14. Cell signalling and signal transduction (II)

Question 1

Types of cell surface receptors

Answer 1

1. Ion-channel-coupled receptors
2. G-Protein-coupled receptors
3. Enzyme-coupled receptors

Question 2

1. Ion-channel-coupled recptors

Answer 2

• ions
• signal molecule
• plasma membrane
• cytosol

Question 3

2. G-protein-coupled recptors

Answer 3

• > largest family of cell surface receptors
• > large extracellular (EC) domain which binds the protein ligand
• > 700+ in humans
• > 7 membrane spanning domains
• > all signal via G-proteins

=> over 1/3 of all known drugs act upon GPCRs or the pathways they activate

GTP-binding proteins (G proteins) -> Trimeric aβγ

Question 4

Four forms of Intercellular signalling

Answer 4

A) Contact dependent
B) Paracrine
C) Synaptic
D) Endocrine

Extracellular signal molecules binds to specific receptors

Extracellular signal molecules can act over either short or long distances