Revised curriculum

1. Revised curriculum (1) December 16 (Tuesday) Second messengers (2) December 18 (Thursday) Protein kinases and cancers (3) December 23 (Tuesday) Protein phosphatases and diseases (4) December 25 (Thursday) Literature study I (5) December 30 (Tuesday) Literature study II Tzu-Ching Meng tcmeng@gate.sinica.edu.tw 27855696 ext 6140 or 6141

2. Assigned reading for literature study I

3. Assigned reading for literature study II

4. Lecture I Basic concept of cell signaling and second messengers Reference: Lodish et al., Molecular Cell Biology 6th edition (2007), Chapters 15 and 16 December 16, 2008

5. Unit A signals System Unit C Unit B Input signal Output signal Cell Cell as information processing unit

6. General principles of signaling by cell-surface receptors • Synthesis and (2) release of signaling • molecules by the signaling cells; • (3) Transport of the signal to the target cells; • (4) Binding of the signal by a specific • receptor protein; • (5) Initial of intracellular signal transduction • pathways; • (6) Specific changes in cellular functions; • (7) Inactivation of the receptor; • (8) Removal of signaling molecules

7. Signaling molecules can act locally or at a distance

12. Two modes of intracellular signaling transmission • Low molecular weight messenger substances– second messengers • Protein-protein interaction Overview of major classes of cell surface receptors 2nd messengers

13. Relationship between ligand and receptor— G protein coupled receptors

14. General structure of G protein coupled receptor

15. Operational model for ligand-induced activation of effector protein associated with G protein coupled receptors

17. Overview of major classes of cell surface receptors Protein-protein interaction

18. Relationship between ligand and receptor— Receptors that activate intracellular enzymes

19. Overview of major classes of cell surface receptors Protein-protein interaction Proteolytic process

20. Relationship between ligand and receptor— Receptors that trigger intracellular proteolysis pathways

21. Relationship between ligand and receptor— Receptors that function as ion channel upon ligand binding

22. A distinct class of receptors— Receptors that are located intracellularly, but ligands may be generated either extracellularly or intracellularly

23. Second messengers • Characteristics of second messengers: • Diffusible signaling molecules; • Rapidly produced/activated and rapidly degraded/inactivated; • May be stored intracellular in certain organelles; • Can be produced in a location-specific manner. • Two types of second messengers: • Hydrophilic– cAMP, cGMP, inositol phosphates (IPs), Ca2+, NO; • Hydrophobic– diacylglycerol (DAG), • phosphatidyl inositol phosphates (PIPs).

24. Four common 2nd messengers

25. Mammalian adenylyl cyclase is a membrane-bound enzyme with two catalytic domains and two integral membrane domains, each of which contains 6 transmembrane a-helices.

26. 3-D structure of Gsa-GTP complexed with two catalytic domains of adenylyl cyclase One subunit of trimeric G protein

27. Hormone-induced activation or inhibition of adenylyl cyclase in adipose cells Gs stimulation Gi inhibition

28. Typical amplification of an external signal downstream from a receptor Extracellular stimulus Effector Intracellular 2nd messenger Effector

29. The membrane A kinase-associated protein (mAKAP) anchors both PKA and cAMP phosphodiesterase (PDE) to the nuclear membrane, forming a feedback loop that provides close local control of the cAMP level • Basal level of PDE activity keeps [cAMP] low; • Activation of receptor causes an increase in [cAMP]binding of cAMP to PKA; • Activated PKA (C) phosphorylates and activates PDE, driving [cAMP] low; • Dephosphorylation of PDE returns the complex to the resting state.

30. Synthesis of DAG and IP3 from membrane-bound phosphatidylinositol Key enzyme 1 Key enzyme 2 Key enzyme 3 All membrane-bound

31. IP3/DAG pathway triggered by ligand binding to GPCRs for elevation of Cytosolic Ca2+ and activation of PKC

32. Second messenger nitric oxide (NO) is produced by intracellular NO Syntheases (NOSs) NADP NADPH nNOS (NOS1) L-citrulline iNOS (NOS2) L-arginine eNOS (NOS3) O2 NO. NO synthases NO is generated in most cell types by NO synthases. nNOS: neuronal NOS iNOS: inducible NOS eNOS: endothelial NOS

33. Guanylyl cyclase is a typical intracellular receptor of NO NOS NO/cGMP- dependent pathways L-arginine NO + citrulline guanylyl cyclase GTP cGMP cGMP-regulated Phosphodiesterases (PDE) Protein kinase G cGMP-regulated Ion channels Smooth muscle relaxation, platelet inhibition , cell growth and differentiation

34. Regulation of contractility of arterial smooth muscle by NO and cGMP

35. ROS= Reactive Oxygen Species

36. Reactive oxygen species (ROS) function as second messengers in cells UV, Ionizing Irradiation Peptide Growth Factors Ligands for GPCRs Cytokines H2O2 Nox ROS ROS ROS ? Activation of Tyr(P) signaling Transformation Signaling Mitogenic Signaling

37. Assigned paper for the Literature Study I Huang et al (2007) Positive regulation of Itk PH domain function by soluble IP4. Science, 316, p. 886 Reference article: Irvine R. (2007) Cell signaling: the art of the soluble. Science, 316, p. 845