Nuclear Receptors (Maize) Flashcards
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
