2008 Volume 108 Issue 2 Pages 222-226
To explore the cellular effects of mild electrical stimulation (MES), we treated A549 cells with low-intensity direct current at 5 V applied for 10 min. MES did not induce cell cytotoxicity or the unfolded protein response (UPR). Interestingly, the expression of ubiquitinated proteins and heat shock protein (Hsp) 72 was increased but not that of other Hsps. MES attenuated the degradation of Hsp72, which is a substrate of the proteasome-ubiquitin system. These results, along with the observed increase in expression of ubiquitinated proteins, imply that MES may affect the proteasome system, which regulates the fate of many proteins.