Nuclear receptor-cofactor complexes

However, some receptors are constitutively expressed in the nucleus and this type of receptor would not be amenable to a nuclear translocation assay. The activities of nuclear receptors may be dependent upon complex interactions with a number of coregulatory proteins, commonly known as coactivators or corepressors, and modifications by post-translational means. Cell type-specific expression levels of receptors and coregulators may contribute to some, but not all, of the molecular bases for gene and functional selectivity of receptor activity. Therefore selecting a cell line that expresses both the target receptor and the necessary cofactors may be required to design an appropriate assay. 

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