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1.
Mol Cell ; 84(10): 1980-1994.e8, 2024 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-38759629

RESUMO

Aggregation of proteins containing expanded polyglutamine (polyQ) repeats is the cytopathologic hallmark of a group of dominantly inherited neurodegenerative diseases, including Huntington's disease (HD). Huntingtin (Htt), the disease protein of HD, forms amyloid-like fibrils by liquid-to-solid phase transition. Macroautophagy has been proposed to clear polyQ aggregates, but the efficiency of aggrephagy is limited. Here, we used cryo-electron tomography to visualize the interactions of autophagosomes with polyQ aggregates in cultured cells in situ. We found that an amorphous aggregate phase exists next to the radially organized polyQ fibrils. Autophagosomes preferentially engulfed this amorphous material, mediated by interactions between the autophagy receptor p62/SQSTM1 and the non-fibrillar aggregate surface. In contrast, amyloid fibrils excluded p62 and evaded clearance, resulting in trapping of autophagic structures. These results suggest that the limited efficiency of autophagy in clearing polyQ aggregates is due to the inability of autophagosomes to interact productively with the non-deformable, fibrillar disease aggregates.


Assuntos
Amiloide , Autofagossomos , Autofagia , Proteína Huntingtina , Doença de Huntington , Peptídeos , Agregados Proteicos , Proteína Sequestossoma-1 , Peptídeos/metabolismo , Peptídeos/química , Peptídeos/genética , Humanos , Proteína Huntingtina/metabolismo , Proteína Huntingtina/genética , Proteína Huntingtina/química , Autofagossomos/metabolismo , Autofagossomos/ultraestrutura , Proteína Sequestossoma-1/metabolismo , Proteína Sequestossoma-1/genética , Amiloide/metabolismo , Amiloide/química , Amiloide/genética , Doença de Huntington/metabolismo , Doença de Huntington/genética , Doença de Huntington/patologia , Microscopia Crioeletrônica , Animais , Agregação Patológica de Proteínas/metabolismo , Agregação Patológica de Proteínas/genética
2.
Mol Cell ; 82(5): 886-888, 2022 03 03.
Artigo em Inglês | MEDLINE | ID: mdl-35245454

RESUMO

Zervopoulos et al. (2022) propose a non-canonical nuclear import pathway for the functional mitochondrial pyruvate dehydrogenase complex (PDC), facilitated by dynamic MFN2-mediated tethering of mitochondria to the nuclear envelope upon exposure to proliferative stimuli.


Assuntos
Mitocôndrias , Complexo Piruvato Desidrogenase , Núcleo Celular/metabolismo , Mitocôndrias/genética , Mitocôndrias/metabolismo , Complexo Piruvato Desidrogenase/genética , Complexo Piruvato Desidrogenase/metabolismo
3.
Mol Cell ; 80(5): 764-778.e7, 2020 12 03.
Artigo em Inglês | MEDLINE | ID: mdl-33207182

RESUMO

Autophagy eliminates cytoplasmic content selected by autophagy receptors, which link cargo to the membrane-bound autophagosomal ubiquitin-like protein Atg8/LC3. Here, we report a selective autophagy pathway for protein condensates formed by endocytic proteins in yeast. In this pathway, the endocytic protein Ede1 functions as a selective autophagy receptor. Distinct domains within Ede1 bind Atg8 and mediate phase separation into condensates. Both properties are necessary for an Ede1-dependent autophagy pathway for endocytic proteins, which differs from regular endocytosis and does not involve other known selective autophagy receptors but requires the core autophagy machinery. Cryo-electron tomography of Ede1-containing condensates, at the plasma membrane and in autophagic bodies, shows a phase-separated compartment at the beginning and end of the Ede1-mediated selective autophagy route. Our data suggest a model for autophagic degradation of macromolecular protein complexes by the action of intrinsic autophagy receptors.


Assuntos
Família da Proteína 8 Relacionada à Autofagia , Autofagia , Endocitose , Modelos Biológicos , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae , Família da Proteína 8 Relacionada à Autofagia/química , Família da Proteína 8 Relacionada à Autofagia/metabolismo , Microscopia Crioeletrônica , Ligação Proteica , Proteólise , Saccharomyces cerevisiae/química , Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/ultraestrutura , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/metabolismo
4.
Nature ; 586(7831): 796-800, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32879490

RESUMO

Nuclear pore complexes (NPCs) fuse the inner and outer membranes of the nuclear envelope. They comprise hundreds of nucleoporins (Nups) that assemble into multiple subcomplexes and form large central channels for nucleocytoplasmic exchange1,2. How this architecture facilitates messenger RNA export, NPC biogenesis and turnover remains poorly understood. Here we combine in situ structural biology and integrative modelling with correlative light and electron microscopy and molecular perturbation to structurally analyse NPCs in intact Saccharomyces cerevisiae cells within the context of nuclear envelope remodelling. We find an in situ conformation and configuration of the Nup subcomplexes that was unexpected from the results of previous in vitro analyses. The configuration of the Nup159 complex appears critical to spatially accommodate its function as an mRNA export platform, and as a mediator of NPC turnover. The omega-shaped nuclear envelope herniae that accumulate in nup116Δ cells3 conceal partially assembled NPCs lacking multiple subcomplexes, including the Nup159 complex. Under conditions of starvation, herniae of a second type are formed that cytoplasmically expose NPCs. These results point to a model of NPC turnover in which NPC-containing vesicles bud off from the nuclear envelope before degradation by the autophagy machinery. Our study emphasizes the importance of investigating the structure-function relationship of macromolecular complexes in their cellular context.


Assuntos
Microscopia Crioeletrônica , Poro Nuclear/metabolismo , Poro Nuclear/ultraestrutura , Saccharomyces cerevisiae/citologia , Saccharomyces cerevisiae/ultraestrutura , Autofagia , Modelos Moleculares , Poro Nuclear/química , Complexo de Proteínas Formadoras de Poros Nucleares/metabolismo , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Tomografia
5.
Proc Natl Acad Sci U S A ; 120(12): e2221712120, 2023 03 21.
Artigo em Inglês | MEDLINE | ID: mdl-36917659

RESUMO

Selective macroautophagy (hereafter referred to as autophagy) describes a process in which cytosolic material is engulfed in a double membrane organelle called an autophagosome. Autophagosomes are carriers responsible for delivering their content to a lytic compartment for destruction. The cargo can be of diverse origin, ranging from macromolecular complexes to protein aggregates, organelles, and even invading pathogens. Each cargo is unique in composition and size, presenting different challenges to autophagosome biogenesis. Among the largest cargoes targeted by the autophagy machinery are intracellular bacteria, which can, in the case of Salmonella, range from 2 to 5 µm in length and 0.5 to 1.5 µm in width. How phagophores form and expand on such a large cargo remains mechanistically unclear. Here, we used HeLa cells infected with an auxotrophic Salmonella to study the process of phagophore biogenesis using in situ correlative cryo-ET. We show that host cells generate multiple phagophores at the site of damaged Salmonella-containing vacuoles (SCVs). The observed double membrane structures range from disk-shaped to expanded cup-shaped phagophores, which have a thin intermembrane lumen with a dilating rim region and expand using the SCV, the outer membrane of Salmonella, or existing phagophores as templates. Phagophore rims establish different forms of contact with the endoplasmic reticulum (ER) via structurally distinct molecular entities for membrane formation and expansion. Early omegasomes correlated with the marker Double-FYVE domain-Containing Protein 1 (DFCP1) are observed in close association with the ER without apparent membrane continuity. Our study provides insights into the formation of phagophores around one of the largest selective cargoes.


Assuntos
Autofagossomos , Macroautofagia , Humanos , Autofagossomos/metabolismo , Autofagia , Retículo Endoplasmático/metabolismo , Células HeLa
6.
J Biol Chem ; 300(10): 107766, 2024 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-39276934

RESUMO

Liquid protein condensates produced by phase separation are involved in the spatiotemporal control of cellular functions, while solid fibrous aggregates (amyloids) are associated with diseases and/or manifest as infectious or heritable elements (prions). Relationships between these assemblies are poorly understood. The Saccharomyces cerevisiae release factor Sup35 can produce both fluid liquid-like condensates (e.g., at acidic pH) and amyloids (typically cross-seeded by other prions). We observed acidification-independent formation of Sup35-based liquid condensates in response to hyperosmotic shock in the absence of other prions, both at increased and physiological expression levels. The Sup35 prion domain, Sup35N, is both necessary and sufficient for condensate formation, while the middle domain, Sup35M antagonizes this process. Formation of liquid condensates in response to osmotic stress is conserved within yeast evolution. Notably, condensates of Sup35N/NM protein originated from the distantly related yeast Ogataea methanolica can directly convert to amyloids in osmotically stressed S. cerevisiae cells, providing a unique opportunity for real-time monitoring of condensate-to-fibril transition in vivo by fluorescence microscopy. Thus, cellular fate of stress-induced condensates depends on protein properties and/or intracellular environment.

7.
Proc Natl Acad Sci U S A ; 119(39): e2209823119, 2022 09 27.
Artigo em Inglês | MEDLINE | ID: mdl-36122245

RESUMO

Autophagosomes are unique organelles that form de novo as double-membrane vesicles engulfing cytosolic material for destruction. Their biogenesis involves membrane transformations of distinctly shaped intermediates whose ultrastructure is poorly understood. Here, we combine cell biology, correlative cryo-electron tomography (cryo-ET), and extensive data analysis to reveal the step-by-step structural progression of autophagosome biogenesis at high resolution directly within yeast cells. The analysis uncovers an unexpectedly thin intermembrane distance that is dilated at the phagophore rim. Mapping of individual autophagic structures onto a timeline based on geometric features reveals a dynamical change of membrane shape and curvature in growing phagophores. Moreover, our tomograms show the organelle interactome of growing autophagosomes, highlighting a polar organization of contact sites between the phagophore and organelles, such as the vacuole and the endoplasmic reticulum (ER). Collectively, these findings have important implications for the contribution of different membrane sources during autophagy and for the forces shaping and driving phagophores toward closure without a templating cargo.


Assuntos
Autofagossomos , Macroautofagia , Vacúolos , Autofagossomos/metabolismo , Membrana Celular , Retículo Endoplasmático/metabolismo , Saccharomyces cerevisiae , Vacúolos/metabolismo
8.
EMBO Rep ; 23(12): e53065, 2022 12 06.
Artigo em Inglês | MEDLINE | ID: mdl-36215690

RESUMO

Autophagy is responsible for clearance of an extensive portfolio of cargoes, which are sequestered into vesicles, called autophagosomes, and are delivered to lysosomes for degradation. The pathway is highly dynamic and responsive to several stress conditions. However, the phospholipid composition and protein contents of human autophagosomes under changing autophagy rates are elusive so far. Here, we introduce an antibody-based FACS-mediated approach for the isolation of native autophagic vesicles and ensured the quality of the preparations. Employing quantitative lipidomics, we analyze phospholipids present within human autophagic vesicles purified upon basal autophagy, starvation, and proteasome inhibition. Importantly, besides phosphoglycerides, we identify sphingomyelin within autophagic vesicles and show that the phospholipid composition is unaffected by the different conditions. Employing quantitative proteomics, we obtain cargo profiles of autophagic vesicles isolated upon the different treatment paradigms. Interestingly, starvation shows only subtle effects, while proteasome inhibition results in the enhanced presence of ubiquitin-proteasome pathway factors within autophagic vesicles. Thus, here we present a powerful method for the isolation of native autophagic vesicles, which enabled profound phospholipid and cargo analyses.


Assuntos
Complexo de Endopeptidases do Proteassoma , Proteômica , Humanos , Autofagia , Fosfolipídeos
9.
J Biol Chem ; 298(7): 102083, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35636514

RESUMO

The ubiquitin-proteasome system fulfills an essential role in regulating protein homeostasis by spatially and temporally controlling proteolysis in an ATP- and ubiquitin-dependent manner. However, the localization of proteasomes is highly variable under diverse cellular conditions. In yeast, newly synthesized proteasomes are primarily localized to the nucleus during cell proliferation. Yeast proteasomes are transported into the nucleus through the nuclear pore either as immature subcomplexes or as mature enzymes via adapter proteins Sts1 and Blm10, while in mammalian cells, postmitotic uptake of proteasomes into the nucleus is mediated by AKIRIN2, an adapter protein essentially required for nuclear protein degradation. Stressful growth conditions and the reversible halt of proliferation, that is quiescence, are associated with a decline in ATP and the reorganization of proteasome localization. Cellular stress leads to proteasome accumulation in membraneless granules either in the nucleus or in the cytoplasm. In quiescence, yeast proteasomes are sequestered in an ubiquitin-dependent manner into motile and reversible proteasome storage granules in the cytoplasm. In cancer cells, upon amino acid deprivation, heat shock, osmotic stress, oxidative stress, or the inhibition of either proteasome activity or nuclear export, reversible proteasome foci containing polyubiquitinated substrates are formed by liquid-liquid phase separation in the nucleus. In this review, we summarize recent literature revealing new links between nuclear transport, ubiquitin signaling, and the intracellular organization of proteasomes during cellular stress conditions.


Assuntos
Complexo de Endopeptidases do Proteassoma , Saccharomyces cerevisiae , Transporte Ativo do Núcleo Celular , Trifosfato de Adenosina/metabolismo , Animais , Citoplasma/metabolismo , Mamíferos/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo , Saccharomyces cerevisiae/metabolismo , Ubiquitina/metabolismo
12.
Proc Natl Acad Sci U S A ; 110(33): 13244-9, 2013 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-23901109

RESUMO

Intracellular trafficking between organelles is achieved by coat protein complexes, coat protomers, that bud vesicles from bilayer membranes. Lipid droplets are protected by a monolayer and thus seem unsuitable targets for coatomers. Unexpectedly, coat protein complex I (COPI) is required for lipid droplet targeting of some proteins, suggesting a possible direct interaction between COPI and lipid droplets. Here, we find that COPI coat components can bud 60-nm triacylglycerol nanodroplets from artificial lipid droplet (LD) interfaces. This budding decreases phospholipid packing of the monolayer decorating the mother LD. As a result, hydrophobic triacylglycerol molecules become more exposed to the aqueous environment, increasing LD surface tension. In vivo, this surface tension increase may prime lipid droplets for reactions with neighboring proteins or membranes. It provides a mechanism fundamentally different from transport vesicle formation by COPI, likely responsible for the diverse lipid droplet phenotypes associated with depletion of COPI subunits.


Assuntos
Complexo I de Proteína do Envoltório/química , Bicamadas Lipídicas/química , Transporte Proteico/fisiologia , Vesículas Transportadoras/química , Fator 1 de Ribosilação do ADP/genética , Animais , Escherichia coli , Humanos , Interações Hidrofóbicas e Hidrofílicas , Microscopia Eletrônica , Fosfatidilcolinas , Fosfatidiletanolaminas , Fosfolipídeos/química , Células Sf9 , Espectrometria de Fluorescência , Spodoptera , Tensão Superficial , Triglicerídeos/química , Água/química
13.
Mol Cell Proteomics ; 12(5): 1115-26, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23319140

RESUMO

Lipid droplets (LDs) are important organelles in energy metabolism and lipid storage. Their cores are composed of neutral lipids that form a hydrophobic phase and are surrounded by a phospholipid monolayer that harbors specific proteins. Most well-established LD proteins perform important functions, particularly in cellular lipid metabolism. Morphological studies show LDs in close proximity to and interacting with membrane-bound cellular organelles, including the endoplasmic reticulum, mitochondria, peroxisomes, and endosomes. Because of these close associations, it is difficult to purify LDs to homogeneity. Consequently, the confident identification of bona fide LD proteins via proteomics has been challenging. Here, we report a methodology for LD protein identification based on mass spectrometry and protein correlation profiles. Using LD purification and quantitative, high-resolution mass spectrometry, we identified LD proteins by correlating their purification profiles to those of known LD proteins. Application of the protein correlation profile strategy to LDs isolated from Drosophila S2 cells led to the identification of 111 LD proteins in a cellular LD fraction in which 1481 proteins were detected. LD localization was confirmed in a subset of identified proteins via microscopy of the expressed proteins, thereby validating the approach. Among the identified LD proteins were both well-characterized LD proteins and proteins not previously known to be localized to LDs. Our method provides a high-confidence LD proteome of Drosophila cells and a novel approach that can be applied to identify LD proteins of other cell types and tissues.


Assuntos
Proteínas de Drosophila/metabolismo , Organelas/metabolismo , Proteoma/metabolismo , Animais , Biomarcadores/metabolismo , Linhagem Celular , Drosophila melanogaster , Metabolismo dos Lipídeos , Fenótipo , Espectrometria de Massas em Tandem
14.
J Mol Biol ; 436(15): 168574, 2024 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-38636617

RESUMO

Proteins are known to perform an astonishing array of functions thanks to their ability to cooperate and modulate each other's properties. Inside cells, proteins can assemble into large multi-subunit complexes to carry out complex cellular functions. The correct assembly and maintenance of the functional state of macromolecular protein complexes is crucial for human health. Failure to do so leads to loss of function and potential accumulation of harmful materials, which is associated with a variety of human diseases such as neurodegeneration and cancer. Autophagy engulfs cytosolic material in autophagosomes, and therefore is best suited to eliminate intact macromolecular complexes without disassembling them, which could interfere with de novo assembly. In this review, we discuss the role of autophagy in the selective degradation of macromolecular complexes. We highlight the current state of knowledge for different macromolecular complexes and their selective autophagic degradation. We emphasize the gaps in our understanding of what it takes for these large macromolecular complexes to be degraded and point to future work that may shed light on the regulation of the selective degradation of macromolecular complexes by autophagy.


Assuntos
Autofagia , Substâncias Macromoleculares , Humanos , Substâncias Macromoleculares/metabolismo , Animais , Autofagossomos/metabolismo , Proteólise , Complexos Multiproteicos/metabolismo
15.
Nat Cell Biol ; 26(3): 378-392, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38429475

RESUMO

The endoplasmic reticulum (ER) employs a diverse proteome landscape to orchestrate many cellular functions, ranging from protein and lipid synthesis to calcium ion flux and inter-organelle communication. A case in point concerns the process of neurogenesis, where a refined tubular ER network is assembled via ER shaping proteins into the newly formed neuronal projections to create highly polarized dendrites and axons. Previous studies have suggested a role for autophagy in ER remodelling, as autophagy-deficient neurons in vivo display axonal ER accumulation within synaptic boutons, and the membrane-embedded ER-phagy receptor FAM134B has been genetically linked with human sensory and autonomic neuropathy. However, our understanding of the mechanisms underlying selective removal of the ER and the role of individual ER-phagy receptors is limited. Here we combine a genetically tractable induced neuron (iNeuron) system for monitoring ER remodelling during in vitro differentiation with proteomic and computational tools to create a quantitative landscape of ER proteome remodelling via selective autophagy. Through analysis of single and combinatorial ER-phagy receptor mutants, we delineate the extent to which each receptor contributes to both the magnitude and selectivity of ER protein clearance. We define specific subsets of ER membrane or lumenal proteins as preferred clients for distinct receptors. Using spatial sensors and flux reporters, we demonstrate receptor-specific autophagic capture of ER in axons, and directly visualize tubular ER membranes within autophagosomes in neuronal projections by cryo-electron tomography. This molecular inventory of ER proteome remodelling and versatile genetic toolkit provide a quantitative framework for understanding the contributions of individual ER-phagy receptors for reshaping ER during cell state transitions.


Assuntos
Proteoma , Proteômica , Humanos , Retículo Endoplasmático/metabolismo , Autofagia/fisiologia , Estresse do Retículo Endoplasmático , Proteínas de Transporte/metabolismo , Neurogênese
16.
bioRxiv ; 2024 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-38585873

RESUMO

Lysosomal storage diseases (LSDs) comprise ~50 monogenic disorders marked by the buildup of cellular material in lysosomes, yet systematic global molecular phenotyping of proteins and lipids is lacking. We present a nanoflow-based multi-omic single-shot technology (nMOST) workflow that quantifies HeLa cell proteomes and lipidomes from over two dozen LSD mutants. Global cross-correlation analysis between lipids and proteins identified autophagy defects, notably the accumulation of ferritinophagy substrates and receptors, especially in NPC1 -/- and NPC2 -/- mutants, where lysosomes accumulate cholesterol. Autophagic and endocytic cargo delivery failures correlated with elevated lyso-phosphatidylcholine species and multi-lamellar structures visualized by cryo-electron tomography. Loss of mitochondrial cristae, MICOS-complex components, and OXPHOS components rich in iron-sulfur cluster proteins in NPC2 -/- cells was largely alleviated when iron was provided through the transferrin system. This study reveals how lysosomal dysfunction affects mitochondrial homeostasis and underscores nMOST as a valuable discovery tool for identifying molecular phenotypes across LSDs.

17.
FEBS Lett ; 597(22): 2728-2738, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37567863

RESUMO

Due to their essential functions, dysregulation of nuclear pore complexes (NPCs) is strongly associated with numerous human diseases, including neurodegeneration and cancer. On a cellular level, longevity of scaffold nucleoporins in postmitotic cells of both C. elegans and mammals renders them vulnerable to age-related damage, which is associated with an increase in pore leakiness and accumulation of intranuclear aggregates in rat brain cells. Thus, understanding the mechanisms which underpin the homeostasis of this complex, as well as other nuclear proteins, is essential. In this review, autophagy-mediated degradation pathways governing nuclear components in yeast will be discussed, with a particular focus on NPCs. Furthermore, the various nuclear degradation mechanisms identified thus far in diverse eukaryotes will also be highlighted.


Assuntos
Caenorhabditis elegans , Poro Nuclear , Ratos , Humanos , Animais , Caenorhabditis elegans/metabolismo , Poro Nuclear/metabolismo , Complexo de Proteínas Formadoras de Poros Nucleares/metabolismo , Núcleo Celular/metabolismo , Saccharomyces cerevisiae/metabolismo , Autofagia , Mamíferos/metabolismo
18.
Curr Opin Cell Biol ; 85: 102258, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37832166

RESUMO

With an essential role in nearly every physiological process and disease state, trafficking vesicles are fundamental to cell biology. Canonical understanding of membrane traffic has been driven by key achievements in structural biology. Nonetheless, discoveries over the past few years progressively point to the critical role of intrinsically disordered domains and proteins, which lack a well-defined secondary structure. From the initiation of endocytosis and the sequestration of synaptic vesicles to the stabilization of endoplasmic reticulum exit sites and the extension of the autophagic cup, flexible protein condensates, rich in intrinsic disorder, are increasingly implicated. While important debates about the physical nature and mechanistic interpretation of these findings remain, the significance of transient, multivalent protein assemblies in membrane traffic is increasingly clear.


Assuntos
Retículo Endoplasmático , Proteínas , Proteínas/metabolismo , Retículo Endoplasmático/metabolismo , Transporte Proteico
19.
Contact (Thousand Oaks) ; 6: 25152564231162495, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37366413

RESUMO

During macroautophagy, phagophores establish multiple membrane contact sites (MCSs) with other organelles that are pivotal for proper phagophore assembly and growth. In S. cerevisiae, phagophore contacts have been observed with the vacuole, the ER, and lipid droplets. In situ imaging studies have greatly advanced our understanding of the structure and function of these sites. Here, we discuss how in situ structural methods like cryo-CLEM can give unprecedented insights into MCSs, and how they help to elucidate the structural arrangements of MCSs within cells. We further summarize the current knowledge of the contact sites in autophagy, focusing on autophagosome biogenesis in the model organism S. cerevisiae.

20.
Autophagy ; 19(7): 2146-2147, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-36416088

RESUMO

Autophagosome isolation enables the thorough investigation of structural components and engulfed materials. Recently, we introduced a novel antibody-based FACS-mediated method for isolation of native macroautophagic/autophagic vesicles and confirmed the quality of the preparations. We performed phospholipidomic and proteomic analyses to characterize autophagic vesicle-associated phospholipids and protein cargoes under different autophagy conditions. Lipidomic analyses identified phosphoglycerides and sphingomyelins within autophagic vesicles and revealed that the lipid composition was unaffected by different rates of autophagosome formation. Proteomic analyses identified more than 4500 potential autophagy substrates and showed that in comparison to autophagic vesicles isolated under basal autophagy conditions, starvation only marginally affected the cargo profile. Proteasome inhibition, however, resulted in the enhanced degradation of ubiquitin-proteasome system components. Taken together, the novel isolation method enriched large quantities of autophagic vesicles and enabled detailed analyses of their lipid and cargo composition.


Assuntos
Autofagia , Complexo de Endopeptidases do Proteassoma , Autofagia/fisiologia , Complexo de Endopeptidases do Proteassoma/metabolismo , Proteômica , Autofagossomos/metabolismo , Lipídeos
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