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Flashcards in Signal Transduction Deck (54)
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1

What is signal tranduction

Way for signal from outside to affect function via amplification

2

Flow chart of tranduction

Signal ----- reception ---- transuction ----- response
Amplification from reception to transduction

3

Epinephrine binds

7 transmembrane domain protein known as a G-protein coupled receptor

4

G-protein coupled receptor that epinephrine binds to interacts with ____ and what does it do?

Heterotrimeric G protein that has 3 subunits
Will activate another enzyme

5

Epinephrine signaling pathway

Epinephrine binds B adrenergic receptor...G-protein phorphorylated and loses beta and gamma subunits...GTP with alpha unit binds to adenylate cyclase...adenylate cyclase converts ATP to cyclic AMP....cyclic AMP activates protein kinase A...PKA then phosphorylates serine residues on target proteins

6

Adenylate cyclase rxn

ATP ---- cyclic AMP

7

Cyclic AMP rxn

Protein Kinase A ------- activate protein Kinase A

8

Protein kinase A regulated by (what mechanism)

Autoinhibition

9

1st part of cAMP cascade termination

Epinephrine dissociates...bARK phosphorylates tail of receptor...this binds B-arrestin that blocks binding of new heterotrimeric proteins

10

bARK name and function

Beta-adrenergic-receptor kinase
Phosphorylates receptor using ATP to allow recruitment of B-arrestin

11

B-arrestin function

Blocks new heterotrimeric G-proteins from binding receptor

12

Second part of cAMP termination

GTP associated G-protein with adenylate cyclase undergoes hydrolysis to make GDP...beta and gamma subunits return and molecule dissociates

13

What happens to cyclic AMP during termination

Hydrolyzed by cyclic AMP phosphodiesterase to AMP

14

Cholera enzyme rxn

Catalyzes ADP-ribosylkation of G-protein alpha subunit

15

Cholera mechanism of disease

Internal GTPase is blocked and left in on state...overproduction of cAMP and PKA leads to membrane ion transport protein phosphorylation...loss of ions and water leads to diarrhea
Intestinal

16

Pertussis rxn

ADP-ribosylation of the heterotrimeric subunit (which is inhibitory)

17

Pertussis mechanism of disease

Blocks exchange of GTP for GDP and therefore heterotrimeric subunits with GDP remain off...adenylate cyclase, once on, is never turned off
Respiratory tract

18

Enzyme-linked receptors

Transduce an external signal across membrane by generating intramolecular enzymatic activity

19

Cytokine receptors

Receptor has NO intrinsic enzymatic activity and a second protein is activated by the binding of the cytokine or signaling agent

20

Cytokine receptors often activated

Jak-STAT signaling

21

Insulin receptor structure

Dimer with two extracellular alpha for binding pocket of insulin...each B subunit contains kinase omain

22

Binding of insulin results in

Cross-phosphorylation and activation of the receptor

23

Phosphorylated insulin receptor sites act as binding site ofor

IRS-1

24

IRS-1 allows binding of

PI-3K

25

PI-3K rxn

PIP2 ---- PIP 3

26

PIP3 function

Activates PIP 3-dependent kinase

27

PIP 3-dependent kinase function

phophorylates and activates kinases such as AKT

28

Insulin pathway

Receptor phosphorlates IRS...IRS binds PI3K...PI3K converts PIP2 to PIP3 via phosphorylation...PIP3 activates Pip3 dependent kinase...PIP3 dependent kinase phosphorylates AKT to activate it

29

insulin structures

Dimer linked by 2 disulfide

30

Type 1/2 diabetes onset, age, body, ketoacidosis

1 - sudden, any age, thin or normal, common
2 - gradual, adults, often obese, rare