1. Bio 110 Cell Communication Fotolia

2. For today Chapter 11 – Pages 206-217

3. How is the blueprint read? How is it regulated? How is it modified by drugs? How does it create an organism? How does it create disease?

4. WIkimedia Communication between cells is critical for gene regulation

5. Chemical Signals Chemical signals effect cell behavior in both beneficial and harmful ways Most medicines mimic or block endogenous cellular signals.

6. Cell Junctions Gap Junctions Plasmodesmata Cell-cell recognition Communication by Direct Contact

7. Paracrine signaling Local signaling Target cell Secretory vesicle Secreting cell Regulator diffuses through extracellular fluid Synaptic signaling Neurotransmitter diffuses across synapse Electrical signal along nerve cell triggers release of neurotransmitter Signals

8. Endocrine cell Blood vessel Target cell Hormonal signaling Long-distance signaling Signals Endocrine signals: internal, carried by bloodstream (only target cells are affected)

9. Human pheromones? Chemical Signals Long-distance signaling Exocrine signals: released to exterior of organism to communicate with other individuals (pheromones)

10. Human Embryo - Gray’s Anatomy De Carvalho et al., 2008 Int J Morphol Vestigial Vomeronasal (Jacobsen’s) Organ in Humans

11. Flehmen response – sniffing for phermones

12. Receiving a Signal

13. Reception 1 Ligand 1 Receptor Binding between signal molecule (ligand) & receptor (plasma membrane protein) is highly specific Plasma membrane

14. 1 Ligand Transduction 2 Relay molecules in a signal transduction pathway Reception 1 Receptor Plasma membrane Shape change in receptor is often the initial transduction of the signal…

15. Plasma membrane Receptor Ligand Relay molecules in a signal transduction pathway Activation of cellular response TransductionResponse 2 3 Reception 1 Signal transduction pathway- series of steps by which signal on cell’s surface is converted into specific cellular response

16. Hydrophilic hormones act via a receptor on the plasma membrane Typically rapid cellular response – can include regulation of gene expression Plasma membrane Receptor Ligand Relay molecules in a signal transduction pathway Activation of cellular response TransductionResponse 2 3 Reception 1

17. Hydrophobic hormones directly regulate genetic machinery of cell

18. Many signaling pathways regulate synthesis of proteins by turning genes on or off

19. Hydrophobic hormones directly regulate genetic machinery of cell Many signaling pathways regulate synthesis of enzymes (proteins) by turning genes on or off Final activated molecule can function as a transcription factor

20. What does a “transcription factor” do?

21. Two important hydrophilic ligand receptors: Receptor tyrosine kinases G-protein coupled receptors

22. PDGF bind to specific tyrosine kinase receptors, a large group of membrane receptors LigandLigand receptor tyrosine kinase proteins Tyrosines (amino acid) Both monomers bind a ligand activated dimer Dimerization leads to the phosphorylation of each tyrosine 6 ATP 6 ADP Relay proteins are activated by the phosphorylated tyrosines activated relay proteins Cellular response Cellular response

23. PDGF bind to specific tyrosine kinase receptors, a large group of membrane receptors 6 ATP 6 ADP

24. Relay proteins are activated by the phosphorylated tyrosines Cellular response Cellular response Activated receptor tyrosine kinase can activate many different cellular responses

25. G-protein coupled receptors Ligand binding site Region interacts with G-proteins Protein Structure?

26. GTP G protein coupled receptor GDP G protein Enzyme GDP = guanosine diphosphate GTP = guanosine trihosphate Ligand GTP GDP Bound receptor can bind G protein GTP then displaces GDP GTP bound G-protein is released and binds to separate membrane-bound enzyme Activated Enzyme Cellular response G-protein is released after it hydrolyzes phosphate group, returning to the initial state GDP P-

27. AMP phosphodiesterase caffiene

28. Brian Koblinka Robert Lefkowitz Nobel prize 2012: structure of a G- protein coupled receptor Why is this a big deal? Beta-2 adrenergic receptor (asthma, hypertension, heart failure)