1. Signal Transduction Pathways
An introduction to Information metabolism
Chapter 15 Stryer Biochemistry

6. Signal Transduction 1) Membrane receptors transfer information
2) Second messengers relay information from the receptor ligand complex.
3) Protein phosphorylation is a common means of information transfer

7. Second messengers

8. Second messengers

9. Second messengers

10. Second messengers

11. Protein Phosphorylation

12. 7TM helix receptors
The 7TM helix receptors change conformation upon binding of ligand and activate a G-Protein
Rhodopsin
Β-adrenergenic receptor

25. Activated G-Protein transmits signal by binding to other proteins
G-Protein binding to adenylate cyclase increases the catalytic efficiency of the adenylate cyclase and increases the synthesis of cAMP inside the cell

27. G-Proteins spontaneously reset themselves
Resetting the G-Protein

28. Receptor resetting

29. cAMP stimulates the phosphorylation of many target proteins by activating PKA
1) Glycogen metabolism
2) Expression of specific genes (CREB)
3) Synaptic transmission
Serotonin binds to a 7TM helix receptor
cAMP activates PKA
PKA facilitates the closing of K channels by phosphorylation

30. Hydrolysis of Phosphatidyl inositol Bisphosphate

34. What are the biocehmical effects of IP3?
IP3 causes the rapid release of Ca from intracellular stores (ER, SR)
Causes smooth muscle contration
Glycogen breakdown
Vesicle release

36. Diacylglycerol activates PKC

40. Ca Ion is a ubiquitous cytosolic messenger

46. Ca activates the regulatory protein Calmodulin

48. Regulation of Calmodulin of Calmodulin kinase

52. Receptor dimerisation

59. JAK phosphorylates STAT5

60. Some receptors contain a tyrosine kinase domain within their covalent structures

65. Defects in signaling pathways can lead to cancer and other diseases