Structure/ function analyses of sarco(endo)plasmic reticulum CA2+ - ATPases : effects of oxidative stress , redox signaling and protein-protein interactions

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Muscle cells in our body are often exposed to a variety of stressful conditions such as heat stress or intense exercise or in association with a variety of diseases. When muscle cells are exposed to stress the calcium level inside the cells increases and it is believed that cell damage and even cell death will occur as a result of the increased cellular calcium. One major reason for the increase in calcium with stress is that the enzyme responsible for maintaining normal calcium levels in muscle, namely the Ca2+ pump, becomes damaged with stress. Therefore, it would be expected that cell damage would be reduced and survival would be increased after stress if the calcium pump could somehow be protected. We have recently shown that a protein called heat shock protein 70 (Hsp70) can protect the calcium pump in muscle during heat stress but we haven't figured out exactly how this works yet or whether other proteins in muscle might also protect the calcium pump. The goal of this project is to examine specifically how Hsp70 and two other proteins called phospholamban and sarcolipin, protect the Ca2+ pump under a wide range of stress conditions. We will manipulate the levels of the Ca2+ pump, Hsp70, phospholamban and sarcolipin in living cells using recombinant DNA technology and then expose the cells to various types of stress (i.e. heat, reactive oxygen species, etc.) followed by assessment of structural and functional damage to the Ca2+ pump. Another goal of our research is to understand what controls the amount of Hsp70 that is normally found in muscle under resting and exercise conditions. We will recruit young (<30 years) and old (>70 years) men and women for our experiments to investigate potential sex and age differences in the Hsp70 response to exercise in human skeletal muscle. This work could have important implications that extend into a number of fields (i.e. cancer and heart disease research) because protecting the Ca2+ pump could prevent increases in calcium and improve cell survival following stress.