EFFECT OF EGF ON THE ACTIVITY OF NUCLEAR AND CYTOPLASMIC 26S PROTEASOMES IN A431 CELLS
V. A. Kulichkova,1 Yu. B. Ermolaeva,1 A. G. Mittenberg,1
I. V. Volkova,1 A. S. Tsimokha,1 I. N. Evteeva,1 L. N. Cause,2
I. M. Konstantinova 1, *
1 Institute of Cytology RAS, St. Petersburg, and
2 N. K. Koltsov Institute of Developmental Biology RAS, Moscow, Russia;
* e-mail: ikonst@mail.cytspb.rssi.ru
It has been first shown that EOF regulates a proteolytic activity of proteasomes. Following a 15 min action with
100 ng/ml EGF, three types of peptidase activity of both cytoplasmic and nuclear proteasomes were induced in A431 cells, although,
this effect on different populations of proteasomes was selective. EGF preferentially stimulates chymotrypsin-like activity of
cytoplasmic proteasomes, and induces a similar increase of chymo-trypsin-like, trypsin-like and peptydylglutamyl peptide hydrolase
activities of nuclear particles. Tyrphostin, an inhibitor of tyrosine kinase activity of EOF receptor, prevents the EGF effect on
both proteolytic and RNase activity of nuclear and cytoplasmic proteasomes. It is concluded that EGF may rapidly and selectively
stimulate enzymatic activity of EGF receptor.
Key words: proteasomes, epidermal growth factor, peptidase activity, ribonucleases, tyrphostin
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