p(HGNC:PPP2CA)
The isoform C α is predominantly expressed in the plasma membrane and C β in the cytoplasm and nucleus. PubMed:23454242
ABaC binds directly to MTs through a site that encompasses its catalytic subunit and is distinct from its binding site for tau, and ABaC and tau bind to different domains on MTs. PubMed:10464280
Kynurenic pathway is overactive in AD. QA is co-localized with hyperphosphorylated tau within cortical neurons in AD brain. In primary cultures of human neurons, QA treatment increased tau phosphorylation at serine 199/202, threonine 231 and serine 396/404 in a dose dependent manner. This increase in tau phosphorylation was paralleled by a substantial decrease in the total protein phosphatase activity, mostly in PP2A expression and modest in PP1. PubMed:19623258
Here we show that resveratrol treatment directly interferes with the MID1-α4-PP2A degradation complex by reducing MID1 protein expression in vitro and in vivo. This leads to an increase of microtubule-associated PP2A activity and a time- and dose-dependent dephosphorylation of Tau. Interestingly, we further show that MID1 expression is elevated in AD tissue. PubMed:29062069
Here we show that resveratrol treatment directly interferes with the MID1-α4-PP2A degradation complex by reducing MID1 protein expression in vitro and in vivo. This leads to an increase of microtubule-associated PP2A activity and a time- and dose-dependent dephosphorylation of Tau. Interestingly, we further show that MID1 expression is elevated in AD tissue. PubMed:29062069
Here we show that resveratrol treatment directly interferes with the MID1-α4-PP2A degradation complex by reducing MID1 protein expression in vitro and in vivo. This leads to an increase of microtubule-associated PP2A activity and a time- and dose-dependent dephosphorylation of Tau. Interestingly, we further show that MID1 expression is elevated in AD tissue. PubMed:29062069
Pin1 is indicated to facilitate Tau dephosphorylation via PP2A by binding to the phospho-Thr-231-Pro or phospho-Thr-212-Pro site PubMed:19401603
These findings suggest a scenario in which MC-LR-mediated demethylation of PP2Ac is associated with GSK-3β phosphorylation at Ser9 and contributes to dissociation of Bα from PP2Ac, which would result in Bα degradation and disruption of PP2A/Bα-tau interactions, thus promoting tau hyperphosphorylation and paired helical filaments-tau accumulation and, consequently, axonal degeneration and cell death. PubMed:29228318
Second, conformational flexibility of the scaffold subunit might be important for the phosphatase activity of the catalytic subunit PubMed:19277525
The catalytic subunit of PP2A is the primary cellular target of OA PubMed:19277525
A portion of cellular PP2A stably associated with PME-1 and was catalytically inactive [80]; intriguingly, this inactive portion of PP2A could be re-activated by PP2A phosphatase activator (PTPA), but not by LCMT1, ruling out the possibility that inactivation was solely caused by demethylation PubMed:19277525
Interestingly, although PME-1 is activated by PP2A binding, the catalytic subunit of PP2A is inactivated in this process, not just through demethylation but also by loss of the catalytic metal ions PubMed:19277525
Interestingly, although PME-1 is activated by PP2A binding, the catalytic subunit of PP2A is inactivated in this process, not just through demethylation but also by loss of the catalytic metal ions PubMed:19277525
Deficits in PP2A activity are in line with the reported down-regulation of PP2A catalytic C subunit at the gene (Loring et al.,2001), mRNA (Vogelsberg-Ragaglia et al.,2001) and protein (Sontag et al.,2004b) expression levels in AD. PubMed:24653673
Lastly, increased calpain-mediated cleavage of alpha4, which critically modulates PP2A stability, could be responsible for increased degradation of PP2A catalytic subunit in AD (Watkins et al., 2012). PubMed:24653673
Deficits in PP2A activity are in line with the reported down-regulation of PP2A catalytic C subunit at the gene (Loring et al.,2001), mRNA (Vogelsberg-Ragaglia et al.,2001) and protein (Sontag et al.,2004b) expression levels in AD. PubMed:24653673
Among them, PP2A is the main phosphatase:it accounts for ~70% of the human brain tau phosphatase activity, and its activity is reduced in the AD brain (by ~20% and ~40% in the grey and white matter, respectively) PubMed:26631930
Protein phosphatase 1 (PP1), PP2A, PP2B, PP2C and PP5 have all been implicated in the dephosphorylation of tau PubMed:26631930
Protein phosphatase 2A agonists are reported to activate autophagy by affecting AMPK and mTORC1 signaling pathways (Magnaudeix et al. 2013) PubMed:29626319
ABaC binds directly to MTs through a site that encompasses its catalytic subunit and is distinct from its binding site for tau, and ABaC and tau bind to different domains on MTs. PubMed:10464280
ABaC binds directly to MTs through a site that encompasses its catalytic subunit and is distinct from its binding site for tau, and ABaC and tau bind to different domains on MTs. PubMed:10464280
These findings suggest a scenario in which MC-LR-mediated demethylation of PP2Ac is associated with GSK-3β phosphorylation at Ser9 and contributes to dissociation of Bα from PP2Ac, which would result in Bα degradation and disruption of PP2A/Bα-tau interactions, thus promoting tau hyperphosphorylation and paired helical filaments-tau accumulation and, consequently, axonal degeneration and cell death. PubMed:29228318
Here we show that resveratrol treatment directly interferes with the MID1-α4-PP2A degradation complex by reducing MID1 protein expression in vitro and in vivo. This leads to an increase of microtubule-associated PP2A activity and a time- and dose-dependent dephosphorylation of Tau. Interestingly, we further show that MID1 expression is elevated in AD tissue. PubMed:29062069
Pin1 is indicated to facilitate Tau dephosphorylation via PP2A by binding to the phospho-Thr-231-Pro or phospho-Thr-212-Pro site PubMed:19401603
Pin1 is indicated to facilitate Tau dephosphorylation via PP2A by binding to the phospho-Thr-231-Pro or phospho-Thr-212-Pro site PubMed:19401603
Pin1 is indicated to facilitate Tau dephosphorylation via PP2A by binding to the phospho-Thr-231-Pro or phospho-Thr-212-Pro site PubMed:19401603
The isoform C α is predominantly expressed in the plasma membrane and C β in the cytoplasm and nucleus. PubMed:23454242
Structures of the PP2A core enzyme reveal that the catalytic subunit recognizes one end of the scaffold subunit through interactions with the conserved ridge of HEAT repeats 11–15 PubMed:19277525
Previous studies suggested that carboxy-methylation of the catalytic subunit played an important role in the assembly of heterotrimeric PP2A holoenzymes in cells PubMed:19277525
Deficits in PP2A activity are in line with the reported down-regulation of PP2A catalytic C subunit at the gene (Loring et al.,2001), mRNA (Vogelsberg-Ragaglia et al.,2001) and protein (Sontag et al.,2004b) expression levels in AD. PubMed:24653673
Deficits in PP2A activity are in line with the reported down-regulation of PP2A catalytic C subunit at the gene (Loring et al.,2001), mRNA (Vogelsberg-Ragaglia et al.,2001) and protein (Sontag et al.,2004b) expression levels in AD. PubMed:24653673
Lastly, increased calpain-mediated cleavage of alpha4, which critically modulates PP2A stability, could be responsible for increased degradation of PP2A catalytic subunit in AD (Watkins et al., 2012). PubMed:24653673
Knock-down of PP2A catalytic subunit (Kins et al.,2001) or PP2A B’δ (or PPP2R5D) regulatory subunit (Louis et al.,2011), and expression of the methylation-site L309A C subunit mutant (Schild et al.,2006) all induce AD-like tau phosphorylation in transgenic mice PubMed:24653673
Dephosphorylation of tau is achieved mainly by protein phosphatase (PP)2A, PP2B (calcineurin), and PP-1 (92). PubMed:29191965
Among them, PP2A is the main phosphatase:it accounts for ~70% of the human brain tau phosphatase activity, and its activity is reduced in the AD brain (by ~20% and ~40% in the grey and white matter, respectively) PubMed:26631930
Among them, PP2A is the main phosphatase:it accounts for ~70% of the human brain tau phosphatase activity, and its activity is reduced in the AD brain (by ~20% and ~40% in the grey and white matter, respectively) PubMed:26631930
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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.