Differential intracellular localization of Hsp70 in the gill and heart tissue of fresh water prawn Macrobrachium malcolmsonii during thermal stress.

Exposure of organisms to heat stress induces the expression of evolutionarily conserved proteins called the stress proteins or heat shock proteins (HSPs). At the cellular level, HSPs by acting as molecular chaperone prevents the heat induced aggregation of denatured proteins and play a significant role in adaptation to temperature. Among different HSP family members, Hsp70 is the highly conserved and ubiquitously expressed protein. The present study is carried out to detect changes in the localization of Hsp70/Hsc70 in gill and heart tissues of control and heat shocked juveniles of Macrobrachium malcolmsonii that could be correlated with the functional significance of these two isoforms. Two groups of prawn acclimated at 30 °C were exposed to reported optimum Hsp70 induction temperatures of 36 °C and 38 °C for heart and gill, respectively, for a duration of 48 h. These tissues were processed by immunocytochemical methods to detect intra-cellular localization of Hsp70/Hsc70. Western blotting analysis was performed to determine the cytoplasmic or nuclear localization of Hsp70/Hsc70 and band intensity was detected in total lysate, cytosolic and nuclear extracts of gill and heart tissue. The present investigation clearly shows that there are alterations in the intracellular localization of Hsp70/Hsc70 in the cells of the gill and heart tissues of M. malcolmsonii following heat stress. The western blotting results corroborate the results obtained by immunohistochemical localisation. The differential intracellular localization of Hsp70/Hsc70 appears to indicate the functional roles of this stress protein during exposure to thermal stress.