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Cancer Cell death Cell cycle Cytoskeleton Exo/endocytosis Differentiation Division Organelles Signalling Stem cells Trafficking
Cell Biology International (2007) 31, 338–348 (Printed in Great Britain)
Changes in composition and activities of 26S proteasomes under the action of doxorubicin – apoptosis inductor of erythroleukemic K562 cells
Anna S. Tsimokhaa*, Alexey G. Mittenberga, Valentina A. Kulichkovaa, Irina V. Kozhukharovaa, Larisa N. Gauseb and Irina M. Konstantinovaa
aLaboratory of Regulation of Gene Expression, Institute of Cytology, Russian Academy of Sciences, Tikhoretsky Ave, 4, St. Petersburg 194064, Russia
bKoltsov Institute of Developmental Biology, Russian Academy of Sciences, 26, Vavilov st., Moscow 119334, Russia


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.

Key words: 26S proteasomes, Apoptosis, Doxorubicin, Endoribonuclease and proteolytic activities, Phosphorylation.

*Corresponding author. Tel.: +7 812 297 3740; fax: +7 812 297 0341.


ISSN Print: 1065-6995
ISSN Electronic: 1095-8355
Published by Portland Press Limited on behalf of the International Federation for Cell Biology (IFCB)