Post-Translational Modification and Regulation of the Chaperone Hsp27 during Apoptosis

Apoptosis is an essential cellular mechanism by which cells undergo changes resulting in cell death. The failure of a cell to undergo apoptosis is central to cancer progression and chronic inflammatory diseases. In contrast, uncontrolled apoptosis may lead to neurodegenerative diseases such as Alzheimer's and Parkinson's. Therefore, studying the apoptotic pathway can lead to a greater understanding and development of therapeutic approaches. Recently, we identified a plant compound, apigenin, which induces apoptosis and has anti-cancer and anti-inflammatory properties. An essential protein in the apoptotic pathway is caspase-3. Caspase-3 is responsible for advancing the apoptotic pathway, resulting in cell death. A key inhibitor of capase-3 is the small heat shock protein 27 (Hsp27). Hsp27 acts as a cell survival factor by interacting with caspase-3. This interaction inhibits caspase-3's ability to progress apoptosis. Hsp27 can be regulated by the addition of phosphate molecules to its structure (phosphorylation). The phosphorylation status of Hsp27 is known to affect its ability to bind to other proteins and perhaps, its ability to bind to caspase-3. It is proposed that Hsp27 phosphorylation releases Hsp27 from caspase-3, thus allowing the cell to die by apoptosis. Here, we propose to study the phosphorylation of Hsp27 during apigenin-induced-apoptosis. Our work will help us to gain a greater knowledge of the regulation of apoptosis through caspase-3 and Hsp27.No embarg