Importin α2 associates with chromatin via a novel DNA binding domain

The nuclear transport of functional proteins is important for facilitating appropriate gene expression. The proteins of the importin α family of nuclear transport receptors operate via several pathways to perform their nuclear protein import function. Additionally, these proteins are also reported to possess other functions, including chromatin association and gene regulation. However, these non-transport functions are not yet fully understood. Here, we report novel molecular characteristics of importin α involving the binding to multiple regions of chromatin. We identified the importin α DNA binding domain-the Nucleic Acid Associating Trolley pole domain (NAAT domain) as helical structures within the N terminal IBB Domain. We propose a “stroll and locate” model to explain how importin α associates with double-strand DNA. This is the first study to show that importin α interacts with chromatin via novel DNA binding domain.