Apoptosis is a highly conserved procedure of cell death and occurs under various stimuli, including oxidative stress. A small heat shock protein, alpha B-crystallin, is found to process resistance to apoptosis in some cells and tissues. But the mechanisms under this protective role are not fully understood. In the present study, we reported the early protective role of alpha B-crystallin against hydrogen peroxide-induced apoptosis in mice myogenic C2C12 cells. alpha B-Crystallin interacted with p53, a proapoptotic protein, during cell apoptosis and such protein interaction mainly occurred in the cytoplasm of the cells, suggesting that the interaction of alpha B-crystallin with p53 might prevent the translocation of p53 from cytoplasm to mitochondria. Hence, this study provides a hint that alpha B-crystallin affects on p53 mitochondrial translocation during oxidative stress-induced apoptosis. (c) 2006 Elsevier Inc. All rights reserved.