ARF is a small, highly basic protein that can be induced by oncogenic stimuli and exerts growth-inhibitory and tumour-suppressive activities through the activation of p53. Here we show that, in human melanocytes, ARF is cytoplasmic, constitutively expressed, and required for maintaining low steady-state levels of superoxide under conditions of mitochondrial dysfunction. This mitochondrial activity of ARF is independent of its known autophagic and p53-dependent functions, and involves the evolutionarily conserved acidic motif GHDDGQ, which exhibits weak homology to BCL-2 homology 3 (BH3) domains and mediates interaction with BCL-xL--an important regulator of mitochondrial redox homeostasis. Melanoma-predisposing CDKN2A germline mutations, which affect conserved glycine and aspartate residues within the GHDDGQ motif, impair the ability of ARF to control superoxide production and suppress growth of melanoma cells in vivo. These results reveal an important cell-protective function of ARF that links mitochondrial dysfunction and susceptibility to melanoma.

• MeSH
• aminokyselinové motivy MeSH
• buněčné dýchání MeSH
• genetická predispozice k nemoci MeSH
• kultivované buňky MeSH
• lidé MeSH
• melanocyty metabolismus   MeSH
• melanom genetika   MeSH
• mitochondriální nemoci metabolismus   MeSH
• nádorový supresorový protein p14ARF metabolismus   MeSH
• protein bcl-X metabolismus   MeSH
• superoxidy metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Cíl práce:Zjistit, které faktory ovlivňují selhání NPPV u pacientů hospitalizovaných na pneumologické JIP pro ARF při exacerbaci CHOPN. Typ studie:Retrospektivní studie. Název a sídlo pracoviště:Klinika nemocí plicních a tuberkulózy, Fakultní nemocnice Brno. Soubor a metody:Retrospektivní studie nemocných hospitalizovaných na pneumologické JIP. Jednalo se o paci- enty, kteří měli akutní respirační insuficienci při akutní exacerbaci CHOPN a byli neinvazivně ventilováni pozitiv- ním přetlakem pomocí obličejové masky. Hodnotili jsme efekt NPPV při přijetí a propuštění z JIP. Dále byli nemoc- ní rozděleni do dvou skupin: úspěšně ventilovaných (S) a těch, u kterých selhala NPPV (F). V těchto skupinách jsme hodnotili tyto parametry: vstupní respirační parametry ( pHa, PaO2, PaCO2,), DF (dechová frekvence), TF (tepová frekvence), věk, komorbidita, APACHE III skóre (1), BMI (body mass index), výška tlakové podpory (Pinsp), PEEP a respirační parametry za 4 hodiny ventilace. Výsledky: Celkem bylo do studie zařazeno 41 pacientů. Ke zlepšení respiračních parametrů došlo u 35 pacientů (86,1 %). Šest pacientů (13,9 %) bylo nutné intubovat a řízeně ventilovat. Zemřeli 4 pacienti (9,8 %) ze skupiny F. Skupina F pacientů, u kterých došlo k selhání NPPV, se významně statisticky nelišila ve věku,vstupních hodnotách pHa, PaO2, PaCO2, DF a zlepšení DF po 4 hodinách ventilace. Skupina F měla vyšší APACHE III, více při- družených onemocnění (p = 0,002) a vyšší vstupní tepovou frekvenci (p = 0,002). Nedošlo u nich ani k signifikantnímu a zlepšení TF a pH po 4 hodinách ventilace. Závěr:Závažná polymorbidita, vysoká hodnota APACHE III, vstupní tepové frekvence a absence ústupu tachykardie a zlepšení pHa po 4 hodinách ventilace dobře predikovaly selhání NPPV.

Objective: Identification of predictive factors of failure of non-invasive positive pressure ventilation (NPPV) in patients admitted to the respiratory ICU with acute respiratory failure (ARF) due to exacerbation of chronic obstructive airway disease (COPD). Design:Retrospective analysis. Setting:Department of Respiratory Diseases and Tuberculosis of University Hospital. Methods:We performed a retrospective analysis of patients admitted to the respiratory ICU with ARF due to acute exacerbation of COPD treated by non-invasive ventilation using a facemask. We evaluated the effect of NPPV during the admission and discharge from the ICU. We divided the patients in two groups: successfully treated (S) vs. patients who needed tracheal intubation, which was considered as treatment failure (F). We studied the following parameters: arterial blood gas on admission (ABG: pHa, PaO2, PaCO2,), respiratory rate (RR), heart rate (HR), age, comorbidity, APACHE III score, BMI, level of ventilatory support (Pinsp) and ABG following 4-hour ventilation. Results: 41 patients were included. Improvement of ABG on NPPV was observed in 35 patients (86.1 %). Endotracheal intubation and mechanical ventilation were necessary in 6 patients (13.9 %). Four patients in group F died (9.8 %). There was no significant difference between groups S and F in age, initial ABG, RR and its improvement after 4 hours of NPPV. Group F patients had a higher APACHE III score, more concomitant diseases (p=0.002) and higher heart rate on admission (P = 0.002). There was no significant improvement in HR and pHa in group F after 4 hours of NPPV. Conclusion: The predictive factors of failure of NPPV were: polymorbidity, high APACHE III score, high HR on admission, and high HR and low pH after 4 hours of ventilation.

• MeSH
• chronická obstrukční plicní nemoc diagnóza   terapie   MeSH
• finanční podpora výzkumu jako téma MeSH
• index tělesné hmotnosti MeSH
• jednotky intenzivní péče MeSH
• komorbidita MeSH
• lidé MeSH
• respirační insuficience diagnóza   terapie   MeSH
• retrospektivní studie MeSH
• věkové faktory MeSH
• ventilace umělá s výdechovým přetlakem kontraindikace   metody   přístrojové vybavení   MeSH
• Check Tag
• lidé MeSH

Giardia intestinalis is an enteric pathogen with an extremely modified membrane trafficking system, lacking canonical compartments such as the Golgi, endosomes, and intermediate vesicle carriers. By comparison the fornicate relatives of Giardia possess greater endomembrane system complexity. In eukaryotes, the ADP ribosylation factor (ARF) GTPase regulatory system proteins, which consist of the small GTPase ARF1, and its guanine exchange nucleotide factors (GEFs) and GTPase activating proteins (GAPs), coordinate temporal and directional trafficking of cargo vesicles by recognizing and interacting with heterotetrameric coat complexes at pre-Golgi and post-Golgi interfaces. To understand the evolution of this regulatory system across the fornicate lineage, we have performed comparative genomic and phylogenetic analyses of the ARF GTPases, and their regulatory GAPs and GEFs in fornicate genomes and transcriptomes. Prior to our analysis of the fornicates, we first establish that the ARF GAP sub-family ArfGAP with dual PH domains (ADAP) is sparsely distributed but present in at least four eukaryotic supergroups and thus was likely present in the Last Eukaryotic Common Ancestor (LECA). Next, our collective comparative genomic and phylogenetic investigations into the ARF regulatory proteins in fornicates identify a duplication of ARF1 GTPase yielding two paralogues of ARF1F proteins, ancestral to all fornicates and present in all examined isolates of Giardia. However, the ARF GEF and ARF GAP complement is reduced compared with the LECA. This investigation shows that the system was significantly streamlined prior to the fornicate ancestor but was not further reduced concurrent with a transition into a parasitic lifestyle.

• MeSH
• ADP-ribosylační faktory * genetika   metabolismus   MeSH
• fylogeneze MeSH
• Giardia lamblia * genetika   metabolismus   MeSH
• proteiny aktivující GTPasu genetika   metabolismus   MeSH
• výměnné faktory guaninnukleotidů genetika   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

• MeSH
• rehabilitace MeSH
• rehabilitační lékařství MeSH
• Publikační typ
• příručky MeSH

• Konspekt
• Fyzioterapie. Psychoterapie. Alternativní lékařství
• NLK Obory
• rehabilitační a fyzikální medicína
• NLK Publikační typ
• kolektivní monografie

BACKGROUND: Processes of anterograde and retrograde membrane trafficking play an important role in cellular homeostasis and dynamic rearrangements of the plasma membrane (PM) in all eukaryotes. These processes depend on the activity of adenosine ribosylation factors (ARFs), a family of GTP-binding proteins and their guanine exchange factors (GEFs). However, knowledge on the function and specificity of individual ARF-GEFs for individual steps of membrane trafficking pathways is still limited in plants. RESULTS: In this work, treatments with various trafficking inhibitors showed that the endocytosis of FM 4-64 is largely dynamin-dependent and relies on proteins containing endocytic tyrosine-based internalization motif and intact cytoskeleton. Interestingly, brefeldin A (BFA), reported previously as an inhibitor of anterograde membrane trafficking in plants, appeared to be the most potent inhibitor of endocytosis in tobacco. In concert with this finding, we demonstrate that the point mutation in the Sec7 domain of the GNOM-LIKE protein1a (NtGNL1a) confers intracellular trafficking pathway-specific BFA resistance. The internalization of FM 4-64 and trafficking of PIN-FORMED1 (PIN1) auxin efflux carrier in BY-2 tobacco cells were studied to reveal the function of the ARF-GEF NtGNL1a in these. CONCLUSIONS: Altogether, our observations uncovered the role of NtGNL1a in endocytosis, including endocytosis of PM proteins (as PIN1 auxin efflux carrier). Moreover these data emphasize the need of careful evaluation of mode of action of non-native inhibitors in various species. In addition, they demonstrate the potential of tobacco BY-2 cells for selective mapping of ARF-GEF-regulated endomembrane trafficking pathways.

• MeSH
• endocytóza MeSH
• kvartérní amoniové sloučeniny metabolismus   MeSH
• pyridinové sloučeniny metabolismus   MeSH
• rostlinné buňky fyziologie   MeSH
• rostlinné proteiny genetika   metabolismus   MeSH
• tabák genetika   fyziologie   MeSH
• transport proteinů MeSH
• výměnné faktory guaninnukleotidů genetika   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

• MeSH
• akutní poškození ledvin diagnóza   etiologie   terapie   MeSH
• dialýza metody   MeSH
• klinické laboratorní techniky statistika a číselné údaje   MeSH
• lidé MeSH
• Check Tag
• lidé MeSH

Abiotic stress poses constant challenges for plant survival and is a serious problem for global agricultural productivity. On a molecular level, stress conditions result in elevation of reactive oxygen species (ROS) production causing oxidative stress associated with oxidation of proteins and nucleic acids as well as impairment of membrane functions. Adaptation of root growth to ROS accumulation is facilitated through modification of auxin and cytokinin hormone homeostasis. Here, we report that in Arabidopsis root meristem, ROS-induced changes of auxin levels correspond to decreased abundance of PIN auxin efflux carriers at the plasma membrane (PM). Specifically, increase in H2O2 levels affects PIN2 endocytic recycling. We show that the PIN2 intracellular trafficking during adaptation to oxidative stress requires the function of the ADP-ribosylation factor (ARF)-guanine-nucleotide exchange factor (GEF) BEN1, an actin-associated regulator of the trafficking from the PM to early endosomes and, presumably, indirectly, trafficking to the vacuoles. We propose that H2O2 levels affect the actin dynamics thus modulating ARF-GEF-dependent trafficking of PIN2. This mechanism provides a way how root growth acclimates to stress and adapts to a changing environment.

• MeSH
• ADP-ribosylační faktory metabolismus   fyziologie   MeSH
• aktiny metabolismus   MeSH
• alkoholoxidoreduktasy metabolismus   fyziologie   MeSH
• Arabidopsis metabolismus   fyziologie   MeSH
• cytoskelet metabolismus   MeSH
• fyziologická adaptace MeSH
• kořeny rostlin metabolismus   fyziologie   MeSH
• oxidační stres * MeSH
• peroxid vodíku metabolismus   MeSH
• proteiny huseníčku metabolismus   fyziologie   MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• výměnné faktory guaninnukleotidů metabolismus   fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH

Membrane traffic at the trans-Golgi network (TGN) is crucial for correctly distributing various membrane proteins to their destination. Polarly localized auxin efflux proteins, including PIN-FORMED1 (PIN1), are dynamically transported between the endosomes and the plasma membrane (PM) in the plant cells. The intracellular trafficking of PIN1 protein is sensitive to the fungal toxin brefeldin A (BFA), which is known to inhibit guanine nucleotide exchange factors for ADP ribosylation factors (ARF GEFs) such as GNOM. However, the molecular details of the BFA-sensitive trafficking pathway have not been fully revealed. In a previous study, we identified an Arabidopsis mutant BFA-visualized endocytic trafficking defective 3 (ben3) which exhibited reduced sensitivity to BFA in terms of BFA-induced intracellular PIN1 agglomeration. Here, we show that BEN3 encodes a member of BIG family ARF GEFs, BIG2. BEN3/BIG2 tagged with fluorescent proteins co-localized with markers for the TGN/early endosome (EE). Inspection of conditionally induced de novo synthesized PIN1 confirmed that its secretion to the PM is BFA sensitive, and established BEN3/BIG2 as a crucial component of this BFA action at the level of the TGN/EE. Furthermore, ben3 mutation alleviated BFA-induced agglomeration of another TGN-localized ARF GEF, BEN1/MIN7. Taken together, our results suggest that BEN3/BIG2 is an ARF GEF component, which confers BFA sensitivity to the TGN/EE in Arabidopsis.

• MeSH
• ADP-ribosylační faktory genetika   metabolismus   MeSH
• alely MeSH
• Arabidopsis účinky léků   metabolismus   MeSH
• brefeldin A farmakologie   MeSH
• buněčná membrána účinky léků   metabolismus   MeSH
• endozomy účinky léků   metabolismus   MeSH
• fenotyp MeSH
• klonování DNA MeSH
• kompartmentace buňky MeSH
• nesmyslný kodon genetika   MeSH
• proteiny huseníčku genetika   metabolismus   MeSH
• semenáček účinky léků   růst a vývoj   MeSH
• trans-Golgiho síť účinky léků   metabolismus   MeSH
• transport proteinů účinky léků   MeSH
• výměnné faktory guaninnukleotidů metabolismus   MeSH
• zelené fluorescenční proteiny metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH

Sensing, integrating, and processing of stressogenic signals must be followed by accurate differential response(s) for a cell to survive and avoid malignant transformation. The DNA damage response (DDR) pathway is vital in this process, as it deals with genotoxic/oncogenic insults, having p53 as a nodal effector that performs most of the above tasks. Accumulating data reveal that other pathways are also involved in the same or similar processes, conveying also to p53. Emerging questions are if, how, and when these additional pathways communicate with the DDR axis. Two such stress response pathways, involving the MKK7 stress-activated protein kinase (SAPK) and ARF, have been shown to be interlocked with the ATM/ATR-regulated DDR axis in a highly ordered manner. This creates a new landscape in the DDR orchestrated response to genotoxic/oncogenic insults that is currently discussed.

• MeSH
• ATM protein metabolismus   MeSH
• čtecí rámce * MeSH
• fosforylace MeSH
• lidé MeSH
• MAP kinasa-kinasa 7 metabolismus   MeSH
• mitogenem aktivované proteinkinasy p38 metabolismus   MeSH
• nádorový supresorový protein p53 metabolismus   MeSH
• onkogeny MeSH
• oprava DNA * MeSH
• poškození DNA * MeSH
• signální transdukce MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH

• MeSH
• akutní poškození ledvin komplikace   terapie   MeSH
• dospělí MeSH
• lidé MeSH
• popálení elektrickým proudem komplikace   terapie   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mužské pohlaví MeSH
• Publikační typ
• kazuistiky MeSH