The dermatomyositis-specific autoantigen Mi2 is a component of a complex containing histone deacetylase and nucleosome remodeling activities.
Histone acetylation and deacetylation were found to be catalyzed by structurally distinct, multisubunit complexes that mediate, respectively, activation and repression of transcription. ATP-dependent nucleosome remodeling, mediated by different multisubunit complexes, was thought to be involved only in transcription activation. Here we report the isolation of a protein complex that contains both histone deacetylation and ATP-dependent nucleosome remodeling activities. The complex contains the histone deacetylases HDAC1/2, histone-binding proteins, the dermatomyositis-specific autoantigen Mi2beta, a polypeptide related to the metastasis-associated protein 1, and a novel polypeptide of 32 kDa. Patients with dermatomyositis have a high rate of malignancy. The finding that Mi2beta exists in a complex containing histone deacetylase and nucleosome remodeling activities suggests a role for chromatin reorganization in cancer metastasis.