Receptors and signaling

Question 1

Example of juxtacrine signaling is

Answer 1

Ephrin

Question 2

Norepinephrine:
In muscle -
In pancreas -

Answer 2

Contract smooth muscle
Decrease insulin

Question 3

T/F: Antagonists lower the response of the cell

Answer 3

False. They cause no response(named above is inverse agonist)

Question 4

Ach … heart but … skeletal muscles
Epinephrine … airways but …skeletal muscles

Answer 4

relaxes, contracts
x2

Question 5

RTK…

Answer 5

1) Growth factors
2) Autophosphorylation
3) Must dimerize to do so
4) MAPK (important in cancer) pathway
- GRB2(SH2 domain), SOS, RAS(+GTP), RAF-1, MEK, ERK > nucleus for transcription

Question 6

RGC…

Answer 6

Membrane-bound:
1) ANP, BNP, CNP
2) Single-pass
3) cGMP - PKG

Soluble:
1) NO (activated by Ach, bradykinin, substance P, Ca2+)
- Ca2+ > NO synthase
2) Treat angina pectoris, NT, macrophage/neutrophils destroy invaders
3) Sildenafil(inhibits PDE > increase cGMP and relaxation of vessels), REVATIO(blocks PDE for pulmonary hypertension)

Question 7

RTK associated…

Answer 7

1) Must dimerize
2) JAK/SRC
3) JAK cross-phosphorylate each other > receptor phosphorylates > STAT > nucleus for transcription

Question 8

Ser/Thr kinases…

Answer 8

1) TGF-B
2) Ligand binds type II then type II bring type I’s together and phosphorylate.

Question 9

RTP…

Answer 9

1) CD45 at T, B lymphocytes
2) CD45 dephosphorylated > activates LCK FYN > they phosphorylate other proteins

Question 10

Tyrosine phosphorylated by… and dephosphorylated by…

Answer 10

TK, Phosphotyrosine phosphatase(PTP)

Question 11

GPCR…

Answer 11

1) 7 membrane-spanning alpha helices(5-6 bind)
2) alpha and B-Y of G-protein both have effects
3) alpha G has GTPASE activity to shut off

Question 12

cAMP pathway…

Answer 12

1) Gs of @G activates AC
2) ATP > cAMP(In cortex aldosterone and cortisol secretion, in kidney water retention)
3) PKA
4) PDE = cAMP > AMP
Caffeine, Theophylline inhibits PDE
Epinephrine in fat cells: triglyceride breakdown
Epinephrine in the liver: glycogenolysis/gluconeogenesis

Question 13

DAG, IP3 pathway…

Answer 13

1) Gq activates PLC
2) PIP2 = IP3 + DAG
3) DAG > PKC
4) IP3 opens Ca2+ channels on ER > PKC

Question 14

COX:
Lipoxygenase:
Epoxygenase:
Function?

Answer 14

1) Thromboxanes, prostaglandins, prostacyclins
2) 5-HETE, leukotrienes
3) HETE’s, EET’s
Vasoactive, platelet action, modulate ion transport
Blood vessels, inflammation

Question 15

NSAID’s are… They…Inhibit…

Answer 15

1) non-steroidal anti-inflammatory drugs
2) Relieve pain, fever, inflammation
3) PLA2

Question 16

What receptors have no ligands?

Answer 16

Orphan receptors

Question 17

Nuclear receptors are 2 types
What does each bind?

Answer 17

Heterodimeric: Retinoic acid, Vit, thyroid hormones
Homodimeric: Steroids