title: Activation of the proteasome during Xenopus egg activation implies a link between proteasome activation and intracellular calcium release.
abstract: Ubiquitin-dependent proteolysis is required for cell cycle progression. Here, we demonstrate that the proteasome is activated during in vivo Xenopus egg activation, induced by treatment with the calcium ionophore A23187. It was found that activation is due to the calcium-induced assembly of the 26 S proteasome from the 20 S proteasome. We propose that proteasome activation is regulated by cell cycle calcium transients, which are controlled upstream by an endogenous cell cycle oscillator that is independent of the cyclin-dependent kinase cycle.
authors.affiliation: Department of Biochemistry, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Aizawa
authors.forename: H
authors.initials: H
authors.lastname: Kawahara
authors.forename: K
authors.initials: K
authors.lastname: Tanaka
authors.forename: H
authors.initials: H
authors.lastname: Yokosawa
mesh_terms: D000818:Animals; D015153:Blotting, Western; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002453:Cell Cycle; D002614:Chelating Agents / Q000494:pharmacology; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D004789:Enzyme Activation; D007700:Kinetics; D009097:Multienzyme Complexes / Q000378:metabolism*; D009865:Oocytes / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D006656:Protamine Kinase / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex; D013997:Time Factors; D014452:Ubiquitins / Q000378:metabolism; D014982:Xenopus laevis
chemical_list: D002614:Chelating Agents; D009097:Multienzyme Complexes; D014452:Ubiquitins; C070379:1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid acetoxymethyl ester; D000001:Calcimycin; D004533:Egtazic Acid; D006656:Protamine Kinase; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex; D002118:Calcium