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Jun Hee Lee - One of the best experts on this subject based on the ideXlab platform.
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sestrin2 promotes unc 51 like kinase 1 mediated phosphorylation of P62 sequestosome 1
FEBS Journal, 2014Co-Authors: Ian A Semple, Hwanwoo Park, Haeli Park, Hae-won Park, Myungjin Kim, Jeong Sig Kim, Jun Hee LeeAbstract:Autophagy is a homeostatic process that is important for degrading protein aggregates, nutrient deposits, dysfunctional organelles and several signaling molecules. P62/sequestosome-1 is a protein that binds to several autophagy substrates, such as ubiquitinated proteins, damaged mitochondria and signaling molecules such as an Nrf2 inhibitor Keap1, promoting their autophagic degradation. Sestrin2, a stress-inducible protein, has been recently shown to bind to P62 and promote autophagic degradation of such P62 targets. Because Sestrin2 is a metabolic regulator that suppresses diverse age- and obesity-associated pathologies, the autophagy-controlling function of Sestrin2 may be important for its other physiological functions. However, the molecular mechanism of how Sestrin2 can promote clearance of P62-associated proteins has been unclear. Here we show that Sestrin2 physically associates with ULK1 and P62 to form a complex, in which both Sestrin2 and P62 become phosphorylated by ULK1 at multiple sites. Ser403 of P62, whose phosphorylation is known to promote autophagic degradation of P62 and its targets, is among the sites phosphorylated by ULK1. ULK1-mediated P62 phosphorylation was facilitated by Sestrin2 in cells as well as in vitro kinase assays. Consistent with this finding, oligomycin-induced energy deprivation, which strongly activates ULK1, provoked a robust Ser403 phosphorylation of P62 in wild-type (WT) mouse embryonic fibroblasts (MEF). However, in ULK1/2- and Sestrin2-deficient MEF, oligomycin-induced P62 phosphorylation was dramatically attenuated, suggesting that endogenous Sestrin2-ULK1/2 mainly mediates P62 phosphorylation in response to energetic stress. Taken together, this study identifies ULK1 as a new P62 Ser403 kinase and establishes Sestrin2 as a promoter of ULK1-mediated P62 phosphorylation.
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Sestrin2 promotes Unc-51-like kinase 1 mediated phosphorylation of P62/sequestosome-1
FEBS Journal, 2014Co-Authors: Ian A Semple, Hwanwoo Park, Haeli Park, Hae-won Park, Myungjin Kim, Jeong Sig Kim, Jun Hee LeeAbstract:Autophagy is a homeostatic process that is important for degrading protein aggregates, nutrient deposits, dysfunctional organelles and several signaling molecules. P62/sequestosome-1 is a protein that binds to several autophagy substrates, such as ubiquitinated proteins, damaged mitochondria and signaling molecules such as an Nrf2 inhibitor Keap1, promoting their autophagic degradation. Sestrin2, a stress-inducible protein, has been recently shown to bind to P62 and promote autophagic degradation of such P62 targets. Because Sestrin2 is a metabolic regulator that suppresses diverse age- and obesity-associated pathologies, the autophagy-controlling function of Sestrin2 may be important for its other physiological functions. However, the molecular mechanism of how Sestrin2 can promote clearance of P62-associated proteins has been unclear. Here we show that Sestrin2 physically associates with ULK1 and P62 to form a complex, in which both Sestrin2 and P62 become phosphorylated by ULK1 at multiple sites. Ser403 of P62, whose phosphorylation is known to promote autophagic degradation of P62 and its targets, is among the sites phosphorylated by ULK1. ULK1-mediated P62 phosphorylation was facilitated by Sestrin2 in cells as well as in vitro kinase assays. Consistent with this finding, oligomycin-induced energy deprivation, which strongly activates ULK1, provoked a robust Ser403 phosphorylation of P62 in wild-type (WT) mouse embryonic fibroblasts (MEF). However, in ULK1/2- and Sestrin2-deficient MEF, oligomycin-induced P62 phosphorylation was dramatically attenuated, suggesting that endogenous Sestrin2-ULK1/2 mainly mediates P62 phosphorylation in response to energetic stress. Taken together, this study identifies ULK1 as a new P62 Ser403 kinase and establishes Sestrin2 as a promoter of ULK1-mediated P62 phosphorylation.
Kai Kaarniranta - One of the best experts on this subject based on the ideXlab platform.
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the P62 sequestosome 1 binds irreversibly to protein aggregates prior to autophagy clearance in arpe 19 cells
Acta Ophthalmologica, 2012Co-Authors: Johanna Viiri, Jari Hyttinen, Antero Salminen, Kai KaarnirantaAbstract:Purpose The pathogenesis of AMD involves impaired protein degradation in RPE cells. The ubiquitin-proteasome pathway and the lysosomal pathway including autophagy are the major proteolytic systems in eukaryotic cells. Recently, P62/sequestosome 1 (P62) has been shown to be a key player linking the proteasomal and lysosomal clearance systems. In this study, expression and trafficking of P62 was examined. Methods To study the effect of autophagy activator (AICAR) and inhibitor (bafilomycin) on P62 expression levels, the ARPE-19 cells were treated with proteasome inhibitor (MG-132, 5µM) with or without AICAR (2mM) or bafilomycin (50nM) for 24h hours. The protein levels of P62 were evaluated by western blotting. The localization and movement of P62 were analyzed by live confocal microscopy. Results MG-132 increased the P62 protein levels, while AICAR robustly decreased the P62 levels. When autophagy was inhibited with bafilomycin the P62 was highly accumulated. We show that P62 binds irreversibly to protein aggregates that are finally degraded in autophagy. Conclusion The P62/sequestosome 1 function as a linker protein between proteasomes and autophagy and can be used as a autophagy flux marker. Autophagy is effective clearance machine that may be disturbed in aged RPE cells.
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The P62/sequestosome 1 binds irreversibly to protein aggregates prior to autophagy clearance in ARPE-19 cells
Acta Ophthalmologica, 2012Co-Authors: Johanna Viiri, Jari Hyttinen, Antero Salminen, Kai KaarnirantaAbstract:Purpose The pathogenesis of AMD involves impaired protein degradation in RPE cells. The ubiquitin-proteasome pathway and the lysosomal pathway including autophagy are the major proteolytic systems in eukaryotic cells. Recently, P62/sequestosome 1 (P62) has been shown to be a key player linking the proteasomal and lysosomal clearance systems. In this study, expression and trafficking of P62 was examined. Methods To study the effect of autophagy activator (AICAR) and inhibitor (bafilomycin) on P62 expression levels, the ARPE-19 cells were treated with proteasome inhibitor (MG-132, 5µM) with or without AICAR (2mM) or bafilomycin (50nM) for 24h hours. The protein levels of P62 were evaluated by western blotting. The localization and movement of P62 were analyzed by live confocal microscopy. Results MG-132 increased the P62 protein levels, while AICAR robustly decreased the P62 levels. When autophagy was inhibited with bafilomycin the P62 was highly accumulated. We show that P62 binds irreversibly to protein aggregates that are finally degraded in autophagy. Conclusion The P62/sequestosome 1 function as a linker protein between proteasomes and autophagy and can be used as a autophagy flux marker. Autophagy is effective clearance machine that may be disturbed in aged RPE cells.
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Emerging role of P62/sequestosome-1 in the pathogenesis of Alzheimer's disease.
Progress in Neurobiology, 2012Co-Authors: Antero Salminen, Kai Kaarniranta, Annakaisa Haapasalo, Mikko Hiltunen, Hilkka Soininen, Irina AlafuzoffAbstract:The P62/sequestosome-1 is a multifunctional protein containing several protein-protein interaction domains. Through these interactions P62 is involved in the regulation of cellular signaling and protein trafficking, aggregation and degradation. P62 protein can bind through its UBA motif to ubiquitinated proteins and control their aggregation and degradation via either autophagy or proteasomes. P62 protein has been reported to be seen in association with the intracellular inclusions in primary and secondary tauopathies, α-synucleinopathies and other neurodegenerative brain disorders displaying inclusions with misfolded proteins. In Alzheimer's disease (AD), P62 protein is associated with neurofibrillary tangles composed primarily of hyperphosphorylated tau protein and ubiquitin. Increasing evidence indicates that P62 has an important role in the degradation of tau protein. The lack of P62 protein expression provokes the tau pathology in mice. Recent studies have demonstrated that the P62 gene expression and cytoplasmic P62 protein levels are significantly reduced in the frontal cortex of AD patients. Decline in the level of P62 protein can disturb the signaling pathways of Nrf2, cyclic AMP and NF-κB and in that way increase oxidative stress and impair neuronal survival. We will review here the molecular and functional characteristics of P62 protein and outline its potential role in the regulation of Alzheimer's pathogenesis.
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emerging role of P62 sequestosome 1 in the pathogenesis of alzheimer s disease
Progress in Neurobiology, 2012Co-Authors: Antero Salminen, Kai Kaarniranta, Annakaisa Haapasalo, Mikko Hiltunen, Hilkka Soininen, Irina AlafuzoffAbstract:The P62/sequestosome-1 is a multifunctional protein containing several protein-protein interaction domains. Through these interactions P62 is involved in the regulation of cellular signaling and protein trafficking, aggregation and degradation. P62 protein can bind through its UBA motif to ubiquitinated proteins and control their aggregation and degradation via either autophagy or proteasomes. P62 protein has been reported to be seen in association with the intracellular inclusions in primary and secondary tauopathies, α-synucleinopathies and other neurodegenerative brain disorders displaying inclusions with misfolded proteins. In Alzheimer's disease (AD), P62 protein is associated with neurofibrillary tangles composed primarily of hyperphosphorylated tau protein and ubiquitin. Increasing evidence indicates that P62 has an important role in the degradation of tau protein. The lack of P62 protein expression provokes the tau pathology in mice. Recent studies have demonstrated that the P62 gene expression and cytoplasmic P62 protein levels are significantly reduced in the frontal cortex of AD patients. Decline in the level of P62 protein can disturb the signaling pathways of Nrf2, cyclic AMP and NF-κB and in that way increase oxidative stress and impair neuronal survival. We will review here the molecular and functional characteristics of P62 protein and outline its potential role in the regulation of Alzheimer's pathogenesis.
Jeong Sig Kim - One of the best experts on this subject based on the ideXlab platform.
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sestrin2 promotes unc 51 like kinase 1 mediated phosphorylation of P62 sequestosome 1
FEBS Journal, 2014Co-Authors: Ian A Semple, Hwanwoo Park, Haeli Park, Hae-won Park, Myungjin Kim, Jeong Sig Kim, Jun Hee LeeAbstract:Autophagy is a homeostatic process that is important for degrading protein aggregates, nutrient deposits, dysfunctional organelles and several signaling molecules. P62/sequestosome-1 is a protein that binds to several autophagy substrates, such as ubiquitinated proteins, damaged mitochondria and signaling molecules such as an Nrf2 inhibitor Keap1, promoting their autophagic degradation. Sestrin2, a stress-inducible protein, has been recently shown to bind to P62 and promote autophagic degradation of such P62 targets. Because Sestrin2 is a metabolic regulator that suppresses diverse age- and obesity-associated pathologies, the autophagy-controlling function of Sestrin2 may be important for its other physiological functions. However, the molecular mechanism of how Sestrin2 can promote clearance of P62-associated proteins has been unclear. Here we show that Sestrin2 physically associates with ULK1 and P62 to form a complex, in which both Sestrin2 and P62 become phosphorylated by ULK1 at multiple sites. Ser403 of P62, whose phosphorylation is known to promote autophagic degradation of P62 and its targets, is among the sites phosphorylated by ULK1. ULK1-mediated P62 phosphorylation was facilitated by Sestrin2 in cells as well as in vitro kinase assays. Consistent with this finding, oligomycin-induced energy deprivation, which strongly activates ULK1, provoked a robust Ser403 phosphorylation of P62 in wild-type (WT) mouse embryonic fibroblasts (MEF). However, in ULK1/2- and Sestrin2-deficient MEF, oligomycin-induced P62 phosphorylation was dramatically attenuated, suggesting that endogenous Sestrin2-ULK1/2 mainly mediates P62 phosphorylation in response to energetic stress. Taken together, this study identifies ULK1 as a new P62 Ser403 kinase and establishes Sestrin2 as a promoter of ULK1-mediated P62 phosphorylation.
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Sestrin2 promotes Unc-51-like kinase 1 mediated phosphorylation of P62/sequestosome-1
FEBS Journal, 2014Co-Authors: Ian A Semple, Hwanwoo Park, Haeli Park, Hae-won Park, Myungjin Kim, Jeong Sig Kim, Jun Hee LeeAbstract:Autophagy is a homeostatic process that is important for degrading protein aggregates, nutrient deposits, dysfunctional organelles and several signaling molecules. P62/sequestosome-1 is a protein that binds to several autophagy substrates, such as ubiquitinated proteins, damaged mitochondria and signaling molecules such as an Nrf2 inhibitor Keap1, promoting their autophagic degradation. Sestrin2, a stress-inducible protein, has been recently shown to bind to P62 and promote autophagic degradation of such P62 targets. Because Sestrin2 is a metabolic regulator that suppresses diverse age- and obesity-associated pathologies, the autophagy-controlling function of Sestrin2 may be important for its other physiological functions. However, the molecular mechanism of how Sestrin2 can promote clearance of P62-associated proteins has been unclear. Here we show that Sestrin2 physically associates with ULK1 and P62 to form a complex, in which both Sestrin2 and P62 become phosphorylated by ULK1 at multiple sites. Ser403 of P62, whose phosphorylation is known to promote autophagic degradation of P62 and its targets, is among the sites phosphorylated by ULK1. ULK1-mediated P62 phosphorylation was facilitated by Sestrin2 in cells as well as in vitro kinase assays. Consistent with this finding, oligomycin-induced energy deprivation, which strongly activates ULK1, provoked a robust Ser403 phosphorylation of P62 in wild-type (WT) mouse embryonic fibroblasts (MEF). However, in ULK1/2- and Sestrin2-deficient MEF, oligomycin-induced P62 phosphorylation was dramatically attenuated, suggesting that endogenous Sestrin2-ULK1/2 mainly mediates P62 phosphorylation in response to energetic stress. Taken together, this study identifies ULK1 as a new P62 Ser403 kinase and establishes Sestrin2 as a promoter of ULK1-mediated P62 phosphorylation.
Yoshinobu Ichimura - One of the best experts on this subject based on the ideXlab platform.
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P62 sqstm1 promotes malignancy of hcv positive hepatocellular carcinoma through nrf2 dependent metabolic reprogramming
Nature Communications, 2016Co-Authors: Tetsuya Saito, Yoshinobu Ichimura, Tsunehiro Mizushima, Keiko Taguchi, Takafumi Suzuki, Kenji Takagi, Yuki Hirose, Masayuki Nagahashi, Tetsuro IsoAbstract:P62/Sqstm1 is a multifunctional protein involved in cell survival, growth and death, that is degraded by autophagy. Amplification of the P62/Sqstm1 gene, and aberrant accumulation and phosphorylation of P62/Sqstm1, have been implicated in tumour development. Herein, we reveal the molecular mechanism of P62/Sqstm1-dependent malignant progression, and suggest that molecular targeting of P62/Sqstm1 represents a potential chemotherapeutic approach against hepatocellular carcinoma (HCC). Phosphorylation of P62/Sqstm1 at Ser349 directs glucose to the glucuronate pathway, and glutamine towards glutathione synthesis through activation of the transcription factor Nrf2. These changes provide HCC cells with tolerance to anti-cancer drugs and proliferation potency. Phosphorylated P62/Sqstm1 accumulates in tumour regions positive for hepatitis C virus (HCV). An inhibitor of phosphorylated P62-dependent Nrf2 activation suppresses the proliferation and anticancer agent tolerance of HCC. Our data indicate that this Nrf2 inhibitor could be used to make cancer cells less resistant to anticancer drugs, especially in HCV-positive HCC patients.
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P62 sqstm1 a170 physiology and pathology
Pharmacological Research, 2012Co-Authors: Masaaki Komatsu, Shun Kageyama, Yoshinobu IchimuraAbstract:P62/SQSTM1/A170 (hereafter referred to as P62) is a stress-inducible intracellular protein known to regulate various signal transduction pathways involved in cell survival and cell death. Comprehensive analysis of LC3 (an autophagosome localizing protein)-binding proteins resulted in the recognition of autophagy and P62. While autophagy modulates the level of P62 protein, P62 can suppress autophagy via activation of mTORC1. Moreover, growing lines of evidence point to the important role of P62 in directing ubiquitinated cargos toward autophagy as well as compaction of those cargos. Furthermore, this protein functions as a signaling hub for various signal transduction pathways, such as NF-κB signaling, apoptosis, and Nrf2 activation, whose dysregulation is associated with Paget disease of bone and tumorigenesis. In this review, we discuss the pathophysiological significance of P62 and its role in autophagy.
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P62/SQSTM1/A170: Physiology and pathology
Pharmacological research, 2012Co-Authors: Masaaki Komatsu, Shun Kageyama, Yoshinobu IchimuraAbstract:P62/SQSTM1/A170 (hereafter referred to as P62) is a stress-inducible intracellular protein known to regulate various signal transduction pathways involved in cell survival and cell death. Comprehensive analysis of LC3 (an autophagosome localizing protein)-binding proteins resulted in the recognition of autophagy and P62. While autophagy modulates the level of P62 protein, P62 can suppress autophagy via activation of mTORC1. Moreover, growing lines of evidence point to the important role of P62 in directing ubiquitinated cargos toward autophagy as well as compaction of those cargos. Furthermore, this protein functions as a signaling hub for various signal transduction pathways, such as NF-κB signaling, apoptosis, and Nrf2 activation, whose dysregulation is associated with Paget disease of bone and tumorigenesis. In this review, we discuss the pathophysiological significance of P62 and its role in autophagy.
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structural basis for sorting mechanism of P62 in selective autophagy
Journal of Biological Chemistry, 2008Co-Authors: Yoshinobu Ichimura, Taichi Kumanomidou, Tsunehiro Mizushima, Junji Ezaki, Takashi Ueno, Eiki Kominami, Takashi Yamane, Keiji Tanaka, Masaaki KomatsuAbstract:Abstract Impairment of autophagic degradation of the ubiquitin- and LC3-binding protein “P62” leads to the formation of cytoplasmic inclusion bodies. However, little is known about the sorting mechanism of P62 to autophagic degradation. Here we identified a motif of murine P62 consisting of 11 amino acids (Ser334-Ser344) containing conserved acidic and hydrophobic residues across species, as an LC3 recognition sequence (LRS). The crystal structure of the LC3-LRS complex at 1.56A resolution revealed interaction of Trp340 and Leu343 of P62 with different hydrophobic pockets on the ubiquitin fold of LC3. In vivo analyses demonstrated that P62 mutants lacking LC3 binding ability accumulated without entrapping into autophagosomes in the cytoplasm and subsequently formed ubiquitin-positive inclusion bodies as in autophagy-deficient cells. These results demonstrate that the intracellular level of P62 is tightly regulated by autophagy through the direct interaction of LC3 with P62 and reveal that selective turnover of P62 via autophagy controls inclusion body formation.
Ian A Semple - One of the best experts on this subject based on the ideXlab platform.
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sestrin2 promotes unc 51 like kinase 1 mediated phosphorylation of P62 sequestosome 1
FEBS Journal, 2014Co-Authors: Ian A Semple, Hwanwoo Park, Haeli Park, Hae-won Park, Myungjin Kim, Jeong Sig Kim, Jun Hee LeeAbstract:Autophagy is a homeostatic process that is important for degrading protein aggregates, nutrient deposits, dysfunctional organelles and several signaling molecules. P62/sequestosome-1 is a protein that binds to several autophagy substrates, such as ubiquitinated proteins, damaged mitochondria and signaling molecules such as an Nrf2 inhibitor Keap1, promoting their autophagic degradation. Sestrin2, a stress-inducible protein, has been recently shown to bind to P62 and promote autophagic degradation of such P62 targets. Because Sestrin2 is a metabolic regulator that suppresses diverse age- and obesity-associated pathologies, the autophagy-controlling function of Sestrin2 may be important for its other physiological functions. However, the molecular mechanism of how Sestrin2 can promote clearance of P62-associated proteins has been unclear. Here we show that Sestrin2 physically associates with ULK1 and P62 to form a complex, in which both Sestrin2 and P62 become phosphorylated by ULK1 at multiple sites. Ser403 of P62, whose phosphorylation is known to promote autophagic degradation of P62 and its targets, is among the sites phosphorylated by ULK1. ULK1-mediated P62 phosphorylation was facilitated by Sestrin2 in cells as well as in vitro kinase assays. Consistent with this finding, oligomycin-induced energy deprivation, which strongly activates ULK1, provoked a robust Ser403 phosphorylation of P62 in wild-type (WT) mouse embryonic fibroblasts (MEF). However, in ULK1/2- and Sestrin2-deficient MEF, oligomycin-induced P62 phosphorylation was dramatically attenuated, suggesting that endogenous Sestrin2-ULK1/2 mainly mediates P62 phosphorylation in response to energetic stress. Taken together, this study identifies ULK1 as a new P62 Ser403 kinase and establishes Sestrin2 as a promoter of ULK1-mediated P62 phosphorylation.
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Sestrin2 promotes Unc-51-like kinase 1 mediated phosphorylation of P62/sequestosome-1
FEBS Journal, 2014Co-Authors: Ian A Semple, Hwanwoo Park, Haeli Park, Hae-won Park, Myungjin Kim, Jeong Sig Kim, Jun Hee LeeAbstract:Autophagy is a homeostatic process that is important for degrading protein aggregates, nutrient deposits, dysfunctional organelles and several signaling molecules. P62/sequestosome-1 is a protein that binds to several autophagy substrates, such as ubiquitinated proteins, damaged mitochondria and signaling molecules such as an Nrf2 inhibitor Keap1, promoting their autophagic degradation. Sestrin2, a stress-inducible protein, has been recently shown to bind to P62 and promote autophagic degradation of such P62 targets. Because Sestrin2 is a metabolic regulator that suppresses diverse age- and obesity-associated pathologies, the autophagy-controlling function of Sestrin2 may be important for its other physiological functions. However, the molecular mechanism of how Sestrin2 can promote clearance of P62-associated proteins has been unclear. Here we show that Sestrin2 physically associates with ULK1 and P62 to form a complex, in which both Sestrin2 and P62 become phosphorylated by ULK1 at multiple sites. Ser403 of P62, whose phosphorylation is known to promote autophagic degradation of P62 and its targets, is among the sites phosphorylated by ULK1. ULK1-mediated P62 phosphorylation was facilitated by Sestrin2 in cells as well as in vitro kinase assays. Consistent with this finding, oligomycin-induced energy deprivation, which strongly activates ULK1, provoked a robust Ser403 phosphorylation of P62 in wild-type (WT) mouse embryonic fibroblasts (MEF). However, in ULK1/2- and Sestrin2-deficient MEF, oligomycin-induced P62 phosphorylation was dramatically attenuated, suggesting that endogenous Sestrin2-ULK1/2 mainly mediates P62 phosphorylation in response to energetic stress. Taken together, this study identifies ULK1 as a new P62 Ser403 kinase and establishes Sestrin2 as a promoter of ULK1-mediated P62 phosphorylation.
