Lecture 7 - Nuclear Receptors Flashcards
What are two conclusions drawn from initial experiments involving 3H-estrogen?
- Steroid hormone acts directly within target tissue
2. Steroid hormone interacts with receptor protein
Where does the hormone encounter the receptor?
Either within the cytoplasm or the nucleus
Steroid hormone receptors preferentially accumulate within the nucleus, traversing through a special structure in the nuclear envelope. This structure is called:
the nuclear pore complex
Steroid hormones have access to all tissues in the body and enter cells directly by ______.
passive diffusion
Steroid hormone receptors contain distinct ______ and _______ domains that can function independently (an in heterologous contexts).
- hormone-binding
2. DNA-binding
Steroid hormone receptors are included within a large superfamily of related proteins that share a ___________ domain.
highly conserved DNA-binding domain
Nuclear receptors are members of a large superfamily of proteins that share a common domain organization and _________.
amino acid homology
Where do receptors for many small lipid-soluble hormones, vitamins, and metabolites localize and function?
the nucleus
NRs typically cooperate with other DNA-bound transcription factors to comprise a ________.
hormone response unit
The DNA-binding domain of nuclear receptors contains: ___________ motifs.
2 zinc-finger motifs - that are so named due to the coordination of zinc by 4 cysteine residues
Specificity of transcriptional activation by nuclear receptors is often dictated by:
accessory factors bound within complex HRUs
Anti-inflammatory and immunosuppressive actions of glucocorticoids are mediated in part by interaction of:
the glucocorticoid receptor
Interaction of the glucocorticoid receptor with transcription factors leads to:
repression of transcription from their target genes
Coactivators can contain specific enzymatic activities such as ____________.
HAT - Histone Acetyltransferase
Corepressors function to recruit specific enzymatic activities such as _________.
HDACs - Histone Deacetylases
