins. Heterologous expression in Aspergillus oryzae revealed that total biosynthesis of cyclochlorotine requires additional two transporter proteins. Here, we investigated subcellular localizations of the five transmembrane proteins under heterologous expression in A. oryzae. Enhanced green fluorescent protein (EGFP) fusions to the transmembrane proteins, which were confirmed to normally function in cyclochlorotine production, were expressed together with organellar markers. All the transmembrane proteins exhibited localizations commonly in line of the trans-Golgi, endosomes, and vacuoles. This study suggests that subcellular compartmentalization of UstYa family proteins and transporters allows corporative functions of delivering intermediates and subsequent modifications, completing cyclochlorotine biosynthesis.


Assuntos
Aspergillus oryzae , Peptídeos Cíclicos , Peptídeos Cíclicos/biossíntese , Peptídeos Cíclicos/metabolismo , Peptídeos Cíclicos/química , Aspergillus oryzae/metabolismo , Aspergillus oryzae/genética , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Proteínas Fúngicas/metabolismo , Proteínas Fúngicas/genética , Proteínas de Membrana/metabolismo , Proteínas de Membrana/genética , Peptídeo Sintases/metabolismo , Peptídeo Sintases/genética , Vacúolos/metabolismo , Complexo de Golgi/metabolismo , Proteínas Recombinantes de Fusão/metabolismo , Proteínas Recombinantes de Fusão/genética , Endossomos/metabolismo
12.
Mol Biol Cell ; 35(11): br20, 2024 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-39259764

RESUMO

The vacuolar-type H+-translocating ATPase (V-ATPase) is the major proton pump for intraorganellar acidification. Therefore, the integrity of the V-ATPase is closely associated with cellular homeostasis, and mutations in genes encoding V-ATPase components and assembly factors have been reported in certain types of diseases. For instance, the recurrent mutations of ATP6AP1, a gene encoding a V-ATPase accessory protein, have been associated with cancers and immunodeficiency. With the aim of studying V-ATPase-related mutations using the yeast model system, we report that Big1 is another homologue of ATP6AP1 in yeast cells, and we characterize the role of Big1 in maintaining a fully functional V-ATPase. In addition to its role in acidifying the vacuole or lysosome, our data support the concept that the V-ATPase may function as part of a signaling pathway to regulate macroautophagy/autophagy through a mechanism that is independent from Tor/MTOR.


Assuntos
Autofagia , Lisossomos , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae , ATPases Vacuolares Próton-Translocadoras , Vacúolos , ATPases Vacuolares Próton-Translocadoras/metabolismo , ATPases Vacuolares Próton-Translocadoras/genética , Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/genética , Lisossomos/metabolismo , Vacúolos/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Mutação/genética , Transdução de Sinais , Serina-Treonina Quinases TOR/metabolismo
13.
Nat Commun ; 15(1): 8414, 2024 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-39341826

RESUMO

Typhoidal Salmonella enterica serovars, such as Typhi and Paratyphi A, cause severe systemic infections, thereby posing a significant threat as human-adapted pathogens. This study focuses on cytolysin A (ClyA), a virulence factor essential for bacterial dissemination within the human body. We show that ClyA is exclusively expressed by intracellular S. Paratyphi A within the Salmonella-containing vacuole (SCV), regulated by the PhoP/Q system and SlyA. ClyA localizes in the bacterial periplasm, suggesting potential secretion. Deletion of TtsA, an essential Type 10 Secretion System component, completely abolishes intracellular ClyA detection and its presence in host cell supernatants. Host cells infected with wild-type S. Paratyphi A contain substantial ClyA, with supernatants capable of lysing neighboring cells. Notably, ClyA selectively lyses macrophages and erythrocytes while sparing epithelial cells. These findings identify ClyA as an intracellularly induced cytolysin, dependent on the SCV environment and secreted via a Type 10 Secretion System, with specific cytolytic activity.


Assuntos
Proteínas de Bactérias , Salmonella paratyphi A , Vacúolos , Humanos , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/genética , Animais , Camundongos , Vacúolos/metabolismo , Salmonella paratyphi A/metabolismo , Macrófagos/microbiologia , Macrófagos/metabolismo , Perforina/metabolismo , Perforina/genética , Salmonella typhi/metabolismo , Fatores de Virulência/metabolismo , Eritrócitos/metabolismo , Citotoxinas/metabolismo , Células Epiteliais/metabolismo , Células Epiteliais/microbiologia , Sistemas de Secreção Bacterianos/metabolismo , Sistemas de Secreção Bacterianos/genética , Regulação Bacteriana da Expressão Gênica
14.
Zhonghua Bing Li Xue Za Zhi ; 53(9): 910-915, 2024 Sep 08.
Artigo em Chinês | MEDLINE | ID: mdl-39231743

RESUMO

Objective: To investigate the clinicopathological features and differential diagnosis of eosinophilic vacuolated tumor (EVT). Methods: Seven cases of EVT with characteristic morphology and unequivocal diagnosis from the Affiliated Hospital of Qingdao University (6 cases), Qingdao, China and the 971 Hospital of PLA Navy (1 case), Qingdao, China between January 2010 and December 2021 were subject to morphological and immunohistochemical analyses. Additionally, whole exome sequencing (WES) was performed in two cases. Twenty-two cases of renal oncocytoma (RO) and 17 cases of eosinophilic chromophobe renal cell carcinoma (eChRCC) diagnosed at the same time were used as controls. Results: Four males and three females with a mean age of 42 years (range: 29-61 years) were included in the study. The tumors were nodular and well-circumscribed, with sizes ranging from 1.5 to 4.5 cm. On cross-section, they appeared gray-red or gray-white, solid, and soft. Tumor cells were arranged in nests, solid sheets, and acinar or small vesicular structures. These cells exhibited eosinophilic cytoplasm with large, prominent clear vacuoles and round nuclei with prominent nucleoli. Perinuclear halos were focally present in four cases, while small tumor cells with sparse cytoplasm and hyperchromatic nuclei were seen in one case. No necrosis or mitosis was noted. Edematous stroma was detected in three cases. All tumors were positive for CD117 and Cathepsin K, but negative for vimentin and CK7. CK20 was positive in scattered individual cells, and Ki-67 positivity ranged from 1% to 4%. Point mutations in MTOR were identified in both patients who were subject to the molecular analysis. Statistical differences in the expression of Cathepsin K, CD10, S-100A1, and Cyclin D1 between EVT and RO (P<0.05) were significant, so were the differences in the expression of Cathepsin K, CD10, CK7 and claudin 7 between EVT and eChRCC (P<0.001). Seven patients were followed up for 4 to 96 months (mean, 50 months), with no recurrences or metastases. Conclusions: EVT is a rare renal tumor that shares morphological and immunophenotypic features with RO and eChRCC, and it is closely linked to the TSC/MTOR pathway. The presence of large prominent transparent vacuoles in eosinophilic cytoplasm along with conspicuous nucleoli is its key morphological characteristics. The use of combined immunohistochemical stains greatly aids in its diagnosis. Typically, the tumor exhibits indolent biological behaviors with a favorable prognosis.


Assuntos
Carcinoma de Células Renais , Neoplasias Renais , Humanos , Masculino , Feminino , Pessoa de Meia-Idade , Adulto , Neoplasias Renais/patologia , Neoplasias Renais/metabolismo , Neoplasias Renais/genética , Carcinoma de Células Renais/patologia , Carcinoma de Células Renais/metabolismo , Carcinoma de Células Renais/genética , Diagnóstico Diferencial , Vacúolos/patologia , Eosinófilos/patologia , Eosinofilia/patologia , Eosinofilia/metabolismo
15.
Dev Cell ; 59(17): 2273-2274, 2024 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-39255771

RESUMO

In this issue of Developmental Cell, Jiang et al. report that the Arabidopsis HOPS tethering complex subunit VPS41 acts to catalyze the formation of a degradation pathway composed of a hybrid of autophagosomes and late endosomes.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Autofagossomos , Autofagia , Endossomos , Vacúolos , Arabidopsis/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Autofagossomos/metabolismo , Autofagia/fisiologia , Endossomos/metabolismo , Vacúolos/metabolismo , Proteínas de Transporte Vesicular/metabolismo , Proteínas de Transporte Vesicular/genética
16.
Front Cell Infect Microbiol ; 14: 1442995, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39310786

RESUMO

Chlamydia are Gram-negative, obligate intracellular bacterial pathogens that infect eukaryotic cells and reside within a host-derived vacuole known as the inclusion. To facilitate intracellular replication, these bacteria must engage in host-pathogen interactions to obtain nutrients and membranes required for the growth of the inclusion, thereby sustaining prolonged bacterial colonization. Autophagy is a highly conserved process that delivers cytoplasmic substrates to the lysosome for degradation. Pathogens have developed strategies to manipulate and/or exploit autophagy to promote their replication and persistence. This review delineates recent advances in elucidating the interplay between Chlamydia trachomatis infection and autophagy in recent years, emphasizing the intricate strategies employed by both the Chlamydia pathogens and host cells. Gaining a deeper understanding of these interactions could unveil novel strategies for the prevention and treatment of Chlamydia infection.


Assuntos
Autofagia , Infecções por Chlamydia , Chlamydia trachomatis , Interações Hospedeiro-Patógeno , Autofagia/fisiologia , Chlamydia trachomatis/patogenicidade , Chlamydia trachomatis/fisiologia , Humanos , Infecções por Chlamydia/microbiologia , Vacúolos/microbiologia , Animais , Lisossomos/microbiologia , Lisossomos/metabolismo
17.
New Phytol ; 244(3): 840-854, 2024 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-39262026

RESUMO

Style penetration by pollen tubes is essential for reproductive success, a process requiring canonical Rab5s in Arabidopsis. However, functional loss of Arabidopsis Vps9a, the gene encoding for guanine nucleotide exchange factor (GEF) of Rab5s, did not affect male transmission, implying the presence of a compensation program or redundancy. By combining genetic, cytological, and molecular approaches, we report that Arabidopsis Vps9b is a pollen-preferential gene, redundantly mediating pollen tube penetration of style with Vps9a. Vps9b is functionally interchangeable with Vps9a, whose functional distinction results from distinct expression profiles. Functional loss of Vps9a and Vps9b results in the mis-targeting of Rab5-dependent tonoplast proteins, defective vacuolar biogenesis, disturbed distribution of post-Golgi vesicles, increased cellular turgor, cytosolic acidification, and disrupted organization of actin microfilaments (MF) in pollen tubes, which collectively lead to the failure of pollen tubes to grow through style.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Regulação da Expressão Gênica de Plantas , Tubo Polínico , Isoformas de Proteínas , Vacúolos , Tubo Polínico/crescimento & desenvolvimento , Tubo Polínico/genética , Tubo Polínico/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Isoformas de Proteínas/metabolismo , Isoformas de Proteínas/genética , Vacúolos/metabolismo , Citoesqueleto de Actina/metabolismo , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Fatores de Troca do Nucleotídeo Guanina/genética , Complexo de Golgi/metabolismo , Mutação/genética
19.
Pathog Dis ; 822024 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-39138067

RESUMO

Coxiella burnetii is a globally distributed obligate intracellular pathogen. Although often asymptomatic, infections can cause acute Q fever with influenza-like symptoms and/or severe chronic Q fever. Coxiella burnetii develops a unique replicative niche within host cells called the Coxiella-containing vacuole (CCV), facilitated by the Dot/Icm type IV secretion system translocating a cohort of bacterial effector proteins into the host. The role of some effectors has been elucidated; however, the actions of the majority remain enigmatic and the list of true effectors is disputable. This study examined CBU2016, a unique C. burnetii protein previously designated as an effector with a role in infection. We were unable to validate CBU2016 as a translocated effector protein. Employing targeted knock-out and complemented strains, we found that the loss of CBU2016 did not cause a replication defect within Hela, THP-1, J774, or iBMDM cells or in axenic media, nor did it affect the pathogenicity of C. burnetii in the Galleria mellonella infection model. The absence of CBU2016 did, however, result in a consistent decrease in the size of CCVs in HeLa cells. These results suggest that although CBU2016 may not be a Dot/Icm effector, it is still able to influence the host environment during infection.


Assuntos
Proteínas de Bactérias , Coxiella burnetii , Febre Q , Vacúolos , Coxiella burnetii/genética , Coxiella burnetii/metabolismo , Coxiella burnetii/patogenicidade , Humanos , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/genética , Vacúolos/microbiologia , Vacúolos/metabolismo , Animais , Febre Q/microbiologia , Células HeLa , Linhagem Celular , Fatores de Virulência/metabolismo , Fatores de Virulência/genética , Técnicas de Inativação de Genes , Mariposas/microbiologia , Interações Hospedeiro-Patógeno , Células THP-1
20.
Methods Mol Biol ; 2845: 15-25, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39115654

RESUMO

The selective degradation of nuclear components via autophagy, termed nucleophagy, is an essential process observed from yeasts to mammals and crucial for maintaining nucleus homeostasis and regulating nucleus functions. In the budding yeast Saccharomyces cerevisiae, nucleophagy occurs in two different manners: one involves autophagosome formation for the sequestration and vacuolar transport of nucleus-derived vesicles (NDVs), and the other proceeds with the invagination of the vacuolar membrane for the uptake of NDVs into the vacuole, termed macronucleophagy and micronucleophagy, respectively. This chapter describes methods to analyze and quantify activities of these nucleophagy pathways in yeast.


Assuntos
Autofagia , Núcleo Celular , Saccharomyces cerevisiae , Vacúolos , Saccharomyces cerevisiae/metabolismo , Vacúolos/metabolismo , Núcleo Celular/metabolismo , Autofagia/fisiologia , Autofagossomos/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...