EFFECT OF EGF ON THE INTRACELLULAR DISTRIBUTION OF HSP70 AND HDJ1 IN A431 CELLS
A. L. Evdonin,1 N. V. Tsupkina, B. A. Margulis, N. D. Medvedeva
Institute of Cytology RAS, St. Petersburg, Russia;
1 e-mail: evdonin@tnail.ru
The intracellular distribution of hsp70 and hdjl was studied using immunofluorescent method. In nonstimulated cells hsp70 and hdjl were observed in the
cytoplasm of A431 cells. When 100 ng/ml EGF was added for 15 min, both hsp70 and hdjl were accumulated in the nuclei. Later on (up to Ih) hsp70 was exported from the nuclei
to be observed mainly in the cytoplasm, whereas hdjl remained in the nuclei. In cells exposed to tyrphostin AG1478, this inhibitor of tyrosine kinase activity of EGF receptor
prevented EGF-dependent accumulation of hsp70 and hdjl in the nuclei. U73122, an inhibitor of phospholipase Ñ activity, induced tyrosine phosphorylation of EGF receptor
without EGF stimulation. In cells treated with U73122, both hsp70 and hdjl were detected in the nuclei of non-stimulated cells. It is concluded that the intracellular distribution of
heat shock proteins in A431 cells depends on tyrosine kinase activity of EGF receptor. Here we report for the first time the influence of EGF on the intracellular redistribution of
heat shock proteins.
Key words: heat shock proteins, epidermal growth factor, tyrphostin AG1478, A431 cells
