Defined sequence segments of the small heat shock proteins HSP25 and alphaB-crystallin inhibit actin polymerization.

The interaction of small heat shock proteins (sHSPs) with the actin cytoskeleton has been described and some members of this family, e.g. chicken and murine HSP25 (HSP27), inhibit the polymerization of actin in vitro.

Induction of the small stress protein, hsp25, in Ehrlich ascites carcinoma cells by anticancer drugs.

Treatment of in vitro cultured Ehrlich ascites carcinoma cells with cisplatin, daunomycin, doxorubicin, cytosine arabinoside, 3'-fluorodeoxythymidine, colchicine and vincristine in cytostatically effective concentrations results in significantly increased levels of the small stress protein, hsp25, as analyzed by immunoblotting. However, no induction of hsp25 could be detected after treatment of the tumour cells with 5-fluorouracil, aminopterin, amethopterin, mithramycin and cyclophosphamide. None of these cytostatic drugs induces hsp70.

Translational regulation of the mammalian growth-related protein P23: involvement of eIF-4E.

Synthesis of the mammalian growth-related protein P23 is rapidly induced after serum stimulation of mouse fibroblasts and Ehrlich ascites tumour cells. This induction occurs at the translational level. Growth-induction leads also to an increase in phosphorylation of the rate-limiting initiation factor eIF-4E.

Over-expression of the small heat-shock protein, hsp25, inhibits growth of Ehrlich ascites tumor cells.

hsp25 is a small, growth-related, mammalian stress protein which is highly accumulated in the stationary phase of Ehrlich ascites tumor in vivo. Ehrlich ascites cells cultivated in vitro under conditions of continuous exponential growth express hsp25 only at a low level. These cells were stably transfected with an eukaryotic expression vector carrying the coding sequence of the small heat-shock protein, hsp25, under control of the murine metallothionein promoter.