Gene and protein expression of Drosophila Starvin during cold stress and recovery from chill coma

In Drosophila melanogaster, the sole member of the Bcl-2-associated anthanogene (BAG)-family proteins, called Starvin (Sty), has only been recently described. BAG proteins regulate a large range of physiological processes including life/death cell balance and stress response. The role of Sty has been poorly studied in the context of abiotic stress and particularly during and after cold stress. In this study we investigated the temporal expression of Sty gene and protein in adult flies during both the cold stress (up to 9 h at 0 degrees C) and the subsequent recovery phase (up to 8 h at 25 degrees C). Because BAG proteins can regulate positively and negatively the function of Hsp70/Hsc70, we also checked whether Sty expression was related to Hsp70 and Hsc70. Sty mRNA and Sty protein both showed a similar expression pattern: no modulation during the cold period followed by a significant up-regulation during the recovery period. A coordinated response of Sty and Hsp70 mRNA was observed, but not for Hsc70. Our findings indicate that Sty expression is part of a stress-induced program in D. melanogaster. It probably acts as a co-chaperone modulating the activity of Hsp70 chaperone machinery during recovery from cold stress. Finally our results support the suggestion that Sty and human BAG3 may be functional homologs. (C) 2010 Elsevier Ltd. All rights reserved.