1. Last Class 1. ECM components: glycosaminoglycans (GAGs) and fibrous proteins a. GAGs: Hyaluronan; Chondroitin sulfate and dermatan sulfate; Heparan sulfate; Keratan sulfate b. Fibrous proteins: collagen, elastin, fibronectin, laminin 2. basal laminae, neuromuscular junction 3. Cell-ECM interaction, ECM degration 4. ECM receptor, integrins

2. Cell Junctions, Cell- Cell Adhesions

3. CrossSection View of Intestine Wall

4. * * * * * * * *

5. Tight Junctions Claudins, Occludins ZO Proteins

6. Tight Junctions as barriers to solute diffusion Electron-dense tracer is added in the apical (B) and basal sides of the cells (C).

7. Tight Junctions Structures Freeze-fracture EM

8. Models for Tight Junctions Claudin and occludin

9. Anchoring Junctions Connecting cytoskeletons

10. Two Classes of anchoring junctions

11. Anchoring junctions 1.Adherens junctions (cell-cell) 2.Desmosomes (cell-cell) 3.Focal adhesions and hemidesmosomes (cell-ECM)

13. Adherens Junctions

15. Folding of an epithelial sheet to form an epithelial tube

16. Desmosomes

18. Focal Adhesion

19. hemiDesmosomes and desmosomes

20. Gap Junctions Size of molecules allowed to pass

21. Gap Junctions

22. Gap Junctions in EM

23. Regulation of Gap Junctions Rabbit retina and dopamine treatment Switch between rod and cone photoreceptors Lucifer yellow injection

24. Gap Junctions Functions 1.Rapid communication between neighboring cells, e.g. cardiomyocytes need synchronized actions 2. Communication beyond nerve system, e.g. hepatocytes beyond sympathetic nerves need to be informed to produce glucose from glycogen 3. Embryogenesis, form specific tissue with coupled group of cells

25. Summary of cell junctions

27. Cell-Cell Adhesions

28. Cell to Tissue mechanism A Simple Model

29. Cell to Tissue mechanism A More Complex Model Cell adhesion molecules (CAM)

31. Cell-cell Adhesion cadherins

32. Cell-cell Adhesion Regulation of cadherins

33. The distribution of E-cadherin (ectoderm) and N-cadherin (neural tube) in Chick embryo

34. Three mechanisms of cell-cell adhesions

35. Cadherin-dependent Cell Sorting

36. Cadherins are linked to actin filaments

37. Adherens Junction Formation movie movie

38. Selectin-mediated cell-cell adhesion (blood cell rolling) E-selectin, L-selectin, P-selectin

39. White Blood Cell Rolling and Adhesion Movie Movie

40. Neural cell adhesion molecule (N-CAM), intercellular adhesion molecule (ICAM) Calcium-independent Immunoglobulin (Ig) superfamily

41. Summary Diagram non-junctional adhesion proceeds junctional adhesion

42. Summary 1. Junctions: Occluding Junctions, Anchoring Junctions, Communicating Junctions 2. Occluding Junctions: Tight Junction 3. Anchoring Junctions: adherens Junction 4. Communicating Junctions: Gap Junction 5. Cell-Cell Junction: adherens junction, cadherins

43. Overview of the Cell Membrane structure and components, membrane proteins, carrier proteins, channel proteins Signaling transduction, ligand-receptor interactions, ion-channels, GPCRs, RTKs, molecular switches (kinase, GTPases), molecular complex formation and signaling integration, signaling desensitization, GPCR, GPCR signaling: cAMP, Calcium (CaM Kinase as memory molecule) RTK, RTK signaling: Ras, PI3K (PLC, Akt, Rac) Protease mediated signaling: NF-kB Cytoskeleton: microtubules, actin, intermediate filament Regulation of microtubules and actin Molecular motors: myosin (Sliding Acto-Myosin filaments ), kinesin Cell migration and its relationship with actin filaments Extracellular matrix: GAG, fibrous proteins (collagen, elastin, fibronectin, laminin) Basal laminae, cell-ECM interaction, integrins, cell-cell adhesion (tight junction, adherens junction, gap junction), cadherins