Differences in the chaperone-like activities of the four main small heat shock proteins of Drosophila melanogaster

摘要: The Drosophila melanogaster family of small heat shock proteins (sHsps) is composed 4 main members (Hsp22, Hsp23, Hsp26, and Hsp27) that display distinct intracellular localization specific developmental patterns expression in the absence stress. In an attempt to determine their function, we have examined whether these chaperone-like activity using various chaperone assays. Heat-induced aggregation citrate synthase was decreased from 100 17 arbitrary units presence Hsp22 Hsp27 at a 1:1 molar ratio sHsp synthase. A 5 M excess Hsp23 Hsp26 required obtain same efficiency with either or luciferase as substrate. vitro refolding assay reticulocyte lysate, more than 50% recovered when denaturation performed Hsp22, 40% Hsp27, 30% Hsp26. These differences reactivation seemed related ability sHsps bind substrate 42°C, revealed by sedimentation analysis on sucrose gradients. Therefore, share prevent heat-induced protein are able maintain refoldable state, although different efficiencies. functional reasons for distinctive cell-specific pattern could reflect existence defined substrates each within compartments.