Nuclear matrix targeting of steroid receptors: specific signal sequences and acceptor proteins.

The nuclear matrix provides the framework for various processes that occur within the nucleus such as transcription, replication, and splicing. As the composition of the nuclear matrix varies between different cell types, the matrix may influence cell-type-specific gene expression. A number of transcription factors have been shown to be associated with the nuclear matrix, including steroid hormone receptors that were the first transcriptional regulatory proteins localized to this compartment. In this review we highlight the most recent advances in our understanding of steroid hormone receptor targeting to the matrix. A specific nuclear matrix targeting signal (NMTS) has been identified within the glucocorticoid receptor (GR) that includes portions of its DNA-binding domain and tau2 transactivation domains. Distinct nuclear matrix acceptor proteins appear to interact within the GR NMTS and impart divergent effects on the transcriptional regulatory properties of the receptor.