title: Cleavage of GSK-3β by calpain counteracts the inhibitory effect of Ser9 phosphorylation on GSK-3β activity induced by H₂O₂.
abstract: Glycogen synthase kinase-3 beta (GSK-3β) dysfunction may play an essential role in the pathogenesis of psychiatric, metabolic, neurodegenerative diseases, in which oxidative stress exists concurrently. Some studies have shown that GSK-3β activity is up-regulated under oxidative stress. This study evaluated how oxidative stress regulates GSK-3β activity in human embryonic kidney 293 (HEK293)/Tau cells treated with hydrogen peroxide (H₂O₂). Here, we show that H₂O₂ induced an obvious increase of GSK-3β activity. Surprisingly, H₂O₂ dramatically increased phosphorylation of GSK-3β at Ser9, an inactive form of GSK-3β,while there were no changes of phosphorylation of GSK-3β at Tyr216. Moreover, H₂O₂ led to a transient [Ca²⁺](i) elevation, and simultaneously increased the truncation of GSK-3β into two fragments of 40 kDa and 30 kDa, whereas inhibition of calpain decreased the truncation and recovered the activity of GSK-3β. Furthermore, tau was hyperphosphorylated at Ser396, Ser404, and Thr231, three most common GSK-3β targeted sites after 100 μM H₂O₂ administration in HEK293/Tau cells, whereas inhibition of calpain blocked the tau phosphorylation. In addition, we found that there were no obvious changes of Cyclin-dependent kinase 5 (CDK5) expression (responsible for tau phosphorylation) and of p35 cleavage, the regulatory subunit of CDK5 in H₂O₂-treated HEK293/Tau cells. In conclusion, Ca²⁺-dependent calpain activation leads to GSK-3β truncation, which counteracts the inhibitory effect of Ser9 phosphorylation, up-regulates GSK-3β activity, and phosphorylates tau in H₂O₂-treated HEK293/Tau cells.
authors: Department of Pathophysiology, Key Laboratory of Neurological Disease of National Education Ministry, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors: Ye
authors: Y
authors: Feng
authors: Yiyuan
authors: Y
authors: Xia
authors: Guang
authors: G
authors: Yu
authors: Xiji
authors: X
authors: Shu
authors: Haoliang
authors: H
authors: Ge
authors: Kuan
authors: K
authors: Zeng
authors: Jianzhi
authors: J
authors: Wang
authors: Xiaochuan
authors: X
authors: Wang
mesh_terms: D002118:Calcium / Q000378:metabolism; D002154:Calpain / Q000494:pharmacology*; D002470:Cell Survival / Q000187:drug effects / Q000235:genetics; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D038362:Glycogen Synthase Kinase 3 / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D000071679:Glycogen Synthase Kinase 3 beta; D006023:Glycoproteins / Q000494:pharmacology; D057809:HEK293 Cells; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D007424:Intracellular Fluid / Q000187:drug effects / Q000378:metabolism; D008315:Malondialdehyde / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D051058:Oncogene Protein v-akt / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects; D010766:Phosphorylation / Q000187:drug effects; D012694:Serine / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D013482:Superoxide Dismutase / Q000378:metabolism; D014162:Transfection; D015854:Up-Regulation / Q000187:drug effects*; D016875:tau Proteins / Q000235:genetics
chemical_list: D004791:Enzyme Inhibitors; D006023:Glycoproteins; C039304:calpain inhibitors; D016875:tau Proteins; D012694:Serine; D008315:Malondialdehyde; D006861:Hydrogen Peroxide; D013482:Superoxide Dismutase; C000605506:GSK3B protein, human; D000071679:Glycogen Synthase Kinase 3 beta; D051058:Oncogene Protein v-akt; D038362:Glycogen Synthase Kinase 3; D002154:Calpain; D002118:Calcium
keywords: GSK-3β; HEK293/Tau cells; calpain; hydrogen peroxide (H2O2)