title: KLHL39 suppresses colon cancer metastasis by blocking KLHL20-mediated PML and DAPK ubiquitination.
abstract: Cullin 3 (Cul3)-family ubiquitin ligases use the BTB-domain-containing proteins for the recruitment of substrates, but the regulation of this family of ubiquitin ligases has not been completely understood. KLHL20 is a BTB-family protein and targets tumor suppressor promyelocytic leukemia protein (PML) and death-associated protein kinase (DAPK) to its kelch-repeat domain for ubiquitination and degradation. Here, we show that another BTB-kelch protein KLHL39 is recruited to the substrate-binding domain of KLHL20 but is not a substrate of Cul3-KLHL20 complex. Interestingly, KLHL39 does not bind Cul3 because of the absence of certain conserved residues in the BTB domain. Instead, KLHL39 blocks KLHL20-mediated ubiquitination of PML and DAPK by disrupting the binding of these substrates to KLHL20 as well as the binding of KLHL20 to Cul3. Through the two mechanisms, KLHL39 increases the stability of PML and DAPK. In human colon cancers, downregulations of KLHL39, PML and DAPK are associated with metastatic progression. Furthermore, preclinical data indicate that KLHL39 promotes colon cancer migration, invasion and survival in vitro and metastasis in vivo through a PML- and DAPK-dependent mechanism. Our study identifies KLHL39 as a negative regulator of Cul3-KLHL20 ubiquitin ligase and reveals a role of KLHL39-mediated PML and DAPK stabilization in colon cancer metastasis.
authors.affiliation: Graduate Institute of Cancer Biology and Drug Discovery, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan.|Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan.
authors.forename: H Y
authors.initials: HY
authors.lastname: Chen
authors.affiliation: Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan.|Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: J Y
authors.initials: JY
authors.lastname: Hu
authors.affiliation: Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan.|Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: T H
authors.initials: TH
authors.lastname: Chen
authors.affiliation: Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan.
authors.forename: Y C
authors.initials: YC
authors.lastname: Lin
authors.affiliation: Graduate Institute of Cancer Biology and Drug Discovery, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan.
authors.forename: X
authors.initials: X
authors.lastname: Liu
authors.affiliation: Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan.
authors.forename: M Y
authors.initials: MY
authors.lastname: Lin
authors.affiliation: Institute of Biomedical Science, Academia Sinica, Taipei, Taiwan.
authors.forename: Y D
authors.initials: YD
authors.lastname: Lang
authors.affiliation: Graduate Institute of Cancer Biology and Drug Discovery, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan.
authors.forename: Y
authors.initials: Y
authors.lastname: Yen
authors.affiliation: Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan.|Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan.|Institute of Biochemical Sciences, College of Life Science, National Taiwan University, Taipei, Taiwan.
authors.forename: R H
authors.initials: RH
authors.lastname: Chen
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism*; D045744:Cell Line, Tumor; D003110:Colonic Neoplasms / Q000378:metabolism / Q000473:pathology*; D064550:Death-Associated Protein Kinases / Q000378:metabolism*; D005260:Female; D064593:Heterografts; D006801:Humans; D007150:Immunohistochemistry; D047468:Immunoprecipitation; D051379:Mice; D008819:Mice, Nude; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis; D009687:Nuclear Proteins / Q000378:metabolism*; D000071156:Promyelocytic Leukemia Protein; D034622:RNA Interference; D016601:RNA-Binding Proteins; D046888:Tissue Array Analysis; D014157:Transcription Factors / Q000378:metabolism*; D014162:Transfection; D025521:Tumor Suppressor Proteins / Q000378:metabolism*; D054875:Ubiquitination
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; C114207:IVNS1ABP protein, human; C550011:KLHL20 protein, human; D009687:Nuclear Proteins; D000071156:Promyelocytic Leukemia Protein; D016601:RNA-Binding Proteins; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; C070576:PML protein, human; C579096:DAPK1 protein, human; D064550:Death-Associated Protein Kinases