G Protein Couple Receptors

Question 1

5 Families of GPCR

Answer 1

• Rhodopsin
• Secretin
• Frizzle/taste
• Adhesion
• Glutamate

Question 2

G protein structure

Answer 2

3 subunits, alpha and gamma anchored to membrane

Question 3

GPCR- G protein interaction

Answer 3

alpha 5 helix o alpha subunit fits into a pocket of the TM regions opened up upon activation- non polar interactions. interaction of Tyr residues with Arg in E/DRY motif of receptor TM3.

Question 4

What is the limiting step of GTPase

Answer 4

GDP release

Question 5

Coverging pathways

Answer 5

Large number of diff receptors signal via a much smaller number of G proteins which in turn regulate an even smaller number of second messenger molecules

Question 6

Second Messenger

Answer 6

intracellular molecules that act to transmit signals from receptor to target

Question 7

What is G12/13 involved in

Answer 7

• Cytoskeletal changes
• Cell growth
• Oncogenesis

Question 8

What mediate G-protein independent signaling

Answer 8

beta arrestins which act as scaffolding proteins for other signaling molecules

Question 9

Class I defects

Answer 9

Loss of transcription

Question 10

Class II defects

Answer 10

mRNA instability, improper translation, retention in the ER

Question 11

Class III defects

Answer 11

retention in Golgi

Question 12

Class IV defects

Answer 12

Altered ligand binding, Altered signal transduction, altered internalization