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Flashcards in Biochem Deck (27):
1

epinephrine (adrenaline)

receptor = GPCR(g-protein coupled receptor)

2

cortisol hormone

intracellular receptor

3

estradiol hormone

intracellular receptor

4

glucagon hormone

GPCR

5

growth hormone

tyrosine kinase-associated receptor

6

Insulin (hormone)

Receptor Tyrosine Kinase

7

Testosterone

Intracellular receptor

8

Epidermal Growth Factor (EGF)

Receptor tyrosine kinase (RTK)

9

platelet-derived growth factor (PDGF)

receptor tyrosine kinase (RTK)

10

Nerve growth factor (NGF)

Receptor tyrosine kinase (RTK)

11

Transforming growth factor-B

Serine/threonine receptor kinase

12

Nitric oxide (NO)

*permanently* binds guanylyl cyclase

13

Acetylcholine (ACh)

GPCR

14

Hormones that act on GPCRs

Epinephrine, glucagon, Acetylcholine

15

Hormones that bind to intracellular receptors

- cortisol, estradiol, testosterone, Thyroid hormone (T3/Thyroxine), Vitamin D3

16

hormones that bind to RTKs (receptor tyrosine kinases)

- insulin, EGF (epidermal growth factor), PDGF (platelet-derived GF), NGF (nerve GF)

17

s and i GPCR signaling

Effector: adenylyl cyclase
2nd mess: cAMP (S - up, I- down)
Receptors: S - beta Adrenergic, glucagon, serotonin, vasopressin RsI - alpha adrenergic, Ach Rs

18

q GPCR signaling

effector: PLC
2nd mess: IP3, DAG
Receptor: Ach (o)

19

t GPCR signaling

effector: cGMP phosphodiesterase
2nd mess: cGMP (down)
Receptor: rhodopsin

20

NO synthesis

substrate: argenine
product: citrulline and NO
3 NO synthases:
- Neuronal Constitutive NOS (nNOS)
- Endothelial constitutive NOS (eNOS): in smooth mm.
- Induced NOS (iNOS): in macrophages

21

Phospholipase C cascade

initiated by RTK,
activates Phosphoinositide (PI) pathway (w/ GPCRs)
--> increase cytosolic Ca2+ levels
(boost signaling w/ Ca2+)
** directly makes DAG and Ins-1,4,5-P3

22

Receptor Tyrosine Kinase (RTK) mech

set of 2 Rs on 2 intracellular proteins w/ tyrosine kinases.
Activate when ligands bind --> auto-phosphorylate and dimerize.
ligands: EGF, FGF, insulin (growth factors!)
pathways activated: Src, Phospholipase C, MAP kinase, PI-3K

23

Insulin Receptor Substrate ("IRS")

Insulin-specific receptor that binds to RTK (when RTK = activated),
=> docking station for mTOR, AkT, and MAPK

24

AC (adenylyl cyclase) pathway

AC --(activate)--> cAMP,
2 cAMP --(activate)--> PKA --> (phosphorylate target proteins or cAMP Response Element ""CREBP"")

25

protein kinase C

family of ser/thr kinases,
used in signaling cascades to phosphorylate target molecs.
(activated by DAG&Ca2+ from GPCRS, cGMP from NPRs)
promote cell proliferation

26

Major cell cycle checkpoints
(4)

1. restriction point (end of G1): to divide or not to divide?
2. S phase checkpoint: is DNA is damaged, and not fixable?
3. G2/M checkpoint: is replication completed?
4. Spindle assembly checkpoint (M): are chromatids properly arranged on spindles?

27

Clinical disease assoc. w/ problems with heme synth pathway...
- ALA synthase
- a-ALA dehydratase
- uroporphyrinogen I synthase
- uropophyrinogen decarboxylase

1. ALA synthase (EtOH, barbituates, hypoxemia) => anemia
2. ALA dehydratase (Lead toxicity) => Bx changes...
3. Uroporphyrinogen I synthase (Acute intermittent pophyria) => urine darkens on standing
4. Uroporphyrinogen decarboxylase (Porphyria cutanea tarda) => photosensitivity