The selective autophagy adaptor p62/SQSTM1 forms phase condensates regulated by HSP27 that facilitate the clearance of damaged lysosomes via lysophagy

Gallagher, Elizabeth R; Holzbaur, Erika L.F.

doi:10.1016/j.celrep.2023.112037

Cited by 37 publications

(28 citation statements)

References 108 publications

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“…Unlike OPTN and NDP52, p62 showed enrichment between clustered mitochondria (Mt-Mt), which is consistent with previous reports (Fig. EV1A and B) (Gallagher & Holzbaur, 2023). These accumulation patterns cannot be explained by the stoichiometric interaction of the autophagy adaptors with ubiquitinated proteins that are evenly distributed on mitochondria.…”

Section: Resultssupporting

confidence: 93%

“…When mitophagy was induced by treatment with the mitochondrial uncoupler carbonyl cyanide m -chlorophenylhydrazone (CCCP) in HeLa cells expressing exogenous Parkin, the autophagy adaptors p62, OPTN, NBR1, NDP52, and TAX1BP1 translocated to mitochondria as previously observed (Fig. 1A and B) (Geisler et al , 2010; Wong & Holzbaur, 2014; Heo et al , 2015; Moore & Holzbaur, 2016; Gallagher & Holzbaur, 2023). Ubiquitin and all of these autophagy adaptors were distributed evenly on the surface of separate mitochondria (Mt; Fig.…”

Section: Resultssupporting

confidence: 72%

“…These condensates can be degraded by autophagy, which is termed “fluidophagy” (Agudo-Canalejo et al , 2021). Furthermore, recent studies showed that p62 undergoes LLPS on mitochondria and lysosomes that are subjected to selective autophagy (Peng et al , 2021; Gallagher & Holzbaur, 2023).…”

Section: Introductionmentioning

confidence: 99%

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Autophagy adaptors mediate Parkin-dependent mitophagy by forming sheet-like liquid condensates

Yang,

Yoshii,

Sakai

et al. 2023

Preprint

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During PINK1 and Parkin-mediated mitophagy, autophagy adaptors are recruited to depolarized mitochondria to promote the selective degradation of mitochondria. Autophagy adaptors such as OPTN and NDP52 bridge mitochondria and autophagosomal membranes by binding to ubiquitinated mitochondrial proteins and autophagosomal ATG8 family proteins. Here, we demonstrate that OPTN and NDP52 form sheet-like phase-separated condensates with liquid-like properties on the surface of ubiquitinated mitochondria. The dynamic and liquid-like feature of OPTN condensates is important for mitophagy activity because reducing the liquidity of OPTN-ubiquitin condensates suppresses the recruitment of ATG9 vesicles and impairs mitophagy. Based on these results, we propose a dynamic liquid-like model of autophagy adaptors, in contrast to a stoichiometric model, to explain their interactions between autophagic membranes (i.e., ATG9 vesicles and isolation membranes) and mitochondrial membranes during Parkin-mediated mitophagy. This model underscores the importance of liquid-liquid phase separation in facilitating membrane-membrane contacts, likely through the generation of capillary forces.

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Section: Resultssupporting

confidence: 93%

Section: Resultssupporting

confidence: 72%

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Autophagy adaptors mediate Parkin-dependent mitophagy by forming sheet-like liquid condensates

Yang,

Yoshii,

Sakai

et al. 2023

Preprint

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“…To study astrocyte–neuron (AN) interactions, cortical cell suspensions that contain neurons and astrocytes were obtained from E17‐19 Sprague–Dawley rats (Charles River) prepared by the Neurons R Us service center at the Penn Medicine Translational Neuroscience Center (RRID: SCR_022421) (Calabrese et al, 2022; Gallagher & Holzbaur, 2023). Briefly, five pregnant rats were anesthetized with CO 2 and sacrificed by cervical dislocation.…”

Section: Methodsmentioning

confidence: 99%

Cooperative and competitive regulation of the astrocytic transcriptome by neurons and endothelial cells: Impact on astrocyte maturation

Martínez-Lozada

Farmer

Schober

et al. 2023

Journal of Neurochemistry

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Astrocytes have essential roles in central nervous system (CNS) health and disease. During development, immature astrocytes show complex interactions with neurons, endothelial cells, and other glial cell types. Our work and that of others have shown that these interactions are important for astrocytic maturation. However, whether and how these cells work together to control this process remains poorly understood. Here, we test the hypothesis that cooperative interactions of astrocytes with neurons and endothelial cells promote astrocytic maturation. Astrocytes were cultured alone, with neurons, endothelial cells, or a combination of both. This was followed by astrocyte sorting, RNA sequencing, and bioinformatic analysis to detect transcriptional changes. Across culture configurations, 7302 genes were differentially expressed by 4 or more fold and organized into 8 groups that demonstrate cooperative and antagonist effects of neurons and endothelia on astrocytes. We also discovered that neurons and endothelial cells caused splicing of 200 and 781 mRNAs, respectively. Changes in gene expression were validated using quantitative PCR, western blot (WB), and immunofluorescence analysis. We found that the transcriptomic data from the three‐culture configurations correlated with protein expression of three representative targets (FAM107A, GAT3, and GLT1) in vivo. Alternative splicing results also correlated with cortical tissue isoform representation of a target (Fibronectin 1) at different developmental stages. By comparing our results to published transcriptomes of immature and mature astrocytes, we found that neurons or endothelia shift the astrocytic transcriptome toward a mature state and that the presence of both cell types has a greater effect on maturation than either cell alone. These results increase our understanding of cellular interactions/pathways that contribute to astrocytic maturation. They also provide insight into how alterations to neurons and/or endothelial cells may alter astrocytes with implications for astrocytic changes in CNS disorders and diseases.image

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“…36 SQSTM1 can form condensates with ubiquitinated cargos, linked to the formation of autophagosomes. 27,37,38 p-SQSTM1 (Ser403) (green) and SQSTM1 (red) colocalized to form condensates after Nab-PTX treatment (Figure 1C, yellow). LC3-II (green) and LAMP1 (red) were also colocalized after Nab-PTX treatment (Figure 1D, yellow).…”

Section: Nab-ptx Increases Protein Levels Of P-sqstm1 (Ser403) and Lc...mentioning

confidence: 99%

Enhancing Efficacy of Albumin-Bound Paclitaxel for Human Lung and Colorectal Cancers through Autophagy Receptor Sequestosome 1 (SQSTM1)/p62-Mediated Nanodrug Delivery and Cancer therapy

Lin,

Chen

et al. 2023

ACS Nano

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Selective autophagy is a defense mechanism by which foreign pathogens and abnormal substances are processed to maintain cellular homeostasis. Sequestosome 1 (SQSTM1)/p62, a vital selective autophagy receptor, recruits ubiquitinated cargo to form autophagosomes for lysosomal degradation. Nab-PTX is an albumin-bound paclitaxel nanoparticle used in clinical cancer therapy. However, the role of SQSTM1 in regulating the delivery and efficacy of nanodrugs remains unclear. Here we showed that SQSTM1 plays a crucial role in Nab-PTX drug delivery and efficacy in human lung and colorectal cancers. Nab-PTX induces SQSTM1 phosphorylation at Ser403, which facilitates its incorporation into the selective autophagy of nanoparticles, known as nanoparticulophagy. Nab-PTX increased LC3-II protein expression, which triggered autophagosome formation. SQSTM1 enhanced Nab-PTX recognition to form autophagosomes, which were delivered to lysosomes for albumin degradation, thereby releasing PTX to induce mitotic catastrophe and apoptosis. Knockout of SQSTM1 downregulated Nab-PTX-induced mitotic catastrophe, apoptosis, and tumor inhibition in vitro and in vivo and inhibited Nab-PTX-induced caspase 3 activation via a p53-independent pathway. Ectopic expression of SQSTM1 by transfection of an SQSTM1-GFP vector restored the drug efficacy of Nab-PTX. Importantly, SQSTM1 is highly expressed in advanced lung and colorectal tumors and is associated with poor overall survival in clinical patients. Targeting SQSTM1 may provide an important strategy to improve nanodrug efficacy in clinical cancer therapy. This study demonstrates the enhanced efficacy of Nab-PTX for human lung and colorectal cancers via SQSTM1-mediated nanodrug delivery.

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The selective autophagy adaptor p62/SQSTM1 forms phase condensates regulated by HSP27 that facilitate the clearance of damaged lysosomes via lysophagy

Cited by 37 publications

References 108 publications

Autophagy adaptors mediate Parkin-dependent mitophagy by forming sheet-like liquid condensates

Autophagy adaptors mediate Parkin-dependent mitophagy by forming sheet-like liquid condensates

Cooperative and competitive regulation of the astrocytic transcriptome by neurons and endothelial cells: Impact on astrocyte maturation

Enhancing Efficacy of Albumin-Bound Paclitaxel for Human Lung and Colorectal Cancers through Autophagy Receptor Sequestosome 1 (SQSTM1)/p62-Mediated Nanodrug Delivery and Cancer therapy

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