Cell Signalling

Question 1

How does G protein linked receptor work?

Answer 1

1. A ligand recognises and binds to the specific ligand binding site on GPLR w a complementary 3D conformation.
   .
   - This triggers a conformational change and activates GPLR. The cytoplasmic side of GPLR is now complementary to the 3D conformation of G protein
   __________________________[_________
   .
2. Inactive G protein recognises and binds to the intracellular domain of GPLR.
   .
   - G protein exchanges its bound GDP for GTP, activating the G protein.
   __________________________[_________
   .
3. Active G protein dissociates and binds to adenynyl cyclase
   .
   - Adenynyl cyclase is **activated** and coverts many ATP to cAMP (cyclic AMP)
   .
   - Cytosolic concentration of cAMP 2nd messengers increases
   __________________________[_________
   .
4. cAMP transmit signal to relay proteins /protein A molecules
   .
   - The last molecule of the signal transduction results in a cellular response

Question 2

struc to function receptor tyrosine kinase

Answer 2

1. Transmembrane region has many hydrophobic amino acids
   - Have hydrophobic interactions with the hydrophobic core of the phospholipid bilayer
   __________________________[_________
   .
2. Intracellular tyrosine kinase tails have may tyrosine residues
   - Allow tyrosine residues to be phosphorylated
   __________________________[_________
   .
3. Extracellular binding site and intracellular domain which are hydrophilic
   __________________________[_________
   .
4. Intracellular tyrosine kinase tails have may tyrosine kinase domains
   - to phosphorylated tyrosine residues

Question 3

struc to function GPLR

Answer 3

1. (7 hydrophobic a-helices) Transmembrane region has many hydrophobic amino acids
   - Have hydrophobic interactions with the hydrophobic core of the phospholipid bilayer
   __________________________[_________
   .
   2.

Question 4

Mode of action of RTK