1. Chapter 15- Cell Communication Part I- General signaling strategies Part II- G protein signaling Part III- Enzyme-linked cell surface receptors Part IV- Proteolysis-dependent signaling pathways

2. Outline A. Two cell types Part I- General signaling strategies B. A typical signaling pathway C. Most signaling molecules are hydrophilic (water loving) D. Some signaling molecules are hydrophobic (water hating) E. A review of membranes (from chapter 10) F. Signaling over short or long distances G. Autocrine signaling H. Cells respond to specific combinations of factors I. Signaling through gap junctions J. Different cells respond differently to the same signal molecules K. Nuclear receptors are ligand-activated gene regulatory proteins L. Three classes of cell-surface receptors M. Common features of G protein-linked and enzyme- linked receptors

3. Part II- G protein signaling B. Trimeric GTP-binding proteins (G proteins) relay the signal A. G protein-linked receptors C. Steps to activate a G protein D. cAMP-mediated transduction E. Examples of hormone-induced cell responses mediated by cAMP F. Some examples of phospholipase C-  cell responses- G. Overview of phospholipase C-  pathway H. We can activate these pathways with drugs I. Ca++ is a ubiquitous intracellular messenger J. G-protein linked receptors required for vision and smell K. How is a response desensitized? L. Summary PATHWAY 1 - cAMP PATHWAY 2- Phospholipase C- 

4. A. G protein-linked receptors ______ membrane proteins __% of C. nematode genes ~_____ G proteins used for _____ in mice Activated by ___________ __________,____________ B. Trimeric GTP-binding proteins (_______) relay the signal Three subunits-  1.Inactive state- a subunit bound with ______  and  subunits in one complex INACTIVE G protein Part II- G protein signaling

5. C. Steps to activate a G protein 1. Signal molecule binds ____________ 2. G protein _________ with receptor 3. GDP is replaced by _____ on  subunit 4.  proteins dissociate from  subunit Part II- G protein signaling

6. 5.  subunit binds to and ______ a ____________ 6. GTP on  subunit is _________ to _____ 7.  subunit __________ with  subunits Part II- G protein signaling

7. D. cAMP-mediated transduction 1. Signal molecule binds _________ 2. G protein interacts with receptor, ____ is replaced by ____, and  dissociate from  subunit 3. A subunit interacts with ___________________ 4. ____ is converted to ______ G protein is termed “__” in this pathway PATHWAY 1 - cAMP Part II- G protein signaling

8. What does cAMP look like?? 2. Note that ________ binds both __ and __ carbons of dATP ribose, hence the name “________” 1. ___________ produces ____ 3. cAMP ___________ breaks cAMP down to _______ This is the “Target” protein for the G- protein designated ___ PATHWAY 1 - cAMP Part II- G protein signaling

9. 5. cAMP binds ____________________ (PKA) PKA action likely accounts for all ___________ effects PKA is composed of _______________ subunits and _____ __________ subunits 6. Binding of cAMP causes active subunits to __________ and become “___________” PATHWAY 1 - cAMP Part II- G protein signaling

10. 7. Activated PKA is transported into ______________. 8. PKA_____________ CRE-binding protein (______). 9. CREB interacts with cofactor ____, which activates gene ____________. PATHWAY 1 - cAMP Part II- G protein signaling

11. cAMP induction by serotonin = High level cAMPRed = Moderate level cAMP Yellow = Low level cAMP Blue E. Examples of hormone-induced cell responses mediated by cAMP Muscle_______________________________ Heart ______________________________ Fat ______________________________ Ovary_________ __________ ____________________ Target tissue HormoneMajor response PATHWAY 1 - cAMP Part II- G protein signaling

12. PATHWAY 2- Phospholipase C-  F. Some examples of phospholipase C-  cell responses- Smooth muscle contraction, blood platelet aggregation, glycogen breakdown PI4,5-bisphosphate a. ______ 3. __activates phospholipase C-  4. phospholipase C-  breaks down _____ ____________ into: b. ___ a. ____ b. _____ Activates protein ________ Release of Ca++ from ___________ ____________ 1. Signal molecule binds receptor 2. G protein interacts with receptor, GDP is replaced by GTP, and  proteins dissociate from  subunit G protein is termed “__” in this pathway Part II- G protein signaling

13. ___ binds a IP3- gated __________ channel G. Overview of phospholipase C-  pathway ____activates protein kinase C (PKC) PATHWAY 2- Phospholipase C-  Part II- G protein signaling

14. H. We can activate these pathways with drugs a. DAG b. IP3__________________ _____________________ PATHWAY 2- Phospholipase C-  ______________ DrugEffect ____________ __________________ Ca++ release via a non-G protein pathway: __________ interaction Part II- G protein signaling

15. I. Ca++ is a ubiquitous intracellular messenger a. Free Ca ++ in cytoplasm is <____ M, Example- Nerve cells- _____________, influx of Ca++, secretion of ____________________ Part II- G protein signaling b. Extracellular is _____ M c. Ca ++ -_______ pumps Ca ++ out of cell and into ___

16. How is the Ca++ signal transduced?? Through ______________ 1. Ca++ binds ___________ 2. This complex binds ______________ 3. CaM kinases ______________ other proteins

17. If knock out _____________ in mice- Defect in ____________ where things are in _____ One CaM kinase is important in ____________ Part II- G protein signaling

18. J. G-protein linked receptors required for ______ and _______ Humans- distinguish >__________ distinct smells How?- by 1000s of __________ olfactory receptors (____) 1.________ binds receptor 2._____________ activated 3.________ produced 4.Gate opened 5.____ infux 6.Initiate __________ to brain ____________ also use G-proteins Termed “____“ Part II- G protein signaling operates through ______ production

19. K. How is a response _______________? ____, _____ or other G-linked receptor kinases (______) ______________the receptor ________ then binds the phosphorylated receptor GTP converted to ____ on  subunit IP3 __________________ Ca++ pumped ______ cAMP _____________ Mechanisms of inactivating responses Part II- G protein signaling

20. L. Summary G-protein linked receptors act through G proteins Gs Gq _______________________ ___________________ _____________ __________, __________ Golf________________________________ Gt__________ ____________ _____ _________ ___________ Target Enzyme G protein Molecule made Target PKC, PKA and CaM kinases all phosphorylate target proteins on________ or __________residues Part II- G protein signaling