1. Adenylyl Cyclase Overview/Structure

2. What does it do?

3. Overview- General Structure Lyase Enzyme that converts ATP to cAMP Interacts with g proteins and receptors 1064-1353 amino acids long 120-150 kilodaltons

4. General Structure cont’d 10 mammalian isoforms –All membrane bound –60% similarity –50%-90% in cytoplasmic regions

5. Primary Structure The main structural features of mammalian adenylyl cyclases M1/M2: 2 sets 6 transmembrane spans C1a/C1b: large cytoplamic domains (360-390 amino acids) C2a/C2b: large cytoplasmic domains (255-330 amino acids) –Most highly conserved sequence in all isoforms –50% similar; 25% identical N terminus and C terminus

6. Primary Structure Topology

7. Secondary Structure Alpha helices Beta sheets

8. Tertiary Structure The folding of a protein into a 3-D structure

9. Quaternary Structure Interaction between two domains Large cytoplasmic domains –C1a –C2b

10. Quaternary Structure Adenylyl cyclase interaction with G protein

11. Adenylyl Cyclase Function

12. Overview Signal Transduction -produces cyclic AMP from ATP -responds to a large number of receptors 10 Isoforms -allows a diverse response to the same or similar signals

13. Overview sAC is the tenth form of AC. It is soluble and only found in sperm

15. Forskolin Activation Forskolin - increases affinity - increases stability - enhances activity

16. Activation

19. Catalysis Mechanism ATP → cAMP +PP i → + ATP cAMP pyrophosphate

20. Catalysis Mechanism

22. Role of Cyclic AMP Step 1: activates protein kinases Step 2: protein kinases phosphorylate substrate proteins Step 3: activated substrate proteins regulate hormone production

23. Adenylyl Cyclase Regulation

24. GDP GTP RECEPTOR ADENYLYL CYCLASE

25. Regulation by Receptors Alpha-adrenergic receptors: - Stimulate Gi Proteins Beta-adrenergic receptors: - Stimulate Gs Proteins G Protein Coupled Receptor

26. G PROTEIN REGULATION (Guanine Nucleotide-Binding Protein)

27. ADENYLYL CYCLASE BINDING

28. Ca 2+ Regulation Site

29. CALCIUM/CALMODULIN CA 2+ ions CALMODULIN

31. PKC ( Protein Kinase C)

32. References The University of Oklahoma College of Medicine. Human Physiology Animations Page http://w3.ouhsc.edu/human_physiology/presentation/cyclaseani.gif (movie) http://w3.ouhsc.edu/human_physiology/presentation/cyclaseani.gif Western Kentucky University: Advanced Molecular Genetics http://bioweb.wku.edu/courses/ biol566/Images/gp009.jpg (both primary pics) Saint Edward’s University. Structure of G-Proteins and Adenylyl Cyclases. http://www.cs.stedwards.edu Hanoune, Jacques, et al. Adenylyl cyclases: structure, regulation and function in an enzyme superfamily. Molecular and Cellular Endocrinology 1997: (128) 179-194. Tang, Wei-Jen and James Hurley. Catalytic Mechanism and Regulation of Mammalian Adenylyl Cyclases. Molecular Pharmacology 1998: (54) 231-240. Sunahara, Roger et al. Complexity and Diversity of Mammalian Adenylyl Cyclases. Annual Review of Pharmacology Toxicology 1996: (36) 461-480. Cann, Martin. Bicarbonate Stimulated Adenylyl Cyclases. Life 2004: (9) 529-534.