title: WW domain-containing oxidoreductase promotes neuronal differentiation via negative regulation of glycogen synthase kinase 3β.
abstract: WW domain-containing oxidoreductase (WWOX), a putative tumour suppressor, is suggested to be involved in the hyperphosphorylation of Alzheimer's Tau. Tau is a microtubule-associated protein that has an important role in microtubule assembly and stability. Glycogen synthase kinase 3β (GSK3β) has a vital role in Tau hyperphosphorylation at its microtubule-binding domains. Hyperphosphorylated Tau has a low affinity for microtubules, thus disrupting microtubule stability. Bioinformatics analysis indicated that WWOX contains two potential GSK3β-binding FXXXLI/VXRLE motifs. Immunofluorescence, immunoprecipitation and molecular modelling showed that WWOX interacts physically with GSK3β. We demonstrated biochemically that WWOX can bind directly to GSK3β through its short-chain alcohol dehydrogenase/reductase domain. Moreover, the overexpression of WWOX inhibited GSK3β-stimulated S396 and S404 phosphorylation within the microtubule domains of Tau, indicating that WWOX is involved in regulating GSK3β activity in cells. WWOX repressed GSK3β activity, restored the microtubule assembly activity of Tau and promoted neurite outgrowth in SH-SY5Y cells. Conversely, RNAi-mediated knockdown of WWOX in retinoic acid (RA)-differentiated SH-SY5Y cells inhibited neurite outgrowth. These results suggest that WWOX is likely to be involved in regulating GSK3β activity, reducing the level of phosphorylated Tau, and subsequently promoting neurite outgrowth during neuron differentiation. In summary, our data reveal a novel mechanism by which WWOX promotes neuronal differentiation in response to RA.
authors.affiliation: Institute of Clinical Medicine, National Cheng Kung University Medical College, Tainan, Taiwan.
authors.forename: H-Y
authors.initials: HY
authors.lastname: Wang
authors.forename: L-I
authors.initials: LI
authors.lastname: Juo
authors.forename: Y-T
authors.initials: YT
authors.lastname: Lin
authors.forename: M
authors.initials: M
authors.lastname: Hsiao
authors.forename: J-T
authors.initials: JT
authors.lastname: Lin
authors.forename: C-H
authors.initials: CH
authors.lastname: Tsai
authors.forename: Y-H
authors.initials: YH
authors.lastname: Tzeng
authors.forename: Y-C
authors.initials: YC
authors.lastname: Chuang
authors.forename: N-S
authors.initials: NS
authors.lastname: Chang
authors.forename: C-N
authors.initials: CN
authors.lastname: Yang
authors.forename: P-J
authors.initials: PJ
authors.lastname: Lu
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001665:Binding Sites; D045744:Cell Line, Tumor; D038362:Glycogen Synthase Kinase 3 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D000071679:Glycogen Synthase Kinase 3 beta; D006801:Humans; D008870:Microtubules / Q000378:metabolism; D056004:Molecular Dynamics Simulation; D008969:Molecular Sequence Data; D055495:Neurogenesis / Q000187:drug effects*; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D010088:Oxidoreductases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D014212:Tretinoin / Q000494:pharmacology; D025521:Tumor Suppressor Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*; D000074584:WW Domain-Containing Oxidoreductase; D016875:tau Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism
chemical_list: D034741:RNA, Small Interfering; D025521:Tumor Suppressor Proteins; D016875:tau Proteins; D014212:Tretinoin; D010088:Oxidoreductases; D000074584:WW Domain-Containing Oxidoreductase; C486071:WWOX protein, human; C000605506:GSK3B protein, human; D000071679:Glycogen Synthase Kinase 3 beta; D038362:Glycogen Synthase Kinase 3