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1.
MicroPubl Biol ; 20222022.
Artigo em Inglês | MEDLINE | ID: mdl-35224461

RESUMO

Fungal infection triggers the induction of antimicrobial peptide (AMP) genes in the epidermis (Pujol et al, 2008). We previously showed that this effect is suppressed by the mitochondrial unfolded protein response (UPRmt), which can be activated by knockdown of select genes including the mitochondrial metalloprotease spg-7 (Zugasti et al, 2016). Here, we confirm that RNAi against spg-7 triggers the UPRmt and blocks AMP induction during infection, whereas infection itself does not trigger the UPRmt. ATFS-1 is a key factor in the UPRmt, mediating much of the associated transcriptional response. We find that, surprisingly, ATFS-1 is not required for the suppression of AMP induction provoked by spg-7(RNAi). These data show that the mitochondrial dysfunction that blocks the immune response upon infection or wounding is independent of ATFS-1.

2.
Curr Top Dev Biol ; 144: 309-351, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33992157

RESUMO

In its natural habitat, C. elegans encounters a wide variety of microbes, including food, commensals and pathogens. To be able to survive long enough to reproduce, C. elegans has developed a complex array of responses to pathogens. These activities are coordinated on scales that range from individual organelles to the entire organism. Often, the response is triggered within cells, by detection of infection-induced damage, mainly in the intestine or epidermis. C. elegans has, however, a capacity for cell non-autonomous regulation of these responses. This frequently involves the nervous system, integrating pathogen recognition, altering host biology and governing avoidance behavior. Although there are significant differences with the immune system of mammals, some mechanisms used to limit pathogenesis show remarkable phylogenetic conservation. The past 20 years have witnessed an explosion of host-pathogen interaction studies using C. elegans as a model. This review will discuss the broad themes that have emerged and highlight areas that remain to be fully explored.


Assuntos
Caenorhabditis elegans , Imunidade Inata , Animais , Caenorhabditis elegans/genética , Filogenia
3.
PLoS Comput Biol ; 16(7): e1008002, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32692770

RESUMO

Ageing affects a wide range of phenotypes at all scales, but an objective measure of ageing remains challenging, even in simple model organisms. To measure the ageing process, we characterized the sequence of alterations of multiple phenotypes at organismal scale. Hundreds of morphological, postural, and behavioral features were extracted from high-resolution videos. Out of the 1019 features extracted, 896 are ageing biomarkers, defined as those that show a significant correlation with relative age (age divided by lifespan). We used support vector regression to predict age, remaining life and lifespan of individual C. elegans. The quality of these predictions (age R2 = 0.79; remaining life R2 = 0.77; lifespan R2 = 0.72) increased with the number of features added to the model, supporting the use of multiple features to quantify ageing. We quantified the rate of ageing as how quickly animals moved through a phenotypic space; we quantified health decline as the slope of the declining predicted remaining life. In both ageing dimensions, we found that short lived-animals aged faster than long-lived animals. In our conditions, for isogenic wild-type worms, the health decline of the individuals was scaled to their lifespan without significant deviation from the average for short- or long-lived animals.


Assuntos
Caenorhabditis elegans/fisiologia , Longevidade , Fenótipo , Algoritmos , Animais , Comportamento Animal , Biomarcadores/metabolismo , Proteínas de Caenorhabditis elegans/metabolismo , Biologia Computacional , Simulação por Computador , Mutação , Estresse Oxidativo , Prognóstico , Análise de Regressão , Reprodutibilidade dos Testes , Estresse Mecânico , Fatores de Tempo , Gravação em Vídeo
5.
Mol Cell ; 65(6): 1096-1108.e6, 2017 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-28306505

RESUMO

Protein aggregation is associated with age-related neurodegenerative disorders, such as Alzheimer's and polyglutamine diseases. As a causal relationship between protein aggregation and neurodegeneration remains elusive, understanding the cellular mechanisms regulating protein aggregation will help develop future treatments. To identify such mechanisms, we conducted a forward genetic screen in a C. elegans model of polyglutamine aggregation and identified the protein MOAG-2/LIR-3 as a driver of protein aggregation. In the absence of polyglutamine, MOAG-2/LIR-3 regulates the RNA polymerase III-associated transcription of small non-coding RNAs. This regulation is lost in the presence of polyglutamine, which mislocalizes MOAG-2/LIR-3 from the nucleus to the cytosol. We then show biochemically that MOAG-2/LIR-3 can also catalyze the aggregation of polyglutamine-expanded huntingtin. These results suggest that polyglutamine can induce an aggregation-promoting activity of MOAG-2/LIR-3 in the cytosol. The concept that certain aggregation-prone proteins can convert other endogenous proteins into drivers of aggregation and toxicity adds to the understanding of how cellular homeostasis can be deteriorated in protein misfolding diseases.


Assuntos
Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/enzimologia , Doenças Neurodegenerativas/enzimologia , Peptídeos/metabolismo , Agregados Proteicos , Agregação Patológica de Proteínas , RNA Polimerase III/metabolismo , Fatores de Transcrição/metabolismo , Transporte Ativo do Núcleo Celular , Animais , Animais Geneticamente Modificados , Sítios de Ligação , Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/genética , Núcleo Celular/enzimologia , Citosol/enzimologia , Modelos Animais de Doenças , Doenças Neurodegenerativas/genética , Doenças Neurodegenerativas/patologia , Regiões Promotoras Genéticas , Ligação Proteica , Interferência de RNA , RNA Polimerase III/genética , Pequeno RNA não Traduzido/genética , Pequeno RNA não Traduzido/metabolismo , Fatores de Transcrição/genética , Transcrição Gênica
6.
Sci Rep ; 6: 39199, 2016 12 20.
Artigo em Inglês | MEDLINE | ID: mdl-27995966

RESUMO

The enzyme TDO (tryptophan 2,3-dioxygenase; TDO-2 in Caenorhabditis elegans) is a potential therapeutic target to cancer but is also thought to regulate proteotoxic events seen in the progression of neurodegenerative diseases. To better understand its function and develop specific compounds that target TDO we need to understand the structure of this molecule. In C. elegans we compared multiple different CRISPR/Cas9-induced tdo-2 deletion mutants and identified a motif of three amino acids (PLD) that is required for the enzymatic conversion of tryptophan to N-formylkynurenine. Loss of TDO-2's enzymatic activity in PDL deletion mutants was accompanied by an increase in motility during aging and a prolonged lifespan, which is in line with the previously observed phenotypes induced by a knockdown of the full enzyme. Comparison of sequence structures suggests that blocking this motif might interfere with haem binding, which is essential for the enzyme's activity. The fact that these three residues are situated in an evolutionary conserved structural loop of the enzyme suggests that the findings can be translated to humans. The identification of this specific loop region in TDO-2-essential for its catalytic function-will aid in the design of novel inhibitors to treat diseases in which the TDO enzyme is overexpressed or hyperactive.


Assuntos
Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/enzimologia , Evolução Molecular , Triptofano Oxigenase/metabolismo , Envelhecimento , Motivos de Aminoácidos , Sequência de Aminoácidos , Animais , Sistemas CRISPR-Cas/genética , Proteínas de Caenorhabditis elegans/química , Proteínas de Caenorhabditis elegans/genética , Heme/química , Heme/metabolismo , Humanos , Locomoção , Longevidade , Mutagênese , Ligação Proteica , Estrutura Terciária de Proteína , Alinhamento de Sequência , Triptofano Oxigenase/química , Triptofano Oxigenase/genética
7.
Cell Stress Chaperones ; 17(2): 229-41, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22038197

RESUMO

The carboxyl terminus of Hsc70-interacting protein (CHIP) is an Hsp70 co-chaperone and a U-box ubiquitin ligase that plays a crucial role in protein quality control in higher eukaryotes. The yeast Yarrowia lipolytica is the only known hemiascomycete where a CHIP ortholog is found. Here, we characterize Y. lipolytica's CHIP ortholog (Yl.Chn1p) and document its interactions with components of the protein quality control machinery. We show that Yl.Chn1p is non-essential unless Y. lipolytica is severely stressed. We sought for genetic interactions among key components of the Y. lipolytica protein quality control arsenal, including members of the Ssa-family of Hsp70 molecular chaperones, the Yl.Bag1p Hsp70 nucleotide exchange factor, the Yl.Chn1p and Yl.Ufd2p U-box ubiquitin ligases, the Yl.Doa10p and Yl.Hrd1p RING-finger ubiquitin ligases, and the Yl.Hsp104p disaggregating molecular chaperone. Remarkably, no synthetic phenotypes were observed among null alleles of the corresponding genes in most cases, suggesting that overlapping pathways efficiently act to enable Y. lipolytica cells to survive under harsh conditions. Yl.Chn1p interacts with mammalian and Saccharomyces cerevisiae members of the Hsp70 family in vitro, and these interactions are differently regulated by Hsp70 co-chaperones. We demonstrate notably that Yl.Chn1p/Ssa1p interaction is Fes1p-dependent and the formation of an Yl.Chn1p/Ssa1p/Sse1p ternary complex. Finally, we show that, similar to Sse1p, Yl.Chn1p can act as a "holdase" to prevent the aggregation of a heat-denatured protein.


Assuntos
Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismo , Yarrowia/genética , Yarrowia/metabolismo , Sequência de Aminoácidos , Western Blotting , Proteínas de Choque Térmico HSC70/química , Proteínas de Choque Térmico HSC70/genética , Proteínas de Choque Térmico HSC70/metabolismo , Temperatura Alta , Dados de Sequência Molecular , Análise Serial de Proteínas , Alinhamento de Sequência , Fatores de Tempo , Ubiquitina-Proteína Ligases/química , Yarrowia/química
8.
FEBS Lett ; 584(6): 1149-55, 2010 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-20138883

RESUMO

The yeast Saccharomyces cerevisiae is able to form complex multicellular structures called mats on low-density agar Petri plates. Mat formation strictly depends on Flo11p, a cell surface mannoprotein that mediates the adhesion of yeast cells to the agar surface. Here, we show that Swa2p, an auxilin ortholog required for clathrin-coated vesicle uncoating, is strictly required for biofilm formation. We show that the maturation and cellular levels of Flo11p are affected in Deltaswa2 cells, yet without compromising invasive growth. Both the TPR and J-domains of Swa2p, but not its clathrin-binding and ubiquitin-association motifs, are required for its function in Flo11p processing.


Assuntos
Comunicação Celular/fisiologia , Clatrina/metabolismo , Glicoproteínas de Membrana/metabolismo , Fosfoproteínas/fisiologia , Proteínas de Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/fisiologia , Saccharomyces cerevisiae/fisiologia , Proteínas de Transporte Vesicular/fisiologia , Proteínas Adaptadoras de Transporte Vesicular/metabolismo , Sítios de Ligação/genética , Adesão Celular/genética , Adesão Celular/fisiologia , Comunicação Celular/genética , Deleção de Genes , Organismos Geneticamente Modificados , Fosfoproteínas/química , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , Ligação Proteica/genética , Processamento de Proteína Pós-Traducional/genética , Estrutura Terciária de Proteína/genética , Estrutura Terciária de Proteína/fisiologia , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/genética , Ubiquitina/metabolismo , Proteínas de Transporte Vesicular/química , Proteínas de Transporte Vesicular/genética , Proteínas de Transporte Vesicular/metabolismo
9.
PLoS One ; 4(8): e6644, 2009 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-19680550

RESUMO

BACKGROUND: The cytosol of most eukaryotic cells contains multiple highly conserved Hsp70 orthologs that differ mainly by their spatio-temporal expression patterns. Hsp70s play essential roles in protein folding, transport or degradation, and are major players of cellular quality control processes. However, while several reports suggest that specialized functions of Hsp70 orthologs were selected through evolution, few studies addressed systematically this issue. METHODOLOGY/PRINCIPAL FINDINGS: We compared the ability of Ssa1p-Ssa4p from Saccharomyces cerevisiae and Ssa5p-Ssa8p from the evolutionary distant yeast Yarrowia lipolytica to perform Hsp70-dependent tasks when expressed as the sole Hsp70 for S. cerevisiae in vivo. We show that Hsp70 isoforms (i) supported yeast viability yet with markedly different growth rates, (ii) influenced the propagation and stability of the [PSI(+)] and [URE3] prions, but iii) did not significantly affect the proteasomal degradation rate of CFTR. Additionally, we show that individual Hsp70 orthologs did not induce the formation of different prion strains, but rather influenced the aggregation properties of Sup35 in vivo. Finally, we show that [URE3] curing by the overexpression of Ydj1p is Hsp70-isoform dependent. CONCLUSION/SIGNIFICANCE: Despite very high homology and overlapping functions, the different Hsp70 orthologs have evolved to possess distinct activities that are required to cope with different types of substrates or stress situations. Yeast prions provide a very sensitive model to uncover this functional specialization and to explore the intricate network of chaperone/co-chaperone/substrates interactions.


Assuntos
Divisão Celular , Proteínas Fúngicas/fisiologia , Proteínas de Choque Térmico HSP70/fisiologia , Príons , Saccharomyces cerevisiae/fisiologia , Yarrowia/fisiologia , Biopolímeros , Microscopia de Fluorescência , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Saccharomyces cerevisiae/citologia , Especificidade da Espécie
10.
Curr Genomics ; 9(5): 338-248, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-19471609

RESUMO

Hsp70 molecular chaperones play a variety of functions in every organism, cell type and organelle, and their activities have been implicated in a number of human pathologies, ranging from cancer to neurodegenerative diseases. The functions, regulations and structure of Hsp70s were intensively studied for about three decades, yet much still remains to be learned about these essential folding enzymes. Genome sequencing efforts revealed that most genomes contain multiple members of the Hsp70 family, some of which co-exist in the same cellular compartment. For example, the human cytosol and nucleus contain six highly homologous Hsp70 proteins while the yeast Saccharomyces cerevisiae contains four canonical Hsp70s and three fungal-specific ribosome-associated and specialized Hsp70s. The reasons and significance of the requirement for multiple Hsp70s is still a subject of debate. It has been postulated for a long time that these Hsp70 isoforms are functionally redundant and differ only by their spatio-temporal expression patterns. However, several studies in yeast and higher eukaryotic organisms challenged this widely accepted idea by demonstrating functional specificity among Hsp70 isoforms. Another element of complexity is brought about by specific cofactors, such as Hsp40s or nucleotide exchange factors that modulate the activity of Hsp70s and their binding to client proteins. Hence, a dynamic network of chaperone/co-chaperone interactions has evolved in each organism to efficiently take advantage of the multiple cellular roles Hsp70s can play. We summarize here our current knowledge of the functions and regulations of these molecular chaperones, and shed light on the known functional specificities among isoforms.

11.
Genetics ; 177(3): 1679-89, 2007 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-17947402

RESUMO

The yeast Saccharomyces cerevisiae has been used as a model for fungal biofilm formation due to its ability to adhere to plastic surfaces and to form mats on low-density agar petri plates. Mats are complex multicellular structures composed of a network of cables that form a central hub from which emanate multiple radial spokes. This reproducible and elaborate pattern is indicative of a highly regulated developmental program that depends on specific transcriptional programming, environmental cues, and possibly cell-cell communication systems. While biofilm formation and sliding motility were shown to be strictly dependent on the cell-surface adhesin Flo11p, little is known about the cellular machinery that controls mat formation. Here we show that Hsp70 molecular chaperones play key roles in this process with the assistance of the nucleotide exchange factors Fes1p and Sse1p and the Hsp40 family member Ydj1p. The disruption of these cofactors completely abolished mat formation. Furthermore, complex interactions among SSA genes were observed: mat formation depended mostly on SSA1 while minor defects were observed upon loss of SSA2; additional mutations in SSA3 or SSA4 further enhanced these phenotypes. Importantly, these mutations did not compromise invasive growth or Flo11p expression, suggesting that Flo11p-independent pathways are necessary to form mats.


Assuntos
Proteínas de Choque Térmico HSP70/fisiologia , Proteínas de Membrana/fisiologia , Proteínas de Saccharomyces cerevisiae/fisiologia , Saccharomyces cerevisiae/fisiologia , Aderência Bacteriana , Biofilmes/crescimento & desenvolvimento , Genes Fúngicos , Proteínas de Choque Térmico HSP110/genética , Proteínas de Choque Térmico HSP110/fisiologia , Proteínas de Choque Térmico HSP40/genética , Proteínas de Choque Térmico HSP40/fisiologia , Proteínas de Choque Térmico HSP70/genética , Peptídeos e Proteínas de Sinalização Intracelular/genética , Peptídeos e Proteínas de Sinalização Intracelular/fisiologia , Glicoproteínas de Membrana , Proteínas de Membrana/genética , Modelos Biológicos , Mutação , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética
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