25_Signal Transduction III

Question 1

Where in a phospholipid does PLC cleave?

Answer 1

between the glycerol and the phosphate

Question 2

What is the domain on PLC that interacts with a phosphorylated inositol ring?

Answer 2

PH domain 
(pleckstrin homology domain)

Question 3

In the example of Ach-induced smooth muscle contraction, what triggers generation of phosphorylated lipids at the membrane?

Answer 3

activation of the GPCR

Question 4

In the example of Ach-induced smooth muscle contraction, what phosphoinositide does PLC use as a substrate? What are the two 2nd messengers produced?

Answer 4

PI(4,5,)P2

2nd messengers: IP3 and diacyl glycerol (DAG)

Question 5

Where does IP3 bind?

Answer 5

IP3 receptors on the sarcoplasmic reticulum

Question 6

Which ion’s release is triggered by IP3?

Answer 6

Ca2+

Question 7

What does DAG activate?

Answer 7

a protein kinase-C cascade

Question 8

What are the second messengers involved in smooth muscle contraction?

Answer 8

IP3 & Ca2+

DAG (although exact function of DAG on cellular level is unclear)

Question 9

Why is a wave of calcium observed in mammalian eggs upon fertilization?

Answer 9

IP3 is formed by a PLC brought into the egg by the sperm

Question 10

What is an example of a compound used to visualize calcium in a living cell?

Answer 10

Fura2

Question 11

What second messengers are required for chemotaxis?

Answer 11

IPs

Question 12

What is the effector protein in the IP3 production pathway?

Answer 12

PLC