Cellular Signaling

1. Cellular Signaling Montarop Yamabhai Suranaree University of Technology

2. Out line • Principle ofCellular Signaling • Nuclear Receptor • G Protein-Couple Receptors (GPCR) and Second Messengers • Receptor Tyrosine Kinases • Other Signaling Pathway • Interaction and Regulation of Signaling Pathway • Target intervention in Signal Transduction

3. I. Principle of cellular signaling • Extracellular signal molecules bind to specific receptors • There are two types of receptors • There are 5 types of intercellular signaling • Identification and purification of cell surface receptor • Responses from cellular signaling • There are three majors classes of cell-surface receptor • Multiple steps of cell signaling • Different types of intracellular signaling proteins • Methods that are used to study protein-protein interaction

4. There are two types of receptors:

5. Ligands that bind to intracellular receptors

6. Ligands that bind to cell surface receptors • Water soluble hormone and neuro transmitters • Peptide hormones • Small charged hormones and neurotransmitters • Prostaglandin and other eicosanoid hormones

7. Small molecules that function as neurotransmitters

8. Eicosanoid hormones

9. 5 Types of Intercellular Signaling • Endocrine signaling • Paracrine signaling • Synaptic signaling • Autocrine signaling • Signaling by plasma membrane-attached proteins

10. Identification of cell surface receptor

11. Purification of cell surface receptor

12. Basic Components and Responses of Cellular Signaling Chage in ion permeability Activation/ repression of DNA/RNA synthesis

13. 3 Types of Cell-Surface-Receptors • Ion-channel-linked receptors • G-protein-coupled receptors • Enzyme-linked receptors

14. Multi steps of signaling pathway • Recognition of stimulus by cell surface receptor • Transfer of signal across plasma membrane • Transmission of the signal to specific targets inside the cells • Cessation of the responses

15. Types of Signaling Protiens • Proteins Kinases / Phosphatases. These are proteins that involve in phosphorylation reactions • Proteins or GTP-binding proteins • Adaptor and scaffold proteins

16. Protein Kinases & Phosphatases Final Target

17. G-Protein Accessory proteins 1. GTPase-activating proteins (GAPs) 2. Guanine nucleotide-exchange factors (GEFs) 3. Guanine nucleotide-dissociationinhibitors (GDIs)

18. Adaptor Protein

19. Scaffold Proteins

20. Detection of Protein-Protein Interaction by Yeast two-hybrid system

21. Detection of Protein-Protein Interaction by Phage Display Technology

22. Nuclear Receptor(Ligand-activated Gene Regulartory Protein)

23. Responses induced by the activation of a nuclear hormone

24. G Protein-Couple Receptors (GPCR) and Second Messengers • Structure and Function of G protein-couple receptor • Second messengers • The specificity of G protein-coupled responses • The role of G-protein-coupled receptors in sensory perception

25. G protien-coupled receptor Seven membrane spanning a helices G protein binds to guanine nucleotides, either GDP or GTP. It consists of three different polypeptide subunits, called a, b, and g.

26. Mechanism of activation of GPCR • activation of the G protein by the receptor • Activation of adenylate cyclase to generate cAMP • Activation of phospholipase Cb to generate IP3 and DAG • relay of the signal from G protein to effector • ending of the response

27. I. Activation of the G protein by the receptor

28. II. Relay of the signal from G protein to effector

29. III. Ending of the response

30. The synthesis and degradation of cAMP

31. b-adrenergic receptors mediate the induction of epinephrine-initiated cAMP synthesis • Agonist and of the • b-adrenergic receptors • Epinephrine • isoproterenol • Antagonist of the • b-adrenergic receptors • Alprenolol • Propranolol • Practolol

32. Hormone-induced activation and inhibition of adenylate cyclase

33. Activation of cAMP-dependent protein kinase (PKA) by cAMP

34. Table 1

35. A sample of known PKA substrates • Muscle glycogen synthase (Ia) • Phosphorylase kinase a • Protein phosphatase-1 • Pyruvate kinase • CREB • Liver tyrosine hydroxylase • Acetylcholine receptor d • Protein phosphatase inhibitor -1 • S6 ribosomal proteins • Rabbit heart troponin • Hormone sensitive lipase • Phosphofructokinase • Myosin light-chain kinase • Fructose biphosphatase • Phosphorylase kinase b • Musle glycogen synthase • Acetyl CoA carboxylase

36. A variety of responses from cAMP signaling • Plasma membrane: transport • Microtubule: assembly and disassembly • Endoplasmic recticulum: protein synthesis • Nucleus: DNA synthesis, gene expression • Mitochondria and cytosol: glycogen break down (phosphorylase) in liver, glycogen synthase, triglyceride lipase (fatty acid formation in fat cells

38. Activation of gene transcription by a rise in cAMP

39. Regulation of glycogen breakdown and synthesis by cAMP in liver and muscle cells

40. The role of cAMP in glucose metabolism in liver cells

41. Amplification of the signal via cAMP signaling pathway

42. The generation of phosphatidyl inositol-derived second messengers

43. Protein Kinase C (PKC) is activated by inositol phospholipid pathway

45. Elevation of Ca2+ via the inositol lipid signaling pathway

46. Table 20-4. Cellular Responses to Hormone-Induced Rise in Inositol 1,4,5-Trisphosphate (IP3) and Subsequent Rise in Cytosolic Ca2+ in Various Tissues

47. Ca2+ Calmodulin mediates many cellular responses

48. The specificity of G protein-coupled responses • GPCRs link to different G protein • G protein regulate different effector proteins

49. Table 20-5. Properties of Mammalian G Proteins Linked to GPCRs Ga Subclass Effect Associated Effector Protein 2nd Messenger Gs Adenylyl cyclase cAMP Ca2+ channel Ca2+ Na+ channel Change in membrane potential Gi Adenylyl cyclase cAMP K+ channel Change in membrane potential Ca2+ channel Ca2+ Gq Phospholipase C IP3, DAG Go Phospholipase C IP3, DAG Ca2+ channel Ca2+ Gt cGMP phosphodiesterasec GMP Gbg Phospholipase C IP3, DAG Adenylyl cyclase cAMP

50. The specificity of G protein-coupled responses