13 results on '"Žárský, Viktor"'
Search Results
2. RIN4 recruits the exocyst subunit EXO70B1 to the plasma membrane
- Author
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Sabol, Peter, Kulich, Ivan, and Žárský, Viktor
- Published
- 2017
3. Three subfamilies of exocyst EXO70 family subunits in land plants: early divergence and ongoing functional specialization.
- Author
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Žárský, Viktor, Sekereš, Juraj, Kubátová, Zdeňka, Pečenková, Tamara, and Cvrčková, Fatima
- Subjects
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PLANT genomes , *PLANT membranes , *CELL membranes , *CANONICAL correlation (Statistics) , *PLASMA cells , *ENDOCYTOSIS - Abstract
Localized delivery of plasma membrane and cell wall components is an essential process in all plant cells. The vesicle-tethering complex, the exocyst, an ancient eukaryotic hetero-octameric protein cellular module, assists in targeted delivery of exocytosis vesicles to specific plasma membrane domains. Analyses of Arabidopsis and later other land plant genomes led to the surprising prediction of multiple putative EXO70 exocyst subunit paralogues. All land plant EXO70 exocyst subunits (including those of Bryophytes) form three distinct subfamilies—EXO70.1, EXO70.2, and EXO70.3. Interestingly, while the basal well-conserved EXO70.1 subfamily consists of multiexon genes, the remaining two subfamilies contain mostly single exon genes. Published analyses as well as public transcriptomic and proteomic data clearly indicate that most cell types in plants express and also use several different EXO70 isoforms. Here we sum up recent advances in the characterization of the members of the family of plant EXO70 exocyst subunits and present evidence that members of the EXO70.2 subfamily are often recruited to non-canonical functions in plant membrane trafficking pathways. Engagement of the most evolutionarily dynamic EXO70.2 subfamily of EXO70s in biotic interactions and defence correlates well with massive proliferation and conservation of new protein variants in this subfamily. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
4. Constitutive Negative Regulation of R Proteins in Arabidopsis also via Autophagy Related Pathway?
- Author
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Pečenková, Tamara, Sabol, Peter, Kulich, Ivan, Ortmannová, Jitka, and Žárský, Viktor
- Subjects
resistance ,Avr ,autophagy ,exocyst ,ETI ,Plant Science ,lesions ,dwarf - Abstract
Even though resistance (R) genes are among the most studied components of the plant immunity, there remain still a lot of aspects to be explained about the regulation of their function. Many gain-of-function mutants of R genes and loss-of-function of their regulators often demonstrate up-regulated defense responses in combination with dwarf stature and/or spontaneous leaf lesions formation. For most of these mutants, phenotypes are a consequence of an ectopic activation of R genes. Based on the compilation and comparison of published results in this field, we have concluded that the constitutively activated defense phenotypes recurrently arise by disruption of tight, constitutive and multilevel negative control of some of R proteins that might involve also their targeting to the autophagy pathway. This mode of R protein regulation is supported also by protein–protein interactions listed in available databases, as well as in silico search for autophagy machinery interacting motifs. The suggested model could resolve some explanatory discrepancies found in the studies of the immunity responses of autophagy mutants.
- Published
- 2016
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- View/download PDF
5. Exocyst and autophagy-related membrane trafficking in plants.
- Author
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Pečenková, Tamara, Marković, Vedrana, Sabol, Peter, Kulich, Ivan, and Žárský, Viktor
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AUTOPHAGY ,ENDOPLASMIC reticulum ,PROTEIN structure ,ORGANELLES ,AFFERENT pathways ,PROTEOMICS ,MOLECULAR biology ,PHYSIOLOGY - Abstract
Endomembrane traffic in eukaryotic cells functions partially as a means of communication; delivery of membrane in one direction has to be balanced with a reduction at the other end. This effect is typically the case during the defence against pathogens. To combat pathogens, cellular growth and differentiation are suppressed, while endomembrane traffic is poised towards limiting the pathogen attack. The octameric exocyst vesicle-tethering complex was originally discovered as a factor facilitating vesicle-targeting and vesicle-plasma membrane (PM) fusion during exocytosis prior to and possibly during SNARE complex formation. Interestingly, it was recently implicated both in animals and plants in autophagy membrane traffic. In animal cells, the exocyst is integrated into the mTOR-regulated energy metabolism stress/starvation pathway, participating in the formation and especially initiation of an autophagosome. In plants, the first functional link was to autophagy-related anthocyanin import to the vacuole and to starvation. In this concise review, we summarize the current knowledge of exocyst functions in autophagy and defence in plants that might involve unconventional secretion and compare it with animal conditions. Formation of different exocyst complexes during undisturbed cell growth, as opposed to periods of cellular stress reactions involving autophagy, might contribute to the coordination of endomembrane trafficking pathways. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
6. Unconventional Transport Routes of Soluble and Membrane Proteins and Their Role in Developmental Biology.
- Author
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Pompa, Andrea, De Marchis, Francesca, Pallotta, Maria Teresa, Benitez-Alfonso, Yoselin, Jones, Alexandra, Schipper, Kerstin, Moreau, Kevin, Žárský, Viktor, Di Sansebastiano, Gian Pietro, and Bellucci, Michele
- Subjects
MEMBRANE protein genetics ,DEVELOPMENTAL biology ,GOLGI apparatus ,ORGANELLES ,CYTOLOGY - Abstract
Many proteins and cargoes in eukaryotic cells are secreted through the conventional secretory pathway that brings proteins and membranes from the endoplasmic reticulum to the plasma membrane, passing through various cell compartments, and then the extracellular space. The recent identification of an increasing number of leaderless secreted proteins bypassing the Golgi apparatus unveiled the existence of alternative protein secretion pathways. Moreover, other unconventional routes for secretion of soluble or transmembrane proteins with initial endoplasmic reticulum localization were identified. Furthermore, other proteins normally functioning in conventional membrane traffic or in the biogenesis of unique plant/fungi organelles or in plasmodesmata transport seem to be involved in unconventional secretory pathways. These alternative pathways are functionally related to biotic stress and development, and are becoming more and more important in cell biology studies in yeast, mammalian cells and in plants. The city of Lecce hosted specialists working on mammals, plants and microorganisms for the inaugural meeting on “Unconventional Protein and Membrane Traffic” (UPMT) during 4–7 October 2016. The main aim of the meeting was to include the highest number of topics, summarized in this report, related to the unconventional transport routes of protein and membranes. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
7. Autophagy-Related Direct Membrane Import from ER/Cytoplasm into the Vacuole or Apoplast: A Hidden Gateway also for Secondary Metabolites and Phytohormones?
- Author
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Kulich, Ivan and Žárský, Viktor
- Subjects
- *
AUTOPHAGY , *BIOLOGICAL transport , *GOLGI apparatus , *PLANT vacuoles , *PLANT cytoplasm , *PLANT metabolites , *PLANT hormones , *PHYSIOLOGY , *PLANTS - Abstract
Transportation of low molecular weight cargoes into the plant vacuole represents an essential plant cell function. Several lines of evidence indicate that autophagy-related direct endoplasmic reticulum (ER) to vacuole (and also, apoplast) transport plays here a more general role than expected. This route is regulated by autophagy proteins, including recently discovered involvement of the exocyst subcomplex. Traffic from ER into the vacuole bypassing Golgi apparatus (GA) acts not only in stress-related cytoplasm recycling or detoxification, but also in developmentally-regulated biopolymer and secondary metabolite import into the vacuole (or apoplast), exemplified by storage proteins and anthocyanins. We propose that this pathway is relevant also for some phytohormones' (e.g., auxin, abscisic acid (ABA) and salicylic acid (SA)) degradation. We hypothesize that SA is not only an autophagy inducer, but also a cargo for autophagy-related ER to vacuole membrane container delivery and catabolism. ER membrane localized enzymes will potentially enhance the area of biosynthetic reactive surfaces, and also, abundant ER localized membrane importers (e.g., ABC transporters) will internalize specific molecular species into the autophagosome biogenesis domain of ER. Such active ER domains may create tubular invaginations of tonoplast into the vacuoles as import intermediates. Packaging of cargos into the ER-derived autophagosome-like containers might be an important mechanism of vacuole and exosome biogenesis and cytoplasm protection against toxic metabolites. A new perspective on metabolic transformations intimately linked to membrane trafficking in plants is emerging. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
8. Arabidopsis Exocyst Subcomplex Containing Subunit EXO70B1 Is Involved in Autophagy-Related Transport to the Vacuole.
- Author
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Kulich, Ivan, Pečenková, Tamara, Sekereš, Juraj, Smetana, Ondřej, Fendrych, Matyáš, Foissner, Ilse, Höftberger, Margit, and Žárský, Viktor
- Subjects
ARABIDOPSIS ,AUTOPHAGY ,ORIGIN of life ,BIOLOGICAL transport ,ANTHOCYANINS ,SALICYLIC acid ,PLANT physiology ,PLANTS - Abstract
Autophagic transport to the vacuole represents an endomembrane trafficking route, which is widely used in plants, not only during stress situations, but also for vacuole biogenesis and during developmental processes. Here we report a role in autophagic membrane transport for EXO70B1-one of 23 paralogs of Arabidopsis EXO70 exocyst subunits. EXO70B1 positive compartments are internalized into the central vacuole and co-localize with autophagosomal marker ATG8f. This internalization is boosted by induction of autophagy. Loss of function ( LOF) mutations in exo70B1 cause reduction of internalized autopagic bodies in the vacuole. Mutant plants also show ectopic hypersensitive response (HR) mediated by salicylic acid (SA) accumulation, increased nitrogen starvation susceptibility and anthocyanin accumulation defects. Anthocyanin accumulation defect persists in npr1x exo70B1 double mutants with SA signaling compromised, while ectopic HR is suppressed. EXO70B1 interacts with SEC5 and EXO84 and forms an exocyst subcomplex involved in autophagy-related, Golgi-independent membrane traffic to the vacuole. We show that EXO70B1 is functionally completely different from EXO70A1 exocyst subunit and adopted a specific role in autophagic transport. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
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9. Sekrece a autofagie v obraně rostlin proti mikrobům
- Author
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Dobešová, Karolína, Žárský, Viktor, and Burketová, Lenka
- Subjects
microbes ,mikrobi ,autophagy ,autofagie ,sekrece ,secretion ,exocyst ,SNARE ,fungi ,food and beverages - Abstract
Plants are sessile organisms and when attacked by microbes, they cannot easily run away. For this reason, they have developed sophisticated defensive mechanisms, that allow them to defend themselves. Since plants, unlike mammals, do not have any special immune cells, their defense takes place in each cell separately. The key moment during a microbial infection is the recognition of the microbe by the plant through its released molecular patterns (mostly proteins) associated with microbes (MAMPs). MAMPs trigger signaling cascades that lead to the secretion of antimicrobial compounds to the site of an attack. The process of autophagy is also important in the defense against microbes, which not only maintains a cellular homeostasis and controls the level of phytohormones and defense proteins in the plant cytoplasm, but also participates in the secretory activity of the cell. Recent analyzes of plant secretome have shown that plants secrete many proteins (including defensive ones) independently of the signal peptide and compartments of a conventional secretion. During exocytosis a vesicle fuses with the cytoplasmic membrane. The octameric protein complex exocyst and SNARE proteins take part in this process. The exocyst complex is highly diversified in plants - especially it's EXO70 subunit, which is...
- Published
- 2022
10. Funkční specializace paralogů EXO70A a EXO70B podjednotky exocystu EXO70 u Arabidopsis
- Author
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Markovič, Vedrana, Žárský, Viktor, Yalovsky, Shaul, and Ovečka, Miroslav
- Subjects
exocyst ,autophagy ,EXO70 ,exocytosis ,secretion ,food and beverages - Abstract
Many studies in different eukaryotes have shown the importance of the vesicle-tethering exocyst complex for cellular processes dependent on intensive polarized secretion. The plant exocyst complex is crucial for regulation of cell polarity, morphogenesis, and defence. In land plants, gene encoding the EXO70 exocyst subunit multiplied into many paralogs, but only a few of them have been functionally described. In this thesis, the EXO70A2 isoform, a member of the EXO70.1 subfamily, was found to be the main EXO70 exocyst subunit involved in the canonical function of the exocyst complex in Arabidopsis pollen. EXO70A2 is important for several stages of pollen development-pollen grain maturation, germination, and pollen tube growth. Pollen-expressed EXO70A2 was the only EXO70 isoform able to substitute for the function of EXO70A1 in the sporophyte, but not vice-versa. This indicates partial functional redundancy of these two closely related isoforms and a high specificity for pollen-related processes. The finding that the exocyst is targeted to the plasma membrane via EXO70A1 subunit is further elaborated in the thesis. EXO70A1 binds plasma membrane via interactions with specific phospholipids that form a unique plasma membrane-lipid signature in plants. Other isoform, EXO70B1 from the EXO70.2 subfamily,...
- Published
- 2021
11. Unconventional Transport Routes of Soluble and Membrane Proteins and Their Role in Developmental Biology
- Author
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Yoselin Benitez-Alfonso, Francesca De Marchis, Kerstin Schipper, Andrea Pompa, Viktor Žárský, Michele Bellucci, Kevin Moreau, Gian Pietro Di Sansebastiano, Alexandra M. E. Jones, Maria Teresa Pallotta, Pompa, Andrea, De Marchis, Francesca, Pallotta, Maria Teresa, Benitez Alfonso, Yoselin, Jones, Alexandra, Schipper, Kerstin, Moreau, Kevin, Žárský, Viktor, DI SANSEBASTIANO, Gian Pietro, Bellucci, Michele, Maki, M, Moreau, Kevin [0000-0002-3688-3998], and Apollo - University of Cambridge Repository
- Subjects
0301 basic medicine ,membrane proteins ,unconventional secretion ,cell biology ,humans ,Membrane Protein ,Spectroscopy ,protein secretion ,intercellular channels ,exosomes ,autophagy ,trafficking mechanisms ,leaderless proteins ,biology ,Conference Report ,General Medicine ,Endoplasmic reticulum localization ,3. Good health ,Computer Science Applications ,Transport protein ,Cell biology ,animals ,Protein Transport ,Biochemistry ,symbols ,protein transport ,Human ,Autophagy, Exosomes, Intercellular channels, Leaderless proteins, Protein secretion, Trafficking mechanisms, Unconventional secretion ,Catalysis ,intercellular channel ,leaderless protein ,Inorganic Chemistry ,developmental biology ,03 medical and health sciences ,symbols.namesake ,Mitochondrial membrane transport protein ,exosome ,Physical and Theoretical Chemistry ,Molecular Biology ,Secretory pathway ,Animal ,Endoplasmic reticulum ,Organic Chemistry ,Cell Biology ,Golgi apparatus ,trafficking mechanism ,030104 developmental biology ,Secretory protein ,Membrane protein ,biology.protein ,Developmental Biology - Abstract
Many proteins and cargoes in eukaryotic cells are secreted through the conventional secretory pathway that brings proteins and membranes from the endoplasmic reticulum to the plasma membrane, passing through various cell compartments, and then the extracellular space. The recent identification of an increasing number of leaderless secreted proteins bypassing the Golgi apparatus unveiled the existence of alternative protein secretion pathways. Moreover, other unconventional routes for secretion of soluble or transmembrane proteins with initial endoplasmic reticulum localization were identified. Furthermore, other proteins normally functioning in conventional membrane traffic or in the biogenesis of unique plant/fungi organelles or in plasmodesmata transport seem to be involved in unconventional secretory pathways. These alternative pathways are functionally related to biotic stress and development, and are becoming more and more important in cell biology studies in yeast, mammalian cells and in plants. The city of Lecce hosted specialists working on mammals, plants and microorganisms for the inaugural meeting on "Unconventional Protein and Membrane Traffic" (UPMT) during 4-7 October 2016. The main aim of the meeting was to include the highest number of topics, summarized in this report, related to the unconventional transport routes of protein and membranes.
- Published
- 2017
- Full Text
- View/download PDF
12. Study of selected plant exocyst subunits and its interactors in autophagy pathway
- Author
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Rácová, Denisa, Žárský, Viktor, and Wilhelmová, Naďa
- Subjects
exocyst complex ,small GTPases ,komplex exocyst ,autophagy ,autofagie ,dvouhybridní systém v kvasince ,two hybrid system in yeast ,malé GTPázy - Abstract
Exocyst is a binding protein complex, which is evolutionary conserved in yeast, animal and in plant cells. It has crucial role in regulation of cell morfogenesis and cell polarity. The function of the exocyst complex is binding of secretoric vesicle to the proper side on plasma membrane in penultimate step of exocytosis. This process is essecial for function and survival of cell. Another process crucial for the cell is autophagy. In plants autophagy plays important role in the responses to nutrient starvation, senescence, abiotic and biotic stress. RabG3b are small GTPases, which have positive role in autophagy. In this work I described the interaction between RabG3b and some of subunits of exocyst complex: Exo70B1, Exo70B2 and Exo84b. I also studied changes in morfogenesis of tonoplast by induction and inhibition of authophagy and induction of anthocyans synthesis in Arabidopsis thaliana.
- Published
- 2015
13. Conventional and Novel Functions of the Exocyst Complex in Plants
- Author
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Kulich, Ivan, Žárský, Viktor, Baluška, František, and Hašek, Jiří
- Subjects
buněčná polarita ,secretion ,Exo70 ,obrana proti patogenům ,cell polarity ,autofagie ,sekrece ,defence against pathogens ,buněčná stěna ,exocyst ,cell wall ,autophagy - Abstract
Exocyst is an octameric protein complex, conserved across all Eukaryotes. Its role, originally described in yeast, resides in a tethering of the secretory vesicles to the plasma membrane prior to the membrane fusion of the two membranes. Subunits SEC3 and EXO70 are believed to be spatial landmarks for the vesicles delivery. While yeast genome encodes single EXO70, we find dozens of them in land plants (23 in Arabidopsis). This work is focused at a role of the exocyst complex in plant cells. Its first part documents, that exocyst is essential for delivery of the cell wall components, namely pectins, but also for pathogen induced secondary cell wall thickening. Second part reveals an unconventional role of EXO70B1 subunit harboring exocyst subcomplex at an autophagic pathway to the vacuole and raises many questions about plant secretory pathway.
- Published
- 2013
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