title: Stress-induced nuclear import of apoptosis signal-regulating kinase 1 is mediated by karyopherin α2/β1 heterodimer.
abstract: The apoptosis signal-regulating kinase 1 (ASK1) is activated in response to a wide variety of extracellular stressors. Consequently, dysregulation of ASK1 is associated with multiple pathologies. Here, we show that ASK1 translocates from the cytoplasm to the nucleus in HEK293 cells and human cardiomyocytes in response to hydrogen peroxide (H(2)O(2)) or angiotensin respectively. Immunoprecipitation and mass spectrometry experiments reveal that ASK1 physically interacts with the karyopherin α2/β1 heterodimer in response to stress and genetic knockdown experiments confirm that this association mediates H(2)O(2)-induced ASK1 nuclear translocation. In addition, we have identified a nuclear localization signal (NLS)-like motif within the primary amino acid sequence of ASK1 composed of two clusters of basic amino acids separated by an intervening 16 amino acid spacer, KR[ACANDLLVDEFLKVSS]KKKK. Mutation of the downstream lysine cluster markedly reduces the H(2)O(2)-induced ASK1-karyopherin α2/β1 interaction and inhibits ASK1 nuclear translocation. Furthermore, we demonstrate that nuclear ASK1 is active and participates in H(2)O(2)-induced ASK1-mediated cell death. Collectively, our findings have identified a functional interaction between ASK1 and the karyopherin α2/β1 heterodimer and have also revealed a novel mechanism by which nuclear trafficking regulates the apoptotic function of ASK1 in response to stress.
authors.affiliation: Department of Molecular Therapeutics and Translational Research Institute Scripps Florida Jupiter, FL 33458, USA.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Sturchler
authors.forename: Daniel
authors.initials: D
authors.lastname: Feurstein
authors.forename: Weimin
authors.initials: W
authors.lastname: Chen
authors.forename: Patricia
authors.initials: P
authors.lastname: McDonald
authors.forename: Derek
authors.initials: D
authors.lastname: Duckett
mesh_terms: D000595:Amino Acid Sequence; D000809:Angiotensins / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D002467:Cell Nucleus / Q000378:metabolism; D049109:Cell Proliferation; D002478:Cells, Cultured; D003593:Cytoplasm / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D047468:Immunoprecipitation; D007668:Kidney / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D048848:MAP Kinase Kinase Kinase 5 / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D032383:Myocytes, Cardiac / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D019913:Nuclear Localization Signals / Q000187:drug effects; D016877:Oxidants / Q000494:pharmacology; D018384:Oxidative Stress / Q000187:drug effects*; D011485:Protein Binding; D055503:Protein Multimerization; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction / Q000187:drug effects; D028901:alpha Karyopherins / Q000235:genetics / Q000378:metabolism*; D028961:beta Karyopherins / Q000235:genetics / Q000378:metabolism*
chemical_list: D000809:Angiotensins; C490630:KPNA2 protein, human; C424166:KPNB1 protein, human; D019913:Nuclear Localization Signals; D016877:Oxidants; D028901:alpha Karyopherins; D028961:beta Karyopherins; D006861:Hydrogen Peroxide; D048848:MAP Kinase Kinase Kinase 5; C482858:MAP3K5 protein, human