Cytoplasmic-nuclear translocation of the Hsp70 protein during environmental stress in Trypanosoma cruzi.

The present study provides immunological evidence of the constitutive presence of the Hsp70 protein in the cytoplasm of logarithmically growing T. cruzi parasites cultured at the normal temperature of 28 degrees C and of the translocation of the protein to the nucleus upon a heat shock treatment (2 hours at 37 degrees C). The nuclear translocation of the protein must depend on other factors beside the temperature per se since at 28 degrees C, in stationary phase growing parasites, the Hsp70 protein was present in both the cytoplasm and the nucleus. During recovery at 28 degrees C the protein leaves the nuclei but the nuclear-cytoplasmic translocation of the protein is a much more gradual process than its initial transport to the nucleus. Since the isoform of the nuclear Hsp70 is different from that found in the cytoplasm it is likely that before translocation to the nucleus the cytoplasmic Hsp70 nuclear precursor must undergo a specific modification.