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Flashcards in Nuclear Receptors (Maize) Deck (14):

Types of Receptors

- Membrane
- Ion channel
- Nuclear or cytoplasmic


General Mechanism of Action of Nuclear Receptors

Nuclear receptors modulate protein synthesis either directly of indirectly by inhibiting or promoting DNA transcription of proteins.


Receptor Structure

C-terminal: where the drug binds
N-terminal: the part of the receptor that binds to the promoter region
Zinc fingers/sticky fingers: what binds to the DNA or transcription factor, also covered with heat shock proteins


Direct Mechanism of Action

Drug-receptor complex binds to the DNA response element to inhibit or promote transcription, requires two drug receptor complexes that bind to a response element


Indirect Mechanism of Action

Drug-receptor complex binds to a transcription factor preventing it from bind to DNA. This inhibits the transcription of inflammatory proteins and only requires one drug-receptor complex


What are the Glucocorticoid Receptors

GR-1: binds to mineralcorticoids (kidney, colon, saliva glands & hippocampus)
GR-2: bind glucocorticoids (all cells)


What are the Retinoid Receptors

Retinoic acid receptor (RAR): has alpha, beta, and gamma subtypes (gamma most abundant on the skin)
Retinoid X receptor (RXR): does not have subtypes and most are teratogenic


What is the Vitamin D Receptor

Vitamin D (VDR)


What type of dimer does glucocorticoids form

Homo-dimers only!


What type of dimer does retinoid receptors form

Hetero or Homo dimers


What type od dimer does vitamin D receptors form

Hetero-dimer with Retinoid receptors only!


What are the types of Response elements

GRE: Glucocorticoid response element
RARE: Retinoic acid response element
TRE: Transcription response element


What are the Transcription factors

Nuclear Factor Kappa B: NF-kb
Activator Protein 1: AP1


Does direct or indriect happen first

They are both happening at the same time because the drug does not know which one to specifically do first