Nuclear transport of steroid hormone receptors.

Nuclear receptors (NRs) comprise a superfamily of ligand-regulated transcription factors implicated in a host of physiological processes, including development, differentiation, and proliferation. Translated in the cytoplasm, NRs must undergo import into the nucleus in order to modulate transcription of target genes in response to cognate hormones. NRs also undergo export from the nucleus, and there is emerging evidence that NR nucleocytoplasmic shuttling contributes to their regulation. Nucleocytoplasmic shuttling may provide a nexus for crosstalk between NRs and kinase pathways. Here we review some of the key studies on nuclear import and export of steroid hormone receptors within the NR superfamily, address some of the challenges in experimental dissection of NR transport and discuss recent findings linking specific kinase pathways to NR export.