title: IKKbeta programs to turn on the GADD45alpha-MKK4-JNK apoptotic cascade specifically via p50 NF-kappaB in arsenite response.
abstract: Cross talk between NF-kappaB and c-Jun N-terminal kinases (JNKs) has been implicated in the cell life and death decision under various stresses. Functional suppression of JNK activation by NF-kappaB has recently been proposed as a key cellular survival mechanism and contributes to cancer cells escaping from apoptosis. We provide a novel scenario of the proapoptotic role of IkappaB kinase beta (IKKbeta)-NF-kappaB, which can act as the activator of the JNK pathway through the induction of GADD45alpha for triggering MKK4/JNK activation, in response to the stimulation of arsenite, a cancer therapeutic reagent. This effect of IKKbeta-NF-kappaB is dependent on p50 but not the p65/relA NF-kappaB subunit, which can increase the stability of GADD45alpha protein through suppressing its ubiquitination and proteasome-dependent degradation. IKKbeta-NF-kappaB can therefore either activate or suppress the JNK cascade and consequently mediate pro- or antiapoptotic effects, depending on the manner of its induction. Furthermore, the NF-kappaB p50 subunit can exert a novel regulatory function on protein modification independent of the classical NF-kappaB transcriptional activity.
authors.affiliation: Nelson Institute of Environmental Medicine, New York University School of Medicine, Tuxedo, NY 10987, USA.
authors.forename: Lun
authors.initials: L
authors.lastname: Song
authors.forename: Jingxia
authors.initials: J
authors.lastname: Li
authors.forename: Dongyun
authors.initials: D
authors.lastname: Zhang
authors.forename: Zheng-Gang
authors.initials: ZG
authors.lastname: Liu
authors.forename: Jianping
authors.initials: J
authors.lastname: Ye
authors.forename: Qimin
authors.initials: Q
authors.lastname: Zhan
authors.forename: Han-Ming
authors.initials: HM
authors.lastname: Shen
authors.forename: Matt
authors.initials: M
authors.lastname: Whiteman
authors.forename: Chuanshu
authors.initials: C
authors.lastname: Huang
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D018053:Arsenites / Q000494:pharmacology*; D018797:Cell Cycle Proteins / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects; D051550:I-kappa B Kinase / Q000172:deficiency / Q000378:metabolism*; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism*; D048670:MAP Kinase Kinase 4 / Q000378:metabolism*; D051379:Mice; D052002:NF-kappa B p50 Subunit / Q000172:deficiency / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D046988:Proteasome Endopeptidase Complex / Q000187:drug effects; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects; D051996:Transcription Factor RelA / Q000378:metabolism; D025801:Ubiquitin / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects; D000097642:GADD45 Proteins
chemical_list: D018053:Arsenites; D018797:Cell Cycle Proteins; D051550:I-kappa B Kinase; D048031:JNK Mitogen-Activated Protein Kinases; D048670:MAP Kinase Kinase 4; D052002:NF-kappa B p50 Subunit; D009687:Nuclear Proteins; D046988:Proteasome Endopeptidase Complex; D051996:Transcription Factor RelA; D025801:Ubiquitin; C499072:Gadd45a protein, mouse; D000097642:GADD45 Proteins; C015001:arsenite