Regulation of myocardial heat shock protein 70 gene expression following exercise

Post-exercise induction of myocardial heat shock protein (Hsp70) gene expression involves the activation of the heat shock transcription factor (HSF1). While the exact mechanisms governing the regulation of HSF1 are unclear, activation is believed to occur subsequent to hyperphosphorylation of specific serine residues. As two important serine kinases, protein kinase A (PKA) and protein kinase C (PKC), have been implicated in many phosphorylative events in myocardial cells, we examined the role of these kinases in the activation of Hsp70 gene expression following exercise. In this report, we show that prior administration of a PKA inhibitor, N-[2-( p-bromocinnamylamino)ethyl]-5-isoquinolinesulfonamide 2HCl (H-89; 0.36 mg/kg), significantly suppressed the elevation in Hsp70 mRNA ( P