L11- Cell communication 3

Question 1

What does DAG recruit to the membrane?

Answer 1

PKC- protein kinase C (a serine-threonine kinase)

Question 2

What does PKC do?

Answer 2

Phosphorylates/activates many target proteins-> amplification

Question 3

What else is needed to activate PKC?

Answer 3

Requires Ca2+. IP3 controls this intracellular Ca2+. Makes sure PKC only activateed when really needed.

Question 4

What is Ca2+ an example of?

Answer 4

A second messenger

Question 5

Summarise DAG and IP3 functions

Answer 5

DAG–> PKG

IP2–> Ca2+–> Kinases (PKC, CaMK)

Question 6

What can cAMP activate?

Answer 6

PKA

Question 7

How can PKA affect transcription?

Answer 7

1. Activation of PKA in cytosol
2. Translocation to nucleus
3. Phosphorylation of transcription factor
4. Increased transcription of target genes

Question 8

What is the largest group of enzyme coupled receptors?

Answer 8

Receptor tyrosine kinases RTKs

Question 9

How are RTKs activated?

Answer 9

By dimerisation

Question 10

What do Receptor tyrosine kinases (RTKs) do?

Answer 10

Phosphorylate- cause binding of specific signalling molecules to receptor tails.

Question 11

How are RTKs inactivated?

Answer 11

Dephosphorylation by tyrosine phosphatases and receptor internalisation. (endocytosis and degradation)

Question 12

Through which pathway does RTK regulate cell survival, proliferation and differentiation?

Answer 12

The MAP-kinase pathway

Question 13

What’s the MAP-kinase pathway activated by?

Answer 13

A monomeric G protein–> RAS

Question 14

Does Ras bind to RTK?

Answer 14

No. Ras binds to a MAP-kinase kinase kinase.

MAPKKK–> MAPKK–> MAPK–> regulates protein activity