ATF5 promotes cell survival through transcriptional activation of Hsp27 in H9c2 cells

The activating transcription factor (ATF) family comprises a group of basic region-leucine zipper (bZIP) proteins, which have roles in development, differentiation, proliferation and apoptosis. Here we described that ATF5 could promote cell survival in heat shock stress and identified that heat shock protein 27 (Hsp27) as one of its target gene related to cell survival. The ectopic expression of ATF5 could significantly increase cell tolerance to elevated temperature and the CRE motif played an important role in upregulating Hsp27 gene promoter activity by ATF5. Also, inhibition of Hsp27 expression by RNAi could increase cell death in ATF5 ectopic expressing cells, indicating that Hsp27 involved in ATF5 mediated cell survival. Taken together, our results indicated that ATF5 promoted H9c2 cell survival in heat shock stress at least through activation of Hsp27.