Signal Transduction Flashcards Preview

Medical Biochemistry > Signal Transduction > Flashcards

Flashcards in Signal Transduction Deck (34):
1

what are examples of intercellular signals?

endocrine -- hormones, insulin, glugagon, epi, steriods, peptide
Autocrine - eicosanoids
Paracrine - NTs, GFs, NO, neuron signaling, contact signaling

2

what are the 4 basic types of receptor-mediated signal transduction -- extracellular signals producing intracellular signals

1. steroid receptor
2. Gated-ion channel
3. Receptor enzyme (catalytic receptor)
4. G-protein coupled receptor (GPCR)

3

what are examples of steroid receptor molecules?

testosterone, estrogen, cortisol,
Vit. D and retinoic acid (vit. A)
thyroid hormone
aldosterone

4

what do steroid receptor molecules do?

penetrate cellmembrane and bind to intracellular receptors
hydrophobic/lipophilic
induce up regulating gene expression at the level of DNA transcription and gene enhancment

5

which is the slowest signal transaction?

steroid receptor

6

what are zinc finger motifs?

binds to specific sequence of bases in major groove of DNA - has alpha helix, beta sheet and cystein, histidine and zinc idk?

7

what are examples of gated ion channel molecules?

nicotinic Ach receptors of muscle or nerve
gamma aminobutyric acid (GABA) and glycine receptors in CNS

8

what is an example of receptor enzymes molecules?

insulin receptor = tyrosine kinase

9

what are the intracellular effectors of receptor enzyme ?

IRS (insulin receptor substrates 1-4)
adaptors
enzyme effectors

10

what are the cellular responses of Insulin receptor (receptor enzymes)?

increased glucose uptake
regulation of transcription of certain proteins
activation of enzymes

11

how are the enzymes activated in insulin receptor tryosine kinase?

covalent modification - phos/ dephos,
upregulation(increase synthesis of enzymes)

12

what are beta subunits?

tyrosine kinases

13

what happens after the tyrosine kinase domains of the insulin receptor are activated by insulin?

interchain autophosphorylations - phosphates are added

14

what are examples of GPCR and intracellular second messengers?

adenylate cyclase system (cAMP)
calcium/phosphotidylinositol system (IP3, DAG, and Ca2+)
protein kinase A

15

what are examples of intracellular second messengers?

cAMP
IP3, DAG, ca2+
cGMP
NO

16

what inhibits phosphodiesterase (the enzyme that converts cAMP to 5' AMP?

caffiene and theophyllin

17

cAMP activated protein kinase A, but what does PKA do?

phosphorylates target proteins

17

cAMP activated protein kinase A, but what does PKA do?

phosphorylates target proteins

18

what is a leucine zipper?

cause dimerization
example - cAMP responsive element binding protein (CREB) ahs leucine zipper motif

18

what is a leucine zipper?

cause dimerization
example - cAMP responsive element binding protein (CREB) ahs leucine zipper motif

19

what does ADP-ribosylation of G alpha result in?

inactivation of the GTP-ase activity

19

what does ADP-ribosylation of G alpha result in?

inactivation of the GTP-ase activity

20

what do cholera toxin and E coli both do to Gs?

ADP ribosylations

20

what do cholera toxin and E coli both do to Gs?

ADP ribosylations

21

what does pertussis toxin do to Gi?

ADP-ribosylation

21

what does pertussis toxin do to Gi?

ADP-ribosylation

22

what does PKC require for max activity?

phopholipids, calcium and DAG

22

what does PKC require for max activity?

phopholipids, calcium and DAG

23

what is the G alpha subunit for cAMP system?

beta-adrenergic or glucagon

23

what is the G alpha subunit for cAMP system?

beta-adrenergic or glucagon

24

what G alpha subunit is used to inihibit cAMP?

alpha 2-adrenergic

24

what G alpha subunit is used to inihibit cAMP?

alpha 2-adrenergic

25

what G lpha subunit is used to activate phospholipase C?

alpha 1 adrenergic

25

what G lpha subunit is used to activate phospholipase C?

alpha 1 adrenergic