title: APC/C(Cdh1) targets brain-specific kinase 2 (BRSK2) for degradation via the ubiquitin-proteasome pathway.
abstract: Studies of brain-specific kinase 2 (BRSK2), an AMP-activated protein kinase (AMPK)-related kinase, and its homologs suggest that they are multifunctional regulators of cell-cycle progression. BRSK2, which contains a ubiquitin-associated (UBA) domain, is polyubiquitinated in cells. However, the regulatory mechanisms and exact biological function of BRSK2 remain unclear. Herein, we show that BRSK2 co-localizes with the centrosomes during mitosis. We also demonstrate that BRSK2 protein levels fluctuate during the cell cycle, peaking during mitosis and declining in G1 phase. Furthermore, Cdh1, rather than Cdc20, promotes the degradation of BRSK2 in vivo. Consistent with this finding, knock-down of endogenous Cdh1 blocks BRSK2 degradation during the G1 phase. The conserved KEN box of BRSK2 is required for anaphase-promoting complex/cyclosome-Cdh1 (APC/C(Cdh1))-dependent degradation. Additionally, overexpression of either BRSK2(WT) or BRSK2(ΔKEN) increases the percentage of cells in G2/M. Thus, our results provide the first evidence that BRSK2 regulates cell-cycle progression controlled by APC/C(Cdh1) through the ubiquitin-proteasome pathway.
authors.affiliation: State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, People's Republic of China.
authors.forename: Ruwei
authors.initials: R
authors.lastname: Li
authors.forename: Bo
authors.initials: B
authors.lastname: Wan
authors.forename: Jun
authors.initials: J
authors.lastname: Zhou
authors.forename: Yingli
authors.initials: Y
authors.lastname: Wang
authors.forename: Ting
authors.initials: T
authors.lastname: Luo
authors.forename: Xiuting
authors.initials: X
authors.lastname: Gu
authors.forename: Fang
authors.initials: F
authors.lastname: Chen
authors.forename: Long
authors.initials: L
authors.lastname: Yu
mesh_terms: D000595:Amino Acid Sequence; D064173:Anaphase-Promoting Complex-Cyclosome; D000818:Animals; D064200:Cdh1 Proteins; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000378:metabolism*; D045744:Cell Line, Tumor; D018385:Centrosome / Q000378:metabolism; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D008938:Mitosis; D008969:Molecular Sequence Data; D009154:Mutation; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D025801:Ubiquitin / Q000378:metabolism*; D043743:Ubiquitin-Protein Ligase Complexes / Q000378:metabolism*; D054875:Ubiquitination; D015854:Up-Regulation
chemical_list: D064200:Cdh1 Proteins; D018797:Cell Cycle Proteins; C577584:FZR1 protein, human; D025801:Ubiquitin; D043743:Ubiquitin-Protein Ligase Complexes; D064173:Anaphase-Promoting Complex-Cyclosome; C507732:Brsk2 protein, human; D017346:Protein Serine-Threonine Kinases; D046988:Proteasome Endopeptidase Complex