ER stress response during the differentiation of H9 cells induced by retinoic acid

► RA upregulated GRP78/Bip, Gp78 and Hrd1 during a 5-day H9 cell differentiation. ► eIF2α and phosphorylated eIF2α were downregulated in H9 cells but not in 293 cells treated with RA. ► XBP-1 exhibited a sharp downregulation in the above H9 cells. ► Protein Bcl2 was undetectable in the H9 cells and H9 derived cells but was expressed in the 293 cells. ► GRP78/Bip, XBP-1 and Bcl2, were all upregulated in H9 cells treated with RA for 29 days.