Lecture 6: Receptors and Cell Signaling Flashcards

1
Q

In lipophilic signaling, what is the difference between cytoplasmic and nuclear receptors?

A

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

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2
Q

How does Gs signaling work? What are some examples?

A

GTP activates cAMP and pKa
Turns of through PDE

B adrenergic (epi) and Histamine

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3
Q

How does Gi signaling work? What are some examples?

A

Inhibits cAMP and pKa is not activated

Dopamine: increases HR
Norepi: constricts smooth muscles

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4
Q

How does Gt signaling work? What are some examples?

A

GTP activates cGMP
Turns of through PDE

Light: Rhodopsin

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5
Q

How does Gq signaling work? What are some examples?

A

GTP activates phospholipase C
activates DAG/IP3 –> increase in intracellular Ca2+

Muscarinic (Acetylcholine) - bronchoconstriction and stimulation of salivary glands

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6
Q

How do cyclic nucleotides work? What are some examples?

A

Gt signaling

  • Hydrolyze cGMP and lasts longer
  • PDE is inhibited
  • smooth muscle relaxation and vasodilation

Example: viagra and caffeine (increased HR)

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7
Q

How does cholera toxin work?

A

Gs cannot be shut off

  • overproduction of cAMP
  • CTFR ions are open –> chloride leaves
  • water and salt lost too
  • diarrhea
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8
Q

How does whooping cough work?

A

Gi is inhibited

-overproduction of cAMP

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9
Q

How does nitric oxide work?

A

NO activates cGMP
-smooth muscle relaxation and vasodilation

Cannot take drugs that inhibit cGMP PDE

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10
Q

What docking proteins recognize RTK phosphorylation and promotes downstream pathways?

A

SH2 domain of Grb2

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