Search results for "RAB18"

showing 5 items of 5 documents

On-demand autophagic network adaptations upon limited lipid availability

2020

The de novo synthesis of autophagic vesicles is strongly dependent on sufficient lipid supply. Recently, the RAB GTPase RAB18 was shown to affect autophagy by mediating fatty acid release from lipid droplets, which are lipid sources for autophagosome formation. The stable loss of RAB18 interfered with fatty acid release from the lipid reservoirs and provoked autophagy network adaptations aiming to maintain autophagic activity under lipid limiting conditions.

0301 basic medicineAutophagy-Related ProteinsGTPaseBiologyModels Biological03 medical and health sciencesLipid dropletAutophagyHumansMolecular Biologychemistry.chemical_classification030102 biochemistry & molecular biologyVesicleAutophagyFatty acidLipid DropletsCell BiologyAdaptation PhysiologicalLipidsCell biologyDe novo synthesis030104 developmental biologychemistryrab GTP-Binding Proteinslipids (amino acids peptides and proteins)RabCommentary and ViewsRAB18Autophagy
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Enhanced autophagic-lysosomal activity and increased BAG3-mediated selective macroautophagy as adaptive response of neuronal cells to chronic oxidati…

2019

Oxidative stress and a disturbed cellular protein homeostasis (proteostasis) belong to the most important hallmarks of aging and of neurodegenerative disorders. The proteasomal and autophagic-lysosomal degradation pathways are key measures to maintain proteostasis. Here, we report that hippocampal cells selected for full adaptation and resistance to oxidative stress induced by hydrogen peroxide (oxidative stress-resistant cells, OxSR cells) showed a massive increase in the expression of components of the cellular autophagic-lysosomal network and a significantly higher overall autophagic activity. A comparative expression analysis revealed that distinct key regulators of autophagy are upregu…

0301 basic medicineClinical BiochemistryLFQ Label-free quantificationLETM Leucine zipper and EF-hand containing transmembrane proteinmedicine.disease_causeBiochemistryCHX Cycloheximide0302 clinical medicineBNIP3 Bcl-2 interacting protein 3RAPA RapamycinPIK3C3 Class III PI3‐kinasePhosphorylationlcsh:QH301-705.5Neuronslcsh:R5-920PolyUB PolyubiquitinChemistryBAG3OPA1 Optic atrophy 1TOR Serine-Threonine KinasesWIPI1 WD repeat domain phosphoinositide-interacting protein 1ATG Autophagy relatedTFEB Transcription factor EBCell biologyMitochondriasiRNA Small interfering RNADLP1 Dynamin-like protein 1LAMP1 Lysosomal‐associated membrane protein 1PURO Puromycinlcsh:Medicine (General)Protein homeostasisResearch PaperBafA1 Bafilomycin A1LAMP2 Lysosomal‐associated membrane protein 2Proteasome Endopeptidase ComplexRAB18 Member RAS oncogeneTUB TubulinLC3 Light chain 3 proteinOxidative phosphorylationBAG3CTSD Cathepsin DModels BiologicalCell Line03 medical and health sciencesDownregulation and upregulationMacroautophagymedicineAutophagyHumansAdaptationBAG1 Bcl-2-associated athanogene 1BECN1 Beclin1PI3K/AKT/mTOR pathwayAdaptor Proteins Signal TransducingTEM Transmission electron microscopyHsp70 Heat shock protein 70Organic ChemistryAutophagyAutophagosomesmTOR Mammalian target of rapamycinHsp70Oxidative Stress030104 developmental biologyProteostasislcsh:Biology (General)CV CanavanineBAG3 Bcl-2-associated athanogene 3MTT (3-(45-Dimethylthiazol-2-yl)-25-Diphenyltetrazolium Bromide)Apoptosis Regulatory ProteinsLysosomes030217 neurology & neurosurgeryOxidative stressRedox Biology
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The RAB GTPase RAB18 modulates macroautophagy and proteostasis

2017

Macroautophagy is a conserved degradative pathway and its deterioration is linked to disturbances in cellular proteostasis and multiple diseases. Here, we show that the RAB GTPase RAB18 modulates autophagy in primary human fibroblasts. The knockdown of RAB18 results in a decreased autophagic activity, while its overexpression enhances the degradative pathway. Importantly, this function of RAB18 is dependent on RAB3GAP1 and RAB3GAP2, which might act as RAB GEFs and stimulate the activity of the RAB GTPase. Moreover, the knockdown of RAB18 deteriorates proteostasis and results in the intracellular accumulation of ubiquitinated degradation-prone proteins. Thus, the RAB GTPase RAB18 is a positi…

0301 basic medicineRecombinant Fusion Proteinsrab3 GTP-Binding ProteinsPrimary Cell CultureBiophysicsGTPaseBiochemistry03 medical and health sciencesUbiquitinGenes ReporterAutophagyHumansRNA Small InterferingMolecular BiologyGene knockdownbiologyProtein StabilityChemistryfungiAutophagyCell BiologyFibroblastsCell biologyLuminescent Proteins030104 developmental biologyProteostasisGene Expression Regulationrab GTP-Binding ProteinsProteolysisbiology.proteinCancer researchRabSignal transductionRAB18Signal TransductionBiochemical and Biophysical Research Communications
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RAB18 impacts autophagy via lipid droplet-derived lipid transfer and is rescued by ATG9A

2018

AbstractAutophagy is a lysosomal degradation pathway that mediates protein and organelle turnover and maintains cellular homeostasis. Autophagosomes transport cargo to lysosomes and their formation is dependent on an appropriate lipid supply. Here, we show that the knockout of the RAB GTPase RAB18 interferes with lipid droplet (LD) metabolism, resulting in an impaired fatty acid mobilization. The reduced LD-derived lipid availability influences autophagy and provokes adaptive modifications of the autophagy network, which include increased ATG2B expression and ATG12-ATG5 conjugate formation as well as enhanced ATG2B and ATG9A phosphorylation. Phosphorylation of ATG9A directs this transmembra…

ChemistryLipid dropletAutophagyOrganellePhosphorylationCellular homeostasisGTPaseRabRAB18Cell biology
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RAB18 Loss Interferes With Lipid Droplet Catabolism and Provokes Autophagy Network Adaptations

2020

Autophagy is dependent on appropriate lipid supply for autophagosome formation. The regulation of lipid acquisition and the autophagy network response to lipid-limiting conditions are mostly elusive. Here, we show that the knockout of the RAB GTPase RAB18 interferes with lipid droplet catabolism, causing an impaired fatty acid release. The resulting reduced lipid-droplet-derived lipid availability influences autophagy and provokes adaptive modifications of the autophagy network. These adjustments include increased expression and phosphorylation of ATG2B as well as augmented formation of the ATG12-ATG5 conjugate. Moreover, ATG9A shows an enhanced phosphorylation at amino acid residues tyrosi…

rab3 GTP-Binding ProteinsImmunoblottingGTPaseReal-Time Polymerase Chain Reaction03 medical and health sciences0302 clinical medicineMicroscopy Electron TransmissionStructural BiologyLipid dropletAutophagyHumansPhosphorylationTyrosineMolecular Biology030304 developmental biology0303 health sciencesMicroscopy ConfocalChemistryCatabolismAutophagyAutophagosomesLipid DropletsImmunohistochemistryCell biologyrab GTP-Binding ProteinsPhosphorylationlipids (amino acids peptides and proteins)RabCRISPR-Cas Systems030217 neurology & neurosurgeryRAB18HeLa CellsJournal of Molecular Biology
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