title: E3 ubiquitin ligase Mule ubiquitinates Miz1 and is required for TNFalpha-induced JNK activation.
abstract: The zinc finger transcription factor Miz1 is a negative regulator of TNFalpha-induced JNK activation and cell death through inhibition of TRAF2 K63-polyubiquitination in a transcription-independent manner. Upon TNFalpha stimulation, Miz1 undergoes K48-linked polyubiquitination and proteasomal degradation, thereby relieving its inhibition. However, the underling regulatory mechanism is not known. Here, we report that HECT-domain-containing Mule is the E3 ligase that catalyzes TNFalpha-induced Miz1 polyubiquitination. Mule is a Miz1-associated protein and catalyzes its K48-linked polyubiquitination. TNFalpha-induced polyubiquitination and degradation of Miz1 were inhibited by silencing of Mule and were promoted by ectopic expression of Mule. The interaction between Mule and Miz1 was promoted by TNFalpha independently of the pox virus and zinc finger domain of Miz1. Silencing of Mule stabilized Miz1, thereby suppressing TNFalpha-induced JNK activation and cell death. Thus, our study reveals a molecular mechanism by which Mule regulates TNFalpha-induced JNK activation and apoptosis by catalyzing the polyubiquitination of Miz1.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
authors.forename: Yi
authors.initials: Y
authors.lastname: Yang
authors.forename: HanhChi
authors.initials: H
authors.lastname: Do
authors.forename: Xuejun
authors.initials: X
authors.lastname: Tian
authors.forename: Chaozheng
authors.initials: C
authors.lastname: Zhang
authors.forename: Xinyuan
authors.initials: X
authors.lastname: Liu
authors.forename: Laura A
authors.initials: LA
authors.lastname: Dada
authors.forename: Jacob I
authors.initials: JI
authors.lastname: Sznajder
authors.forename: Jing
authors.initials: J
authors.lastname: Liu
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002460:Cell Line; D004789:Enzyme Activation / Q000187:drug effects; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting; D047468:Immunoprecipitation; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects; D050828:Protein Inhibitors of Activated STAT / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*; D054875:Ubiquitination / Q000187:drug effects
chemical_list: D009687:Nuclear Proteins; D050828:Protein Inhibitors of Activated STAT; D014409:Tumor Necrosis Factor-alpha; C485521:Miz1 protein, mouse; D044767:Ubiquitin-Protein Ligases; D048031:JNK Mitogen-Activated Protein Kinases