title: Changes in composition and activities of 26S proteasomes under the action of doxorubicin--apoptosis inductor of erythroleukemic K562 cells.
abstract: Changes in the subunit composition, phosphorylation of the subunits, and regulation of the activities of 26S proteasomes in proliferating cells undergoing programmed cell death have not been studied so far. Moreover, there are no reports on phosphorylation of proteasome subunits both in normal and in neoplastic cells during apoptosis. The data of the present study show for the first time that apoptosis inductor doxorubicin regulates subunit composition, enzymatic activities, and phosphorylation state of 26S proteasomes in neoplastic (proerythroleukemic K562) cells or, in other words, induces reprogramming of proteasome population. Furthermore, the phosphorylation state of proteasomes is found to be the mechanism controlling specificity of proteasomal proteolytic and endoribonuclease activities.
authors.affiliation: Laboratory of Regulation of Gene Expression, Institute of Cytology, Russian Academy of Sciences, Tikhoretsky Ave, 4, St. Petersburg 194064, Russia. atsimokha@mail.cytspb.rssi.ru
authors.forename: Anna S
authors.initials: AS
authors.lastname: Tsimokha
authors.forename: Alexey G
authors.initials: AG
authors.lastname: Mittenberg
authors.forename: Valentina A
authors.initials: VA
authors.lastname: Kulichkova
authors.forename: Irina V
authors.initials: IV
authors.lastname: Kozhukharova
authors.forename: Larisa N
authors.initials: LN
authors.lastname: Gause
authors.forename: Irina M
authors.initials: IM
authors.lastname: Konstantinova
mesh_terms: D000903:Antibiotics, Antineoplastic / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D004317:Doxorubicin / Q000494:pharmacology*; D015180:Electrophoresis, Gel, Two-Dimensional; D006801:Humans; D020014:K562 Cells / Q000378:metabolism / Q000473:pathology; D010766:Phosphorylation; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism*
chemical_list: D000903:Antibiotics, Antineoplastic; D004317:Doxorubicin; D046988:Proteasome Endopeptidase Complex; C061553:ATP dependent 26S protease