DECREASE OF HEAT-SHOCK PROTEIN-27 28 WITH HEAT-STRESS IN HTLV-I-TRANSFORMED CELLS/

We have previously reported an increase of human T-lymphotropic leukem ia/lymphoma virus type I (HTLV-I) replication after heat treatment of MT-2 cells, an HTLV-I-transformed human lymphoid cell line. In this st udy, we investigated the effect of beat stress on the expression of Hs p27/28 in MT-2 cells. In contrast with previous studies of other cell types, a decrease of Hsp27/28 expression in MT-2 cells and an increase of Hsp70 family proteins in both MT-2 and uninfected lymphoid CEM cel ls were found following heat treatment at 42 degrees C. Furthermore, h eat treatment resulted in an early rapid increase in the phosphorylate d form of Hsp27/28 in both MT-2 and CEM cells. The results suggest tha t early post-translational phosphorylation of HSP27/28 could be a dete rminant of the ability of MT-2 cells to survive hyperthermia. (C) 1994 Academic Press, Inc.