Introduction to Signal Transduction

1
Lecture 13

• Introduction to Signal Transduction

2
Types of Biosignaling
3
Signal Transduction
Extracellular ligand
Phosphorylation/dephosphorylation
Activation of enzymes
4
Receptor ligand interactions
5
Scatchard analysis
6
Amplification of signal
Hormone in bloodlt10-8 M
7
Second messengers
8
More second messengers
Ca 2
9
Glucagon and Epinephrine
Glucagon Epinephrine

• Response to stress
• 2nd messengercAMP

• Response to low blood sugar
• 2nd messenger cAMP
• Peptide(29 amino acids)

10
An adenylate cyclase cascade
11
Protein kinase A
Phosphorylates Phosphorylase b kinase
12
Turning of the signal
Cyclic AMP degradation
13
Turning off the signal
At the G protein
14
Turning the signal off (at receptor)
15
Turning off the receptor
16
Diseases that affect G-proteins Cholera and
Pertussis