ALKB-8 is a 2-oxoglutarate-dependent dioxygenase homologous to bacterial AlkB, which oxidatively demethylates DNA substrates. The mammalian AlkB family contains AlkB homologues denominated ALKBH1 to 8 and FTO. The C. elegans genome includes five AlkB-related genes, homologues of ALKBH1, 4, 6, 7, and 8, but lacks homologues of ALKBH2, 3, and 5 and FTO. ALKBH8 orthologues differ from other AlkB family members by possessing an additional methyltransferase module and an RNA binding N-terminal module. The ALKBH8 methyltransferase domain generates the wobble nucleoside 5-methoxycarbonylmethyluridine from its precursor 5-carboxymethyluridine and its (R)- and (S)-5-methoxycarbonylhydroxymethyluridine hydroxylated forms in tRNA Arg/UCG and tRNA Gly/UCC. The ALKBH8/ALKB-8 methyltransferase domain is highly similar to yeast TRM9, which selectively modulates translation of mRNAs enriched with AGA and GAA codons under both normal and stress conditions. In this report, we studied the role of alkb-8 in C. elegans. We show that downregulation of alkb-8 increases detection of lysosome-related organelles visualized by Nile red in vivo. Reversely, forced expression of alkb-8 strongly decreases the detection of this compartment. In addition, overexpression of alkb-8 applied in a pulse during the L1 larval stage increases the C. elegans lifespan.

• MeSH
• Caenorhabditis elegans embryologie   enzymologie   genetika   MeSH
• dioxygenasy metabolismus   MeSH
• dlouhověkost MeSH
• down regulace genetika   MeSH
• embryo nesavčí metabolismus   MeSH
• geneticky modifikovaná zvířata MeSH
• kyseliny ketoglutarové metabolismus   MeSH
• larva metabolismus   MeSH
• lyzozomy metabolismus   MeSH
• methyltransferasy metabolismus   MeSH
• operon MeSH
• promotorové oblasti (genetika) MeSH
• proteiny Caenorhabditis elegans genetika   metabolismus   MeSH
• RNA interference MeSH
• S-adenosylmethionin metabolismus   MeSH
• stárnutí metabolismus   MeSH
• vývojová regulace genové exprese MeSH
• zelené fluorescenční proteiny metabolismus   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Intracellular accumulation of misfolded proteins causes toxic proteinopathies, diseases without targeted therapies. Mucin 1 kidney disease (MKD) results from a frameshift mutation in the MUC1 gene (MUC1-fs). Here, we show that MKD is a toxic proteinopathy. Intracellular MUC1-fs accumulation activated the ATF6 unfolded protein response (UPR) branch. We identified BRD4780, a small molecule that clears MUC1-fs from patient cells, from kidneys of knockin mice and from patient kidney organoids. MUC1-fs is trapped in TMED9 cargo receptor-containing vesicles of the early secretory pathway. BRD4780 binds TMED9, releases MUC1-fs, and re-routes it for lysosomal degradation, an effect phenocopied by TMED9 deletion. Our findings reveal BRD4780 as a promising lead for the treatment of MKD and other toxic proteinopathies. Generally, we elucidate a novel mechanism for the entrapment of misfolded proteins by cargo receptors and a strategy for their release and anterograde trafficking to the lysosome.

• MeSH
• benzamidy chemie   metabolismus   farmakologie   MeSH
• epitelové buňky cytologie   metabolismus   MeSH
• imidazolinové receptory antagonisté a inhibitory   genetika   metabolismus   MeSH
• indukované pluripotentní kmenové buňky cytologie   metabolismus   MeSH
• ledviny cytologie   metabolismus   patologie   MeSH
• lidé MeSH
• lyzozomy metabolismus   MeSH
• malá interferující RNA metabolismus   MeSH
• mucin 1 chemie   genetika   metabolismus   MeSH
• myši transgenní MeSH
• myši MeSH
• nemoci ledvin metabolismus   patologie   MeSH
• posunová mutace MeSH
• RNA interference MeSH
• signální dráha UPR účinky léků   MeSH
• transkripční faktor ATF6 metabolismus   MeSH
• vezikulární transportní proteiny chemie   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

To examine reciprocal or unilateral implications between two cell destruction processes, autophagy and apoptosis, in 5-Fluorouracil (5-FU)-treated tumor cells, a combination of chemical inhibitors, RNAi and genetic approaches were used. In contrast to cancer cells harboring obstructed apoptosis, either at the DISC or the mitochondrial level, p53-deficiency generated signs of autophagy deregulation upon chemotherapy. On the other, hand disruption of lysosomal function by chloroquine, caused a profound decrease in apoptotic markers appearing in response to 5-FU. DR5, which is essential for 5-FU-induced apoptosis, accumulated in lysosomes and autophagosomes upon chloroquine treatment. Since neither 3-MA, RNAi of critical autophagy regulators or inhibition of cathepsins reversed apoptosis in a similar manner, it is likely that not autophagy per se but rather correct receptor transport is an important factor for 5-FU cytotoxicity. We found that apoptosis generated by TRAIL, the cognate ligand for DR5, remained unchanged upon chloroquine lysosomal interference, indicating that 5-FU activates the receptor by a discrete mechanism. In support, depletion of membrane cholesterol or hampering cholesterol transport drastically reduced 5-FU cytotoxicity. We conclude that targeting of lysosomes by chloroquine deregulates DR5 trafficking and abrogates 5-FU- but not TRAIL-stimulated cell elimination, hence suggesting a novel mechanism for receptor activation.

• MeSH
• antimetabolity antitumorózní farmakologie   MeSH
• apoptóza MeSH
• autofagie * MeSH
• buněčná membrána metabolismus   MeSH
• chlorochin chemie   MeSH
• cholesterol chemie   MeSH
• fagozomy MeSH
• fluorouracil chemie   MeSH
• HCT116 buňky MeSH
• lidé MeSH
• ligandy MeSH
• lyzozomy metabolismus   MeSH
• makrolidy chemie   MeSH
• mitochondrie metabolismus   MeSH
• nádorový supresorový protein p53 metabolismus   MeSH
• protein TRAIL farmakologie   MeSH
• RNA interference MeSH
• signální transdukce účinky léků   MeSH
• TRAIL receptory metabolismus   MeSH
• transport proteinů MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Intracellular proteolysis of ingested blood proteins is a crucial physiological process in ticks. In our model tick, Ixodes ricinus, cathepsin L (IrCL1) is part of a gut-associated multi-peptidase complex; its endopeptidase activity is important in the initial phase of haemoglobinolysis. We present the functional and biochemical characterisation of this enzyme. We show, by RNA interference (RNAi), that cathepsin L-like activity that peaks during the slow feeding period of females is associated with IrCL1. Recombinant IrCL1 was expressed in bacteria and yeast. Activity profiling with both peptidyl and physiological protein substrates (haemoglobin and albumin) revealed that IrCL1 is an acidic peptidase with a very low optimum pH (3-4) being unstable above pH 5. This suggests an endo/lysosomal localisation that was confirmed by indirect fluorescence microscopy that immunolocalised IrCL1 inside the vesicles of digestive gut cells. Cleavage specificity determined by a positional scanning synthetic combinatorial library and inhibition profile indicated that IrCL1 has the ligand-binding characteristics of the cathepsin L subfamily of cysteine peptidases. A non-redundant proteolytic function was demonstrated when IrCL1-silenced ticks had a decreased ability to feed compared with controls. The data suggest that IrCL1 may be a promising target against ticks and tick-borne pathogens.

• MeSH
• albuminy metabolismus   MeSH
• endozomy enzymologie   MeSH
• exprese genu MeSH
• fluorescenční mikroskopie MeSH
• hemoglobiny metabolismus   MeSH
• kathepsin L chemie   genetika   metabolismus   MeSH
• klíště enzymologie   MeSH
• koncentrace vodíkových iontů MeSH
• proteolýza MeSH
• rekombinantní proteiny chemie   genetika   metabolismus   MeSH
• RNA interference MeSH
• stabilita enzymů MeSH
• umlčování genů MeSH
• zvířata MeSH
• Check Tag
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The delivery of newly synthesized soluble lysosomal hydrolases to the endosomal system is essential for lysosome function and cell homeostasis. This process relies on the proper trafficking of the mannose 6-phosphate receptors (MPRs) between the trans-Golgi network (TGN), endosomes and the plasma membrane. Many transmembrane proteins regulating diverse biological processes ranging from virus production to the development of multicellular organisms also use these pathways. To explore how cell signaling modulates MPR trafficking, we used high-throughput RNA interference (RNAi) to target the human kinome and phosphatome. Using high-content image analysis, we identified 127 kinases and phosphatases belonging to different signaling networks that regulate MPR trafficking and/or the dynamic states of the subcellular compartments encountered by the MPRs. Our analysis maps the MPR trafficking pathways based on enzymes regulating phosphatidylinositol phosphate metabolism. Furthermore, it reveals how cell signaling controls the biogenesis of post-Golgi tubular carriers destined to enter the endosomal system through a SRC-dependent pathway regulating ARF1 and RAC1 signaling and myosin II activity.

• MeSH
• ADP-ribosylační faktor 1 genetika   metabolismus   MeSH
• buněčná membrána enzymologie   MeSH
• endozomy enzymologie   MeSH
• fosfatidylinositolfosfáty metabolismus   MeSH
• genové regulační sítě MeSH
• HeLa buňky MeSH
• lidé MeSH
• mapy interakcí proteinů MeSH
• rac1 protein vázající GTP genetika   metabolismus   MeSH
• receptor IGF typ 2 genetika   metabolismus   MeSH
• regulace genové exprese enzymů MeSH
• RNA interference * MeSH
• shluková analýza MeSH
• signální transdukce MeSH
• skupina kinas odvozených od src-genu genetika   metabolismus   MeSH
• trans-Golgiho síť enzymologie   MeSH
• transfekce MeSH
• transport proteinů genetika   MeSH
• vysoce účinné nukleotidové sekvenování metody   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• audiovizuální média MeSH
• časopisecké články MeSH
• práce podpořená grantem MeSH

Cathepsin D (CD), a ubiquitously expressed lysosomal aspartic protease, is upregulated in human breast carcinoma and many other tumor types. CD has been repeatedly reported to act as key mediator of apoptosis induced by various chemotherapeutics. However, there is still controversy over the role of enzymatic/proteolytic versus protein-protein interaction activities of CD in apoptotic signaling. The elucidation of molecular mechanism responsible for the effect of CD in the chemotherapy-induced cell death is crucial for development of an appropriate strategy to target this protease in cancer treatment. Therefore, the objective of this study was to investigate the molecular mechanism behind the CD-mediated regulation of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced cell death. For this purpose, MDA-MB-231 breast carcinoma cells with an increased level of wt CD (CD) or mutant enzymatically inactive CD (ΔCD) were subjected to TRAIL and the frequency of apoptosis was determined. Our results show that CD facilitates the TRAIL-induced apoptosis of MDA-MB-231 breast cancer cells in enzymatic activity-dependent manner. Moreover, the importance of endosomal/lysosomal acidification in this process was documented. Analysis of the potential substrates specifically cleaved by CD during the TRAIL-induced apoptosis confirmed caspase-8 and Bid proteins as the CD targets. Moreover, in search for protein regulators of apoptosis that can be cleaved by CD at physiologically relevant pH, we identified the Bcl-2 protein as a suitable candidate. The modulatory role of CD in cell response to TRAIL was also confirmed in another breast cancer cell line SKBR3. These experiments identified the CD enzymatic activity as a new factor affecting sensitivity of breast cancer cells to TRAIL.

• MeSH
• adenokarcinom enzymologie   patologie   MeSH
• aktivace enzymů MeSH
• apoptóza účinky léků   MeSH
• chemorezistence MeSH
• endozomy metabolismus   MeSH
• kaspasa 8 metabolismus   MeSH
• kathepsin D antagonisté a inhibitory   genetika   fyziologie   MeSH
• koncentrace vodíkových iontů MeSH
• lidé MeSH
• lyzozomy metabolismus   MeSH
• malá interferující RNA genetika   MeSH
• nádorové buněčné linie MeSH
• nádorové proteiny antagonisté a inhibitory   genetika   fyziologie   MeSH
• nádory prsu enzymologie   patologie   MeSH
• protein Bid metabolismus   MeSH
• protein TRAIL farmakologie   MeSH
• protoonkogenní proteiny c-bcl-2 metabolismus   MeSH
• rekombinantní proteiny metabolismus   farmakologie   MeSH
• RNA interference MeSH
• transfekce MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

To ensure successful feeding tick saliva contains a number of inhibitory proteins that interfere with the host immune response and help to create a permissive environment for pathogen transmission. Among the potential targets of the salivary cystatins are two host cysteine proteases, cathepsin S, which is essential for antigen- and invariant chain-processing, and cathepsin C (dipeptidyl peptidase 1, DPP1), which plays a critical role in processing and activation of the granule serine proteases. Here, the effect of salivary cystatin OmC2 fromOrnithodoros moubatawas studied using differentiated MUTZ-3 cells as a model of immature dendritic cells of the host skin. Following internalization, cystatin OmC2 was initially found to inhibit the activity of several cysteine cathepsins, as indicated by the decreased rates of degradation of fluorogenic peptide substrates. To identify targets, affinity chromatography was used to isolate His-tagged cystatin OmC2 together with the bound proteins from MUTZ-3 cells. Cathepsins S and C were identified in these complexes by mass spectrometry and confirmed by immunoblotting. Furthermore, reduced increase in the surface expression of MHC II and CD86, which are associated with the maturation of dendritic cells, was observed. In contrast, human inhibitor cystatin C, which is normally expressed and secreted by dendritic cells, did not affect the expression of CD86. It is proposed that internalization of salivary cystatin OmC2 by the host dendritic cells targets cathepsins S and C, thereby affecting their maturation.

• MeSH
• antigeny CD86 MeSH
• antigeny diferenciační B-lymfocytární MeSH
• buněčné linie MeSH
• cystatiny metabolismus   MeSH
• dendritické buňky imunologie   metabolismus   MeSH
• epoxidové sloučeniny imunologie   metabolismus   MeSH
• geny MHC třídy II imunologie   MeSH
• histokompatibilita - antigeny třídy II MeSH
• kathepsin C metabolismus   MeSH
• kathepsiny chemie   imunologie   metabolismus   MeSH
• klíšťata enzymologie   MeSH
• lidé MeSH
• lyzozomy enzymologie   MeSH
• Ornithodoros enzymologie   MeSH
• rekombinantní proteiny MeSH
• sliny enzymologie   MeSH
• tyrosin analogy a deriváty   imunologie   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The toxic modes of action of non-dioxin-like polychlorinated biphenyls (PCBs) in liver cells are still only partially understood. Several recent studies have indicated that PCBs may interfere with cell membrane protein functions. Therefore, we analyzed in the present study the effects of di-ortho-substituted 2,2',4,4',5,5'-hexachlorobiphenyl (PCB 153) on proteins involved in the formation of adherens junctions in a model of rat liver progenitor cells - WB-F344 cell line. PCB 153, at micromolar concentrations, induced a gradual degradation of E-cadherin, beta-catenin or plakoglobin (gamma-catenin) proteins. This effect was not due to changes in gene expression, as PCB 153 had no effect on mRNA levels of the above mentioned proteins. Moreover, apart from the reduction of total beta-catenin pool, PCB 153 also decreased levels of the active beta-catenin form, dephosphorylated at residues Ser37 and Thr41, which is the key co-activator of Wnt-induced TCF/LEF-dependent gene expression. Therefore, we also evaluated the impact of PCB 153 on expression of Axin2, a known transcriptional target of canonical Wnt signaling. PCB 153 reduced basal Axin2 mRNA levels and it inhibited induction of Axin2 expression by recombinant mouse Wnt3a. Nevertheless, PCB 153 had no effect on phosphorylation of glycogen synthase kinase-3beta (GSK-3beta), which is supposed to target beta-catenin for its proteasomal degradation. This suggested that GSK-3beta activity is not modulated by PCB 153 and, consequently, not involved in the observed PCB 153-induced decrease of both total and active beta-catenin levels. Protein levels of E-cadherin and beta-catenin were partially restored with lysosomal inhibitor leupeptin, thus suggesting a possible role of lysosomes in the observed degradation of adherens junction proteins. Taken together, the present data suggest that PCB 153 may interfere with functions of adherens junction proteins involved in both cell-to-cell communication and intracellular signaling. Such mechanisms might be involved in the effects of non-dioxin-like PCBs contributing to liver tumor promotion.

• MeSH
• adhezní spoje metabolismus   účinky léků   MeSH
• beta-katenin antagonisté a inhibitory   biosyntéza   genetika   MeSH
• buněčné linie MeSH
• epitelové buňky cytologie   metabolismus   účinky léků   MeSH
• fosforylace účinky léků   MeSH
• gama-katenin biosyntéza   genetika   metabolismus   MeSH
• genetická transkripce účinky léků   MeSH
• inhibitory cysteinových proteinas farmakologie   MeSH
• játra cytologie   metabolismus   účinky léků   MeSH
• kadheriny biosyntéza   genetika   metabolismus   MeSH
• kinasa 3 glykogensynthasy metabolismus   MeSH
• kmenové buňky cytologie   metabolismus   účinky léků   MeSH
• krysa rodu rattus MeSH
• leupeptiny farmakologie   MeSH
• lyzozomy metabolismus   MeSH
• messenger RNA biosyntéza   genetika   MeSH
• polychlorované bifenyly toxicita   MeSH
• polymerázová řetězová reakce s reverzní transkripcí MeSH
• represorové proteiny biosyntéza   genetika   metabolismus   MeSH
• western blotting MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• zvířata MeSH
• Publikační typ
• práce podpořená grantem MeSH

Aggregation of the high-affinity receptor for IgE (FcεRI) in mast cells initiates activation events that lead to degranulation and release of inflammatory mediators. To better understand the signaling pathways and genes involved in mast cell activation, we developed a high-throughput mast cell degranulation assay suitable for RNA interference experiments using lentivirus-based short hairpin RNA (shRNA) delivery. We tested 432 shRNAs specific for 144 selected genes for effects on FcεRI-mediated mast cell degranulation and identified 15 potential regulators. In further studies, we focused on galectin-3 (Gal3), identified in this study as a negative regulator of mast cell degranulation. FcεRI-activated cells with Gal3 knockdown exhibited upregulated tyrosine phosphorylation of spleen tyrosine kinase and several other signal transduction molecules and enhanced calcium response. We show that Gal3 promotes internalization of IgE-FcεRI complexes; this may be related to our finding that Gal3 is a positive regulator of FcεRI ubiquitination. Furthermore, we found that Gal3 facilitates mast cell adhesion and motility on fibronectin but negatively regulates antigen-induced chemotaxis. The combined data indicate that Gal3 is involved in both positive and negative regulation of FcεRI-mediated signaling events in mast cells.

• MeSH
• aktiny metabolismus   MeSH
• buněčná adheze MeSH
• chemotaxe MeSH
• cytokiny genetika   metabolismus   MeSH
• fosforylace MeSH
• galektin 3 genetika   metabolismus   MeSH
• lyzozomy metabolismus   MeSH
• malá interferující RNA MeSH
• mastocyty cytologie   fyziologie   MeSH
• myši inbrední BALB C MeSH
• prostaglandin D2 metabolismus   MeSH
• receptory IgE genetika   metabolismus   MeSH
• signální transdukce MeSH
• ubikvitinace MeSH
• vápník metabolismus   MeSH
• vysoce účinné nukleotidové sekvenování MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

Drug-induced ion channel trafficking disturbance can cause cardiac arrhythmias. The subcellular level at which drugs interfere in trafficking pathways is largely unknown. KIR 2.1 inward rectifier channels, largely responsible for the cardiac inward rectifier current (IK1 ), are degraded in lysosomes. Amiodarone and dronedarone are class III antiarrhythmics. Chronic use of amiodarone, and to a lesser extent dronedarone, causes serious adverse effects to several organs and tissue types, including the heart. Both drugs have been described to interfere in the late-endosome/lysosome system. Here we defined the potential interference in KIR 2.1 backward trafficking by amiodarone and dronedarone. Both drugs inhibited IK1 in isolated rabbit ventricular cardiomyocytes at supraclinical doses only. In HK-KWGF cells, both drugs dose- and time-dependently increased KIR 2.1 expression (2.0 ± 0.2-fold with amiodarone: 10 μM, 24 hrs; 2.3 ± 0.3-fold with dronedarone: 5 μM, 24 hrs) and late-endosomal/lysosomal KIR 2.1 accumulation. Increased KIR 2.1 expression level was also observed in the presence of Nav 1.5 co-expression. Augmented KIR 2.1 protein levels and intracellular accumulation were also observed in COS-7, END-2, MES-1 and EPI-7 cells. Both drugs had no effect on Kv 11.1 ion channel protein expression levels. Finally, amiodarone (73.3 ± 10.3% P < 0.05 at -120 mV, 5 μM) enhanced IKIR2.1 upon 24-hrs treatment, whereas dronedarone tended to increase IKIR2.1 and it did not reach significance (43.8 ± 5.5%, P = 0.26 at -120 mV; 2 μM). We conclude that chronic amiodarone, and potentially also dronedarone, treatment can result in enhanced IK1 by inhibiting KIR 2.1 degradation.

• MeSH
• amiodaron analogy a deriváty   farmakologie   MeSH
• antiarytmika farmakologie   MeSH
• Cercopithecus aethiops MeSH
• COS buňky MeSH
• draslíkové kanály dovnitř usměrňující genetika   fyziologie   MeSH
• gating iontového kanálu účinky léků   genetika   fyziologie   MeSH
• HEK293 buňky MeSH
• kardiomyocyty cytologie   účinky léků   fyziologie   MeSH
• králíci MeSH
• kultivované buňky MeSH
• lidé MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• zvířata MeSH
• Check Tag
• králíci MeSH
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH