Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Molecular determinants of the crosstalk between endosomal microautophagy and chaperone-mediated autophagy

ABSTRACT: Chaperone-mediated autophagy (CMA) and endosomal microautophagy (eMI) are pathways for selective degradation of cytosolic proteins in endo-lysosomal compartments. These autophagic processes share as a first step the recognition of the same five amino acid motif in substrate proteins by the hsc70 chaperone, therefore raising the possibility of a regulatory network linking the two pathways. In this work, we demonstrate the existence of a compensatory relationship between CMA and eMI and identify a role for the chaperone protein Bag6 in triage and internalization of eMI substrates into the late endosome. Association and dynamics of Bag6 at the late endosome membrane change during starvation which we found that, contrary to other autophagic pathways, causes a decline in eMI activity. Collectively, we establish a coordinated function of eMI with CMA, identify the interchangeable subproteome degraded by these pathways and start to elucidate the molecular mechanisms that facilitate the switch between them.

INSTRUMENT(S): timsTOF Pro

ORGANISM(S): Mus Musculus (mouse)

TISSUE(S): Liver

SUBMITTER: Danielle Swaney

LAB HEAD: Nevan Krogan

PROVIDER: PXD029580 | Pride | 2023-10-30

REPOSITORIES: Pride

ACCESS DATA

Json Xml

Similar Datasets

Identification of the late endosome LE/MVB proteome related to the endosomal microautophagy eMI activity in the rat liver.

Project description:To identify the late endosome LE/MVB proteome related to the endosomal microautophagy eMI activity we purified subcellular organelles including cytosol, late endosomes (LE/MVBs) and lysosomes (CMA+) from the rat liver and performed co-Ip experiment with antibodies directed against the major cellular chaperones mediating CMA and eMI. As such, we analyzed Hsc70-interacting proteins in LE/MVB, CMA+ lysosomes and cytosol by performing pull-down experiments (co-IP) using anti-Hsc70 antibodies. A comparative analysis of the Hsc-70 interactomes revealed that proteins bound to Hsc70 in cytosol and LE/MVBs or in cytosol and CMA+ lysosomes were considered eMI or CMA substrates, respectively.

2024-01-26 | PXD046797 | Pride

SILAC-based quantitative proteomics using mass spectrometry identifies BAG-6 mediated changes in the subproteome degraded by endosomal microautophagy (eMI).

Project description:To identify the subproteome degraded by endosomal microautophagy (eMI) in a Bag6-dependent manner, we compared the proteome of late endosomal compartments LE/MVBs isolated from control(wild type) and Bag6(-) cells using SILAC labeling and quantitative proteomics.

2024-01-26 | PXD046760 | Pride

Reduced endosomal microautophagy activity in aging associates with enhanced exocyst-mediated protein secretion

Project description:Autophagy is essential for protein quality control and regulation of the functional proteome. Failure of autophagy pathways with age contributes to loss of proteostasis in aged organisms and accelerates progression of age-related diseases. In this work, we show that activity of endosomal microautophagy (eMI), a selective type of autophagy occurring in late endosomes, declines with age and identify the subproteome affected by this loss of function. Proteomics of late endosomes from old mice revealed an aberrant glycation signature for hsc70, the chaperone responsible for substrate targeting to eMI. Age-related hsc70 glycation reduces its stability in late endosomes by favoring its organization into high molecular weight protein complexes and promoting its internalization/degradation inside late endosomes. Reduction of eMI with age associates with an increase in protein secretion, as late endosomes can release protein-loaded exosomes upon plasma membrane fusion. Our search for molecular mediators of the eMI/secretion switch identified the exocyst-RalA complex, known for its role in exocytosis, as a novel physiological eMI inhibitor that interacts with hsc70 and acts directly at the late endosome membrane. This inhibitory function along with the higher exocyst-RalA complex levels detected in late endosomes from old mice could explain, at least in part, reduced eMI activity with age. Interaction of hsc70 with components of the exocyst-RalA complex places this chaperone in the switch from eMI to secretion. Reduced intracellular degradation in favor of extracellular release of undegraded material with age may be relevant to the spreading of proteotoxicity associated with aging and progression of proteinopathies.

2023-03-11 | PXD035128 | Pride

Transcriptome analysis of vascular smooth muscle cells from mice deficient for chaperone-mediated autophagy

Project description:Chaperone-mediated autophagy (CMA) contributes to regulation of energy homeostasis by timely degradation of enzymes involved in glucose and lipid metabolism. Here, we report reduced CMA activity in vascular smooth muscle cells and macrophages in murine and human arteries in response to atherosclerotic challenges. We show that in vivo genetic blockage of CMA worsens atherosclerotic pathology through both systemic and cell-autonomous changes in vascular smooth muscle cells and macrophages, the two main cell types involved in atherogenesis. CMA deficiency promotes dedifferentiation of vascular smooth muscle cells and a pro-inflammatory state in macrophages. Conversely, a genetic mouse model with upregulated CMA shows lower vulnerability to the pro-atherosclerotic challenge. We propose that CMA could be an attractive therapeutic target against cardiovascular diseases.

2022-03-14 | GSE143162 | GEO

Trancriptome analysis in mice deficient for chaperone-mediated autophagy in liver

Project description:The activity of chaperone-mediated autophagy (CMA), a catabolic pathway for selective degradation of cytosolic proteins in lysosomes, decreases with age, but the consequences of this functional decline in vivo remain unknown. In this work, we have generated a conditional knockout mouse to selectively block CMA in liver. We have found that blockage of CMA causes hepatic glycogen depletion and hepatosteatosis. The liver phenotype is accompanied by reduced peripheral adiposity, increased energy expenditure, and altered glucose homeostasis. Comparative lysosomal proteomics revealed that key enzymes in carbohydrate and lipid metabolism are normally degraded by CMA and that impairment of this regulated degradation contributes to the metabolic abnormalities observed in CMA-defective animals. These findings highlight the involvement of CMA in regulating hepatic metabolism and suggest that the age-related decline in CMA may have a negative impact on the energetic balance of old organisms.

2014-12-31 | GSE49553 | GEO

Mutant glucocerebrosidase impairs alpha-synuclein degradation by blockade of chaperone-mediated autophagy

Project description:The most common genetic risk factors for Parkinson’s disease (PD) are a set of heterozygous mutant (MT) alleles of the GBA1 gene that encodes Beta-glucocerebrosidase (GCase), an enzyme normally trafficked through the ER/ Golgi apparatus to the lysosomal lumen. We found that half of the GCase in lysosomes from post-mortem human GBA-PD brains was present on the lysosomal surface, and that this mislocalization depends on a pentapeptide motif in GCase used to target cytosolic protein for degradation by chaperone-mediated autophagy (CMA). Unfolded mutant GCase at the lysosomal surface inhibits CMA, causing accumulation of CMA substrates including -synuclein. Using single cell transcriptional analysis and comparative proteomics of brains from GBA-PD patients we confirmed reduced CMA activity and proteome changes comparable to those in CMA-deficient mouse brain. Loss of the MT GCase CMA motif is sufficient to rescue primary substantia nigra dopamine neurons from MT-GCase induced neuronal death. We conclude that MT GCase alleles block CMA function and produce -synuclein accumulation.

2022-03-16 | GSE189202 | GEO

Manassantin A inhibits tumour growth under hypoxia through the activation of chaperone-mediated autophagy by modulating Hsp90 activity

Project description:Background: Chaperon-mediated autophagy (CMA) has taken on a new emphasis in cancer biology. However, the roles of CMA in hypoxic tumours are poorly understood. We investigated the anti-tumour effects of the natural product ManA through the activation of CMA in tumour progression under hypoxia. Methods: The effect of ManA on CMA activation was assessed in mouse xenograft models and cells. The gene expressions of HIF-1α, HSP90AA1, and transcription factor EB (TFEB) were analysed using The Cancer Genome Atlas (TCGA) datasets to assess the clinical relevance of CMA. Results: ManA activates photoswitchable CMA reporter activity and inhibits Hsp90 chaperone function by disrupting the Hsp90/F1F0-ATP synthase complex. Hsp90 inhibition enhances the interaction between CMA substrates and LAMP-2A and TFEB nuclear localisation, suggesting CMA activation by ManA. ManA-activated CMA retards tumour growth and displays cooperative anti-tumour activity with anti-PD-1 antibody. TCGA datasets show that a combined expression of HSP90AA1High/HIF1AHigh or TFEBLow/HIF1AHigh is strongly correlated with poor prognosis in patients with lung cancer. Conclusions: ManA-induced CMA activation by modulating Hsp90 under hypoxia induces HIF-1α degradation and reduces tumour growth. Thus, inducing CMA activity by targeting Hsp90 may be a promising therapeutic strategy against hypoxic tumours.

2024-01-22 | GSE110768 | GEO

Exosome-dependent immune surveillance at the metastatic niche requires BAG6

Project description:Extracellular vesicles (EVs) secreted by tumor cells are able to establish a pre-metastatic niche in distant organs, or on the contrary, exert anti-tumor activity. The mechanisms directing distinct EV functions are unknown. Using the B-16V transplantation mouse melanoma model we demonstrate that EVs from B-16V cells mobilize Ly6Clow patrolling monocytes and inhibit lung metastasis. Mechanistically, the formation of anti-tumor-EVs was dependent on the chaperone BAG6 and the acetylation of p53 by the BAG6/CBP/p300-acetylase complex, followed by the recruitment of components of the endosomal sorting complexes required for transport (ESCRT) via a P(S/T)AP double motif of BAG6. By contrast, deficiency of BAG6 led to the release of a distinct vesicle subtype with pro-tumorigenic activity, which recruited neutrophils to the pre-metastatic niche. In humans, BAG6 expression decreases in late-stage melanoma patients, correlating with an increase of the mRNA for the metastasis driver alpha-catulin in EVs, as observed in BAG6-deficient mouse EVs. We conclude that the BAG6/CBP/p300-p53 axis is a key pathway directing EV-formation and function.

2019-11-12 | PXD010677 | Pride

Protective effect of neuronal chaperone-mediated autophagy against brain aging and disease-driven neuroproteotoxicity

Project description:Components of the proteostasis network malfunction in the aging brain and this reduced neuronal protein quality control has been proposed to increase risk for neurodegeneration. Here, we have focused on chaperone-mediated autophagy (CMA), a selective type of autophagy that contributes to turnover of neurodegeneration-related proteins. We generated mouse models with CMA blockage in dopaminergic or glutamatergic neurons to investigate the physiological role of CMA in neurons in vivo and the consequences of neuronal CMA loss in aging, We found that loss of neuronal CMA leads to behavioral impairments, altered neuronal function, selective changes in the neuronal proteome and proteotoxicity, all reminiscent of brain aging. Furthermore, imposing CMA loss on an experimental mouse model of Alzheimer’s disease, increased neuronal disease vulnerability and accelerated disease progression. We conclude that functional CMA is essential for neuronal proteostasis and that CMA activation could be an efficient disease-modifying therapy in neurodegenerative disorders.

2021-04-23 | PXD017108 | Pride

Mechanisms of stop codon readthrough mitigation reveal principles of GCN1 mediated translational quality control

Project description:Readthrough into the 3′ untranslated region (3′UTR) of the mRNA results in the production of aberrant proteins. Metazoans efficiently clear readthrough proteins, but the underlying mechanisms remain unknown. Here, we show in C. elegans and mammalian cells that readthrough proteins are targeted by a coupled, two-level quality control pathway involving the BAG6 chaperone complex and the ribosome collision-sensing protein GCN1. Readthrough proteins with hydrophobic C-terminal extensions are recognized by SGTA-BAG6 and ubiquitylated by RNF126 for proteasomal degradation. Additionally, cotranslational mRNA decay initiated by GCN1 and CCR4/NOT limits the accumulation of readthrough products. Unexpectedly, selective ribosome profiling uncovered a general role of GCN1 in regulating translation dynamics when ribosomes encounter nonoptimal codons, a feature of 3′UTR sequences. Dysfunction of GCN1 results in mRNA and proteome imbalance, increasingly perturbing transmembrane proteins and collagens during aging. These results define GCN1 as a key factor acting during translation in maintaining protein homeostasis.

2023-05-15 | GSE214396 | GEO

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data