αB-crystallin, a small heat shock protein, modulates NF-κB activity in a phosphorylation-dependent manner and protects muscle myoblasts from TNF-α induced cytotoxicity

► αB-crystallin and TNF-α are upregulated during myoblast differentiation. ► αB-crystallin associates with and enhances IKKβ activity, facilitating I-kBα degradation.► Ser-59 phosphorylation of αB-crystallin is necessary to activate NF-κB pathway. ► Upregulation of αB-crystallin leads to elevation of antiapoptotic protein Bcl 2. ► αB-crystallin protects C2C12 cells from TNF-α induced cytotoxicity.