Lecture 15 Signal Transduction Part 2

Question 1

Phosphorylation

Answer 1

addition of phosphate group to a molecule, usually a protein

Question 2

Protein kinases are enzymes that are the effectors of __________ and catalyze the _____________ from ATP to specific acids on proteins

Answer 2

phosphorylation, transfer of phosphate group

Question 3

Proteins are phosphorylated primarily on what residues?

Answer 3

Serine, Threonine and tyrosine.

Question 4

Give 3 examples of serine and threonine kinases.

Answer 4

PKA, PKC, CaMKII

Question 5

What are protein phosphatases and what do they do?

Answer 5

cleave phosphate from target molecule–dephosphorylate

Question 6

Binding of the second messenger removes _________ and allows catalytic domain to be activated.

Answer 6

autoinhibition

Question 7

What do catalytic subunits do?

Answer 7

transfer phosphate group to target proteins

Question 8

Catalytic subunits are being kept inactive by __________

Answer 8

regulatory subunits (autoinhibition)

Question 9

Many kinases are regulated by ___________ in the activation loop.

Answer 9

phosphorylation

Question 10

Name the steps to the phosphorylation of the ERK2 activation loop

Answer 10

Phosphorylation on threonine and tyrosine
Phospho-thr 183 contacts alphaC and promotes active confirmation
Phospho-thr183 promotes ERK2 dimerization via changes in c terminal extension

Question 11

Break time! https://www.youtube.com/watch?v=PPQNbTPb-F0

Answer 11

:)

Question 12

Name the 4 stimuli that kinases can be activated by.

Answer 12

CaMKII (calcium)
PKC (lipids and calcium)
TRKS (ligands)
PDK1/AKT (lipids)

Question 13

__________ by binding to the regulatory subunits and causing them to release active catalytic subunits.

Answer 13

cAMP activates PKA

Question 14

Catalytic subunits phosphorylate _______ and ________ residues of target proteins.

Answer 14

serine, threonine

Question 15

Phosphorylation usually results in ________ of the substrate protein.

Answer 15

activity change

Question 16

When cAMP concentration rises, it binds on the 2 regulatory subunits, which leads to release of catalytic subunits. These then transfer ATP to protein substrates and serine threonine. What activation cycle is this describing?

Answer 16

PKA activation

Question 17

Downregulation of PKA occurs by a feedback mechanism. What is this mechanism called and what’s its function?

Answer 17

PDE, converts cAMP to AMP, reducing cAMP that can activate PKA, therefore, PKA is controlled by cAMP

Question 18

_____ causes PKC to move from cytosol to the membrane where it binds calcium and another phospholipid.

Answer 18

DAG

Question 19

What process relieves autoinhibition, enabling PKC to phosphorylate proteins?

Answer 19

the DAG process

Question 20

________ link DAG and calcium signals to downstream targets.

Answer 20

PKS isoforms

Question 21

Calmodulin activates CaMKII by doing what?

Answer 21

displacing inhibitory domain from the catalytic subunit.

Question 22

Describe the induction and early phase of mechanisms underlying LTP?

Answer 22

Rise in postsynaptic Ca2+ and acts as 2nd messenger, activating CaMKII and PKC

Question 23

Maintenance of LTP is due to insertion of ______ into the postsynaptic membrane.

Answer 23

AMPA-Rs (causes increased response to glutamate)

Question 24

MAPK regulate what and why are they special?

Answer 24

gene expression, they are kinases that are regulated by other kinases.

Question 25

Changes in gene expression and protein synthesis brought about by the persistent activation of protein kinases activated during early LTP is known as what?

Answer 25

Late LTP

Question 26

Break time!

https://www.youtube.com/watch?v=U-aVkMClvBs

Answer 26

:)

Question 27

Upon activation, ERK phosphorylates ________ leading to synthesis of new proteins.

Answer 27

transcription factors (BREB)

Question 28

Protein phosphatases are the primary effectors of dephosphorylation. What to they act in opposition to?

Answer 28

Act in opposition to protein kinases.

Question 29

T/F: Kinases add phosphates and phosphotases remove them

Answer 29

True

Question 30

T/F: Several proteins use the same phosphorylation sites for activation and inhibition.

Answer 30

False, they have separate sites.

Question 31

What allows for PNA polymerase to assemble on DNA promotor region and to begin transcription?

Answer 31

transcription factors

Question 32

In RNA polymerase activity: activators ________ and repressors _________ gene expression.

Answer 32

enhance, decrease

Question 33

CREB binds to what to increase/decrease transcription of genes?

Answer 33

cAMP response elements

Question 34

T/F: CREB is normally unphosphorylated. Its phosphorylation potentiates transcription

Answer 34

True