title: DNA damage-induced activation of CUL4B targets HUWE1 for proteasomal degradation.
abstract: The E3 ubiquitin ligase HUWE1/Mule/ARF-BP1 plays an important role in integrating/coordinating diverse cellular processes such as DNA damage repair and apoptosis. A previous study has shown that HUWE1 is required for the early step of DNA damage-induced apoptosis, by targeting MCL-1 for proteasomal degradation. However, HUWE1 is subsequently inactivated, promoting cell survival and the subsequent DNA damage repair process. The mechanism underlying its regulation during this process remains largely undefined. Here, we show that the Cullin4B-RING E3 ligase (CRL4B) is required for proteasomal degradation of HUWE1 in response to DNA damage. CUL4B is activated in a NEDD8-dependent manner, and ubiquitinates HUWE1 in vitro and in vivo. The depletion of CUL4B stabilizes HUWE1, which in turn accelerates the degradation of MCL-1, leading to increased induction of apoptosis. Accordingly, cells deficient in CUL4B showed increased sensitivity to DNA damage reagents. More importantly, upon CUL4B depletion, these phenotypes can be rescued through simultaneous depletion of HUWE1, consistent with the role of CUL4B in regulating HUWE1. Collectively, these results identify CRL4B as an essential E3 ligase in targeting the proteasomal degradation of HUWE1 in response to DNA damage, and provide a potential strategy for cancer therapy by targeting HUWE1 and the CUL4B E3 ligase.
authors.affiliation: Department of Cell Biology, School of Basic Medical Sciences, Peking University, Beijing 100191, China Institute of Systems Biology, Peking University, Beijing 100191, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Yi
authors.affiliation: Department of Cell Biology, School of Basic Medical Sciences, Peking University, Beijing 100191, China.
authors.forename: Guang
authors.initials: G
authors.lastname: Lu
authors.affiliation: Department of Cell Biology, School of Basic Medical Sciences, Peking University, Beijing 100191, China.
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.affiliation: Department of Breast Surgery, the First Hospital of Jilin University, Changchun 130021, China.
authors.forename: Xiaozhen
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Cell Biology, School of Basic Medical Sciences, Peking University, Beijing 100191, China.
authors.forename: Li
authors.initials: L
authors.lastname: Cao
authors.affiliation: Department of Cell Biology, School of Basic Medical Sciences, Peking University, Beijing 100191, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Lin
authors.affiliation: Department of Cell Biology, School of Basic Medical Sciences, Peking University, Beijing 100191, China.
authors.forename: Sha
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Department of Cell Biology, School of Basic Medical Sciences, Peking University, Beijing 100191, China Institute of Systems Biology, Peking University, Beijing 100191, China gzshao@bjmu.edu.cn.
authors.forename: Genze
authors.initials: G
authors.lastname: Shao
mesh_terms: D017209:Apoptosis; D002460:Cell Line; D044842:Cullin Proteins / Q000378:metabolism*; D004249:DNA Damage; D015536:Down-Regulation; D004789:Enzyme Activation; D006801:Humans; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism*; D025521:Tumor Suppressor Proteins; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism*; D054875:Ubiquitination
chemical_list: C517832:CUL4B protein, human; D044842:Cullin Proteins; D025521:Tumor Suppressor Proteins; C502830:HUWE1 protein, human; D044767:Ubiquitin-Protein Ligases; D046988:Proteasome Endopeptidase Complex