Constitutive heat shock protein 70 interacts with α-enolase and protects cardiomyocytes against oxidative stress

Constitutive heat shock protein 70 (Hsc70) is a molecular chaperone that has been shown to protect cardiomyocytes against oxidative stress. However, the molecular mechanism responsible for this protection remains uncertain. To understand the mechanism associated with the myocardial protective role of Hsc70, we have embarked upon a systematic search for Hsc70-interacting proteins. Using adenosine diphosphate (ADP) affinity chromatography and mass spectrometry, we have identified alpha-enolase, a rate-limiting enzyme in glycolysis, as a novel Hsc70-interacting protein in the myocardium of both sham and myocardial ischemia-reperfused Sprague-Dawley rat hearts. This interaction was confirmed by co-immunoprecipitation (IP) assays in the myocardial tissues and H9c2 cardiomyocytes and protein overlay assay (POA). It was further shown that Hsc70-overexpression alleviated the H(2)O(2)-induced decrease of alpha-enolase activity and cell damage, and Hsc70 deficiency aggravated the decrease of alpha-enolase activity and cell damage in H(2)O(2) treated H9c2 cells. Our research suggests that the protective effect of Hsc70 on the cardiomyocytes against oxidative stress is partly associated with its interaction with alpha-enolase.