Deng, GonghuaLi, JunliLiu, MeidongLiu, ShuangTu, ZizhiXiao, Xianzhong2008-06-172008-06-172005-06-201611-2156http://hdl.handle.net/2003/2564710.17877/DE290R-8177aB-crystallin, a major small heat shock protein, has recently been shown to exert inhibitory effects on apoptosis, while the responsible mechanisms remain largely unknown. In the present study, we discovered that aB-crystallin protected mouse myoblast C2C12 cells against oxidative stress-induced apoptosis. During hydrogen peroxide-induced apoptosis, aBcrystallin showed that it decreased the redistribution level of phosphatidylserine (PS), reduced the release of cytochrome C and Smac/Diablo from mitochondria into cytoplasm, and decreased the cleavage of Bid. Interestingly, immunoprecipitation experiments with anti-aBcrystallin and anti-myc-tag antibodies demonstrated respectively an interaction between aBcrystallin and p53 during hydrogen peroxide induced apoptosis. Both the NH2-terminal and COOH-terminal regions of aB-crystallin could interact with p53, suggesting two domains of aB-crystallin are necessary for the interaction. Electrophoresis mobility shift assay (EMSA) and luciferase assay further demonstrated that aB-crystallin inhibited the upregulation of the DNA-binding, as well as the transactivation activity of p53 induced by hydrogen peroxide. Our results show that aB-crystallin has a protective role in oxidative stress induced apoptosis by interference with the mitochondrial death pathway.enEXCLI Journal ; Vol. 4, 2005aB-crystallinapoptosisBidCytochrome Chydrogen peroxidemitochondriap53Smac/Diablo610article (journal)