Lecture 6: Receptors and Cell Signaling Flashcards
In lipophilic signaling, what is the difference between cytoplasmic and nuclear receptors?
Cytoplasm: Ligand binds to HSP, activating it. Hormone-receptor complex translocates to nucleus and binds to HRE (hormone response element) in promoter region
Nuclear: Binds to DNA directly and activates complex
How does Gs signaling work? What are some examples?
GTP activates cAMP and pKa
Turns of through PDE
B adrenergic (epi) and Histamine
How does Gi signaling work? What are some examples?
Inhibits cAMP and pKa is not activated
Dopamine: increases HR
Norepi: constricts smooth muscles
How does Gt signaling work? What are some examples?
GTP activates cGMP
Turns of through PDE
Light: Rhodopsin
How does Gq signaling work? What are some examples?
GTP activates phospholipase C
activates DAG/IP3 –> increase in intracellular Ca2+
Muscarinic (Acetylcholine) - bronchoconstriction and stimulation of salivary glands
How do cyclic nucleotides work? What are some examples?
Gt signaling
- Hydrolyze cGMP and lasts longer
- PDE is inhibited
- smooth muscle relaxation and vasodilation
Example: viagra and caffeine (increased HR)
How does cholera toxin work?
Gs cannot be shut off
- overproduction of cAMP
- CTFR ions are open –> chloride leaves
- water and salt lost too
- diarrhea
How does whooping cough work?
Gi is inhibited
-overproduction of cAMP
How does nitric oxide work?
NO activates cGMP
-smooth muscle relaxation and vasodilation
Cannot take drugs that inhibit cGMP PDE
What docking proteins recognize RTK phosphorylation and promotes downstream pathways?
SH2 domain of Grb2