cell signaling pathways

Question 1

what activates adenyl cyclase in the cAMP pathway

Answer 1

by a GTP-bound G protein subunit alpha, forming cAMP from ATP

Question 2

what does cAMP bind to release catalytic subunits

Answer 2

protein kinase A

Question 3

what degrades cyclic AMP

Answer 3

cAMP dependent phosphodiesterase

Question 4

what does the catalytic subunit from the cAMP pathway phosphorylate

Answer 4

transcription factor CRE binding protein (CREB) and cAMP response element CRE

Question 5

what is the last step of the cAMP pathway

Answer 5

specific genes expression occurs

Question 6

what activates the protein kinase domains of the dimerized receptor in the phospholipid calcium pathway

Answer 6

binding of a signal molecule

Question 7

what mediates the association of phospholipase C (PLC) γ with activated receptor tyrosine kinase

Answer 7

SH domain

Question 8

PLCγ catalysis of PIP2 leads to production of what

Answer 8

IP3 and DAG (diacylglycerol)

Question 9

what does diacylglygerol activate

Answer 9

protein kinase C

Question 10

what signals release of Ca from the intracellular storage sites

Answer 10

IP3

Question 11

what interacts with the Raf protein kinase

Answer 11

GTP binding protein Ras (rat sarcoma virus)

Question 12

1. what does Raf phosphorylate and activate.

2. what does that then activate

Answer 12

1. MEK (MAP kinase or ERK kinase)

2. ERK (extracellular signal regulated kinase)

Question 13

what does ERK do

Answer 13

phosphorylates the transcription factor for Elk-1

Question 14

what does Elk-1 binds SRE (serum response element) forming…..

Answer 14

SRF (serum response element) and then gene induction then occurs.

Question 15

in the JAK-STAT pathway, the JAK protein tyrosine kinase binds to the inactive factor STAT via what

Answer 15

SH2 domains

Question 16

what happens to STAT phosphorylation

Answer 16

it dimerizes

Question 17

what happens to the phosphorylated STAT dimer

Answer 17

translocates to the nucleus where it activates transcription of target genes

Question 18

in the NF-κβ transcription factor pathway, how is the inactive complex formed

Answer 18

NF-κβ association with inhibitory subunit I-κβ

Question 19

what happens when protein kinase C is stimulated

Answer 19

I-κβ is phosphorylated and undergoes degradation after ubiquitinization by the 26S proteosome

Question 20

what does I-κβ do

Answer 20

uncovers localization sites of NF-κβ, binds to DNA and regulates genes expression