scholarly journals Glycogen Synthase Kinase-3 Regulates Production of Amyloid-βPeptides and Tau Phosphorylation in Diabetic Rat Brain

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Zhong-Sen Qu ◽  
Liang Li ◽  
Xiao-Jiang Sun ◽  
Yu-Wu Zhao ◽  
Jin Zhang ◽  
...  
Keyword(s):  
Rat Brain ◽  
Glycogen Synthase ◽  
Selective Inhibition ◽  
Neurological Complications ◽  
Glycogen Synthase Kinase ◽  
Glycogen Synthase Kinase 3 ◽  
Diabetic Rat ◽  
Protein Tau ◽  
Microtubule Associated Protein Tau ◽  
Amyloid Deposits

The pathogenesis of diabetic neurological complications is not fully understood. Diabetes mellitus (DM) and Alzheimer’s disease (AD) are characterized by amyloid deposits. Glycogen synthase kinase-3 (GSK-3) plays an important role in the pathogenesis of AD and DM. Here we tried to investigate the production of amyloid-βpeptides (Aβ) and phosphorylation of microtubule-associated protein tau in DM rats and elucidate the role of GSK-3 and Akt (protein kinase B, PKB) in these processes. Streptozotocin injection-induced DM rats displayed an increased GSK-3 activity, decreased activity and expression of Akt. And Aβ40 and Aβ42 were found overproduced and the microtubule-associated protein tau was hyperphosphorylated in the hippocampus. Furthermore, selective inhibition of GSK-3 by lithium could attenuate the conditions of Aβoverproduction and tau hyperphosphorylation. Taken together, our studies suggest that GSK-3 regulates both the production of Aβand the phosphorylation of tau in rat brain and may therefore contribute to DM caused AD-like neurological defects.

scholarly journals The kinase DYRK phosphorylates protein-synthesis initiation factor eIF2Bɛ at Ser539 and the microtubule-associated protein tau at Thr212: potential role for DYRK as a glycogen synthase kinase 3-priming kinase

2001 ◽  
Vol 355 (3) ◽  
pp. 609-615 ◽  
Author(s):  
Yvonne L. WOODS ◽  
Philip COHEN ◽  
Walter BECKER ◽  
Ross JAKES ◽  
Michel GOEDERT ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Protein Kinases ◽  
Glycogen Synthase ◽  
Glycogen Synthase Kinase ◽  
Initiation Factor ◽  
Glycogen Synthase Kinase 3 ◽  
General Role ◽  
Protein Tau ◽  
Microtubule Associated Protein Tau ◽  
Protein Synthesis Initiation

The substrate specificity of glycogen synthase kinase 3 (GSK3) is unusual in that efficient phosphorylation only occurs if another phosphoserine or phosphothreonine residue is already present four residues C-terminal to the site of GSK3 phosphorylation. One such substrate is the ε-subunit of rat eukaryotic protein-synthesis initiation factor 2B (eIF2Bε), which is inhibited by the GSK3-catalysed phosphorylation of Ser535. There is evidence that GSK3 is only able to phosphorylate eIF2Bε at Ser535 if Ser539 is already phosphorylated by another protein kinase. However, no protein kinases capable of phosphorylating Ser539 have so far been identified. Here we show that Ser539 of eIF2Bε, which is followed by proline, is phosphorylated specifically by two isoforms of dual-specificity tyrosine phosphorylated and regulated kinase (DYRK2 and DYRK1A), but only weakly or not at all by other ‘proline-directed’ protein kinases tested. We also establish that phosphorylation of Ser539 permits GSK3 to phosphorylate Ser535in vitro and that eIF2Bε is highly phosphorylated at Ser539in vivo. The DYRK isoforms also phosphorylate human microtubule-associated protein tau at Thr212in vitro, a residue that is phosphorylated in foetal tau and hyperphosphorylated in filamentous tau from Alzheimer's-disease brain. Phosphorylation of Thr212 primes tau for phosphorylation by GSK3 at Ser208in vitro, suggesting a more general role for DYRK isoforms in priming phosphorylation of GSK3 substrates.

scholarly journals Glycogen synthase kinase-3 and the Alzheimer-like state of microtubule-associated protein tau

FEBS Letters ◽  
1992 ◽  
Vol 314 (3) ◽  
pp. 315-321 ◽  
Author(s):  
E.-M. Mandelkow ◽  
G. Drewes ◽  
J. Biernat ◽  
N. Gustke ◽  
J. Van Lint ◽  
...  
Keyword(s):  
Glycogen Synthase ◽  
Glycogen Synthase Kinase ◽  
Glycogen Synthase Kinase 3 ◽  
Protein Tau ◽  
Microtubule Associated Protein Tau

scholarly journals Identification of a novel selective and potent inhibitor of glycogen synthase kinase-3

2019 ◽  
Vol 317 (6) ◽  
pp. C1289-C1303 ◽  
Author(s):  
Mahboubeh S. Noori ◽  
Pooja M. Bhatt ◽  
Maria C. Courreges ◽  
Davoud Ghazanfari ◽  
Chaz Cuckler ◽  
...  
Keyword(s):  
Design Space ◽  
Potent Inhibitor ◽  
Glycogen Synthase ◽  
Selective Inhibition ◽  
Glycogen Synthase Kinase ◽  
Glycogen Synthase Kinase 3 ◽  
Cellular Functions ◽  
Starting Point ◽  
Potential Therapeutics

Glycogen synthase kinase-3 (GSK-3) is a multitasking protein kinase that regulates numerous critical cellular functions. Not surprisingly, elevated GSK-3 activity has been implicated in a host of diseases including pathological inflammation, diabetes, cancer, arthritis, asthma, bipolar disorder, and Alzheimer’s. Therefore, reagents that inhibit GSK-3 activity provide a means to investigate the role of GSK-3 in cellular physiology and pathophysiology and could become valuable therapeutics. Finding a potent inhibitor of GSK-3 that can selectively target this kinase, among over 500 protein kinases in the human genome, is a significant challenge. Thus there remains a critical need for the identification of selective inhibitors of GSK-3. In this work, we introduce a novel small organic compound, namely COB-187, which exhibits potent and highly selective inhibition of GSK-3. Specifically, this study 1) utilized a molecular screen of 414 kinase assays, representing 404 unique kinases, to reveal that COB-187 is a highly potent and selective inhibitor of GSK-3; 2) utilized a cellular assay to reveal that COB-187 decreases the phosphorylation of canonical GSK-3 substrates indicating that COB-187 inhibits cellular GSK-3 activity; and 3) reveals that a close isomer of COB-187 is also a selective and potent inhibitor of GSK-3. Taken together, these results demonstrate that we have discovered a region of chemical design space that contains novel GSK-3 inhibitors. These inhibitors will help to elucidate the intricate function of GSK-3 and can serve as a starting point for the development of potential therapeutics for diseases that involve aberrant GSK-3 activity.

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