p(HGNC:SQSTM1)
Reduced levels of lipofuscin, LC3, and p62 have been observed in motor neurons of SOD1(G85R) mice (92). Treatment with the autophagy inhibitor chloroquine restored lipofuscin, LC3, and p62 levels in motor neurons, suggesting that mutant SOD1 causes hyperactive autophagy in mice (92). PubMed:25784053
Reduced levels of lipofuscin, LC3, and p62 have been observed in motor neurons of SOD1(G85R) mice (92). Treatment with the autophagy inhibitor chloroquine restored lipofuscin, LC3, and p62 levels in motor neurons, suggesting that mutant SOD1 causes hyperactive autophagy in mice (92). PubMed:25784053
ALS shares many causal genes with FTD, including SQSTM1, CHMP2B, TBK1 (which encodes tank-binding kinase 1), OPTN (which encodes optineurin) and other genes associated with deficits in ALN and mitophagy. PubMed:30116051
However, in light of common risk genes such as SQSTM1 (which encodes p62) and chromosome 9 open reading frame 72 (C9ORF72), FTD is increasingly linked to ALS 82,83 . PubMed:30116051
Epigallocatechin-3-gallate enhances the clearance of ADrelevant phosphorylated tau species via increasing mRNA expression of autophagy adaptor proteins NDP52 and p62 (Chesser et al. 2016) PubMed:29626319
SQSTM1, induced 20-fold, encodes sequestosome-1, a participant in the autophagy pathway recently shown to be necessary to avoid premature senescence in human fibroblasts (Kang et al., 2011). PubMed:22020111
Methylene blue, a contrast agent that can reduce tau misfolding, has also been shown to induce macroautophagy, as indicated by elevated Beclin 1 and LC3-II levels and reduced tau and p62 levels in organotypic neuronal cultures and a mouse model of FTD [159] PubMed:29758300
In APP transgenic mouse models of AD, undigested autophagy substrates including LC3-II, p62, and ubiquitinated proteins accumulate in neuronal AVs, establishing that autophagic protein turnover in lysosomes is impeded (Yang et al. 2011). PubMed:22908190
For example, p62, an adaptor protein for autophagy, also influences proteasomal degradation, whereas VCP/p97 acting through p62 and ubiquitin regulates both the proteasome-dependent endoplasmic reticulum–associated degradation (ERAD) pathway and aspects of autophagosome maturation (Tresse et al. 2010). PubMed:22908190
p62 localizes to a variety of ubiquitin-positive neuropathological inclusions including Lewy bodies in Parkinson’s disease, neurofibrillary tangles in tauopathies, polyglutamine-expanded huntingtin aggregates in Huntington’s disease, and aggregates of mutant SOD1 in familial amyotrophic lateral sclerosis [85–87]. PubMed:18930136
p62 localizes to a variety of ubiquitin-positive neuropathological inclusions including Lewy bodies in Parkinson’s disease, neurofibrillary tangles in tauopathies, polyglutamine-expanded huntingtin aggregates in Huntington’s disease, and aggregates of mutant SOD1 in familial amyotrophic lateral sclerosis [85–87]. PubMed:18930136
Cellular stresses such as polyQ expression, proteasome impairment, oxidative stress, and increased misfolded protein burden activate transcription and translation of p62, suggesting that it functions broadly in stress situations [83,84] PubMed:18930136
Specifically, it is suggested that K63-linked polyubiquitin chains recruit p62 and HDAC6 providing a signal for autophagic degradation [92,93]. PubMed:18930136
Cellular stresses such as polyQ expression, proteasome impairment, oxidative stress, and increased misfolded protein burden activate transcription and translation of p62, suggesting that it functions broadly in stress situations [83,84] PubMed:18930136
Cellular stresses such as polyQ expression, proteasome impairment, oxidative stress, and increased misfolded protein burden activate transcription and translation of p62, suggesting that it functions broadly in stress situations [83,84] PubMed:18930136
p62 localizes to a variety of ubiquitin-positive neuropathological inclusions including Lewy bodies in Parkinson’s disease, neurofibrillary tangles in tauopathies, polyglutamine-expanded huntingtin aggregates in Huntington’s disease, and aggregates of mutant SOD1 in familial amyotrophic lateral sclerosis [85–87]. PubMed:18930136
Cellular stresses such as polyQ expression, proteasome impairment, oxidative stress, and increased misfolded protein burden activate transcription and translation of p62, suggesting that it functions broadly in stress situations [83,84] PubMed:18930136
Compared with the MAPT-free dendrites of control neurons (Fig. S4A, 1.8±0.1), a substantial increase of SQSTM1 level (21.1±0.9) was observed in MAPT-containing dendrites upon wortmannin treatment (Fig. S4B). PubMed:30145931
However, in light of common risk genes such as SQSTM1 (which encodes p62) and chromosome 9 open reading frame 72 (C9ORF72), FTD is increasingly linked to ALS 82,83 . PubMed:30116051
ALS shares many causal genes with FTD, including SQSTM1, CHMP2B, TBK1 (which encodes tank-binding kinase 1), OPTN (which encodes optineurin) and other genes associated with deficits in ALN and mitophagy. PubMed:30116051
SQSTM1, induced 20-fold, encodes sequestosome-1, a participant in the autophagy pathway recently shown to be necessary to avoid premature senescence in human fibroblasts (Kang et al., 2011). PubMed:22020111
SQSTM1, induced 20-fold, encodes sequestosome-1, a participant in the autophagy pathway recently shown to be necessary to avoid premature senescence in human fibroblasts (Kang et al., 2011). PubMed:22020111
Evidence that p62 facilitates tau degradation has been demonstrated in several studies where p62 colocalized with tau in NFTs from AD patients [53]. PubMed:29758300
For example, Babu et al. has shown that p62−/− knockout mice have increased levels of hyperphosphorylated tau, reduction of synaptophysin and changes in short term memory compared to p62+/− [54] PubMed:29758300
For example, Babu et al. has shown that p62−/− knockout mice have increased levels of hyperphosphorylated tau, reduction of synaptophysin and changes in short term memory compared to p62+/− [54] PubMed:29758300
For example, Babu et al. has shown that p62−/− knockout mice have increased levels of hyperphosphorylated tau, reduction of synaptophysin and changes in short term memory compared to p62+/− [54] PubMed:29758300
For example, p62, an adaptor protein for autophagy, also influences proteasomal degradation, whereas VCP/p97 acting through p62 and ubiquitin regulates both the proteasome-dependent endoplasmic reticulum–associated degradation (ERAD) pathway and aspects of autophagosome maturation (Tresse et al. 2010). PubMed:22908190
For example, p62, an adaptor protein for autophagy, also influences proteasomal degradation, whereas VCP/p97 acting through p62 and ubiquitin regulates both the proteasome-dependent endoplasmic reticulum–associated degradation (ERAD) pathway and aspects of autophagosome maturation (Tresse et al. 2010). PubMed:22908190
Although the mechanism whereby autophagy and UPS function are coordinated is little understood, several regulators have emerged as important players in mediating this crosstalk, including histone deacetylase 6 (HDAC6) [50,64,75], p62/sequestosome 1 (p62) [76], and the FYVE-domain containing protein Alfy [77]; notably, these proteins have all been found to regulate or be essential for aggresome formation PubMed:18930136
Thus, it has been suggested that p62 provides a key link between autophagy and the UPS by facilitating autophagic degradation of ubiquitinated proteins. PubMed:18930136
Recent models propose that p62 and HDAC6 function analogously to facilitate autophagic degradation of proteins that display specific polyubiquitin topology. PubMed:18930136
Although the mechanism whereby autophagy and UPS function are coordinated is little understood, several regulators have emerged as important players in mediating this crosstalk, including histone deacetylase 6 (HDAC6) [50,64,75], p62/sequestosome 1 (p62) [76], and the FYVE-domain containing protein Alfy [77]; notably, these proteins have all been found to regulate or be essential for aggresome formation PubMed:18930136
Thus, it has been suggested that p62 provides a key link between autophagy and the UPS by facilitating autophagic degradation of ubiquitinated proteins. PubMed:18930136
Although the mechanism whereby autophagy and UPS function are coordinated is little understood, several regulators have emerged as important players in mediating this crosstalk, including histone deacetylase 6 (HDAC6) [50,64,75], p62/sequestosome 1 (p62) [76], and the FYVE-domain containing protein Alfy [77]; notably, these proteins have all been found to regulate or be essential for aggresome formation PubMed:18930136
p62 localizes to a variety of ubiquitin-positive neuropathological inclusions including Lewy bodies in Parkinson’s disease, neurofibrillary tangles in tauopathies, polyglutamine-expanded huntingtin aggregates in Huntington’s disease, and aggregates of mutant SOD1 in familial amyotrophic lateral sclerosis [85–87]. PubMed:18930136
p62 localizes to a variety of ubiquitin-positive neuropathological inclusions including Lewy bodies in Parkinson’s disease, neurofibrillary tangles in tauopathies, polyglutamine-expanded huntingtin aggregates in Huntington’s disease, and aggregates of mutant SOD1 in familial amyotrophic lateral sclerosis [85–87]. PubMed:18930136
p62 localizes to a variety of ubiquitin-positive neuropathological inclusions including Lewy bodies in Parkinson’s disease, neurofibrillary tangles in tauopathies, polyglutamine-expanded huntingtin aggregates in Huntington’s disease, and aggregates of mutant SOD1 in familial amyotrophic lateral sclerosis [85–87]. PubMed:18930136
Thus, it has been suggested that p62 provides a key link between autophagy and the UPS by facilitating autophagic degradation of ubiquitinated proteins. PubMed:18930136
Recent models propose that p62 and HDAC6 function analogously to facilitate autophagic degradation of proteins that display specific polyubiquitin topology. PubMed:18930136
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If you find BEL Commons useful in your work, please consider citing: Hoyt, C. T., Domingo-Fernández, D., & Hofmann-Apitius, M. (2018). BEL Commons: an environment for exploration and analysis of networks encoded in Biological Expression Language. Database, 2018(3), 1–11.