Nuclear Receptors

Question 1

Are nuclear receptors transcription factors?

Answer 1

Yes

Question 2

What does binding of a ligand to a NR do?

Answer 2

Induce conformational change and alter its ability to induce gene transcription

Question 3

Give examples it NR ligands?

Answer 3

Vitamins,hormones, metabolites and xenobiotics

Question 4

What are the 2 NR domain structures?

Answer 4

DNA binding domain DBD

Ligand binding domain LBD

Question 5

What motifs do co repressors and co activators have?

Answer 5

Co repressors- LXXXI/ LXXXL

Co activators- LXXLL

Question 6

How do co repressors block recruitment of polymerase?

Answer 6

contain histone deacetylases
Remove acetyl groups from his tones
Generate compact chromatin structure
Block recruitment of polymerase

Question 7

How do antagonist ligands work in cancer treatment?

Answer 7

Block estrogen dependent growth so mimic estradiol by binding reversibly to the ER LBD
Bulky nature pushes activation helix out of position
Co activators unable to form complex with ER

Question 8

What do nuclear receptors act as?

Answer 8

Sensors for intracellular levels of small molecules or metabolites