title: Tumor necrosis factor alpha-induced desumoylation and cytoplasmic translocation of homeodomain-interacting protein kinase 1 are critical for apoptosis signal-regulating kinase 1-JNK/p38 activation.
abstract: The apoptosis signal-regulating kinase 1 (ASK1)-JNK/p38 signaling pathway is pivotal component in cell apoptosis and can be activated by a variety of death stimuli including tumor necrosis factor (TNF) alpha and oxidative stress (reactive oxygen species). However, the mechanism for ASK1 activation is not fully understood. We have recently identified ASK1-interacting protein (AIP1) as novel signal transducer in TNFalpha-induced ASK1 activation by facilitating dissociation of ASK1 from its inhibitor 14-3-3. In the present study, we employed yeast two-hybrid system using the N-terminal domain of AIP1 as bait and identified homeodomain-interacting protein kinase 1 (HIPK1) as an AIP1-associated protein. Interestingly, we showed that TNFalpha induced HIPK1 desumoylation concomitant with a translocation from nucleus to cytoplasm at 15 min followed by a return to nucleus by 60 min. The kinetics of HIPK1 translocation correlates with those of stress-induced ASK1-JNK/P38 activation. A specific JNK inhibitor blocked the reverse but not the initial translocation of HIPK1, suggesting that the initial translocation is an upstream event of ASK1-JNK/p38 signaling and JNK activation regulates the reverse translocation as a feedback mechanism. Consistently, expression of HIPK1 increased, whereas expression of a kinase-inactive form (HIPK1-D315N) or small interference RNA of HIPK1 decreased stress-induced ASK1-JNK/P38 activation without effects on IKK-NF-kappaB signaling. Moreover, a sumoylation-defective mutant of HIPK1 (KR5) localizes to the cytoplasm and is constitutively active in ASK1-JNK/P38 activation. Furthermore, HIPK1-KR5 induces dissociation of ASK1 from its inhibitors 14-3-3 and thioredoxin and synergizes with AIP1 to induce ASK1 activation. Our study suggests that TNFalpha-induced desumoylation and cytoplasmic translocation of HIPK1 are critical in TNFalpha-induced ASK1-JNK/p38 activation.
authors.affiliation: Interdepartmental Program in Vascular Biology and Transplantation, Boyer Center for Molecular Medicine, Department of Pathology, Yale University School of Medicine, New Haven, Connecticut 06510, USA.
authors.forename: Xianghong
authors.initials: X
authors.lastname: Li
authors.forename: Rong
authors.initials: R
authors.lastname: Zhang
authors.forename: Dianhong
authors.initials: D
authors.lastname: Luo
authors.forename: Sang-Joon
authors.initials: SJ
authors.lastname: Park
authors.forename: Qian
authors.initials: Q
authors.lastname: Wang
authors.forename: Yongsok
authors.initials: Y
authors.lastname: Kim
authors.forename: Wang
authors.initials: W
authors.lastname: Min
mesh_terms: D048948:14-3-3 Proteins / Q000378:metabolism; D021581:Active Transport, Cell Nucleus; D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism; D002417:Cattle; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D003593:Cytoplasm / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000166:cytology; D004789:Enzyme Activation; D019084:Fluorescent Antibody Technique, Indirect; D017930:Genes, Reporter; D006801:Humans; D015151:Immunoblotting; D047468:Immunoprecipitation; D007700:Kinetics; D048848:MAP Kinase Kinase Kinase 5 / Q000378:metabolism*; D020930:MAP Kinase Kinase Kinases / Q000378:metabolism; D018613:Microscopy, Confocal; D008954:Models, Biological; D009154:Mutation; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D011494:Protein Kinases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D015398:Signal Transduction; D013879:Thioredoxins / Q000737:chemistry; D013997:Time Factors; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000737:chemistry* / Q000378:metabolism; D020798:Two-Hybrid System Techniques; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*
chemical_list: D048948:14-3-3 Proteins; D002352:Carrier Proteins; D034741:RNA, Small Interfering; D014409:Tumor Necrosis Factor-alpha; D013879:Thioredoxins; D011494:Protein Kinases; C115113:Hipk1 protein, mouse; D017346:Protein Serine-Threonine Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D048848:MAP Kinase Kinase Kinase 5; D020930:MAP Kinase Kinase Kinases