title: CUL4-DDB1-CDT2 E3 Ligase Regulates the Molecular Clock Activity by Promoting Ubiquitination-Dependent Degradation of the Mammalian CRY1.
abstract: The CUL4-DDB1 E3 ligase complex serves as a critical regulator in various cellular processes, including cell proliferation, DNA damage repair, and cell cycle progression. However, whether this E3 ligase complex regulates clock protein turnover and the molecular clock activity in mammalian cells is unknown. Here we show that CUL4-DDB1-CDT2 E3 ligase ubiquitinates CRY1 and promotes its degradation both in vitro and in vivo. Depletion of the major components of this E3 ligase complex, including Ddb1, Cdt2, and Cdt2-cofactor Pcna, leads to CRY1 stabilization in cultured cells or in the mouse liver. CUL4A-DDB1-CDT2 E3 ligase targets lysine 585 within the C-terminal region of CRY1 protein, shown by the CRY1 585KA mutant's resistance to ubiquitination and degradation mediated by the CUL4A-DDB1 complex. Surprisingly, both depletion of Ddb1 and over-expression of Cry1-585KA mutant enhance the oscillatory amplitude of the Bmal1 promoter activity without altering its period length, suggesting that CUL4A-DDB1-CDT2 E3 targets CRY1 for degradation and reduces the circadian amplitude. All together, we uncovered a novel biological role for CUL4A-DDB1-CDT2 E3 ligase that regulates molecular circadian behaviors via promoting ubiquitination-dependent degradation of CRY1.
authors.affiliation: Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America.
authors.forename: Xin
authors.initials: X
authors.lastname: Tong
authors.affiliation: Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America.
authors.forename: Deqiang
authors.initials: D
authors.lastname: Zhang
authors.affiliation: Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America.
authors.forename: Anirvan
authors.initials: A
authors.lastname: Guha
authors.affiliation: Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America.
authors.forename: Blake
authors.initials: B
authors.lastname: Arthurs
authors.affiliation: Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America.
authors.forename: Victor
authors.initials: V
authors.lastname: Cazares
authors.affiliation: Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America.
authors.forename: Neil
authors.initials: N
authors.lastname: Gupta
authors.affiliation: Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America.
authors.forename: Lei
authors.initials: L
authors.lastname: Yin
mesh_terms: D000818:Animals; D001683:Biological Clocks; D056931:Cryptochromes / Q000378:metabolism*; D008297:Male; D051379:Mice; D059748:Proteolysis; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism*; D054875:Ubiquitination
chemical_list: C538964:Cry1 protein, mouse; D056931:Cryptochromes; D044767:Ubiquitin-Protein Ligases