1. Cytoskeleton II
Chapter 16

2. Tubulin heterodimer is the microtubule subunit

3. Microtubule structure

5. Growing and shrinking microtubules

6. Growing and shrinking microtubules

7. Structure of actin

8. Actin binds to many different proteins

9. Intermediate filaments

10. Model of intermediate filament structure

11. Model of intermediate filaments

12. Intermediate filaments can withstand high levels of deforming force

13. Keratin filaments in an epithelial cell

14. Blistering of the skin caused by a mutant keratin gene
Normal skin

15. Blistering of the skin caused by a mutant keratin gene
Skin with
mutated
keratin gene

16. Blistering of the skin caused by a mutant keratin gene
Cells rupture
between the
nucleus and
the hemi-
desmosomes

17. Polymerization of tubulin is nucleated by the γ-tubulin ring

18. Electron micrograph of purified γ-tubulin complexes

19. Single microtubules nucleated from the γ-tubulin ring

20. The centrosome is the major microtubule organizing center of animal cells and contain γ-tubulin ring complexes

22. Centriole surrounded by centrosome matrix

23. figure 09-08a.jpg

24. figure 09-08a.jpg

25. figure jpg
Figure 9.9
Figure 9.9
spindle

27. figure 09-08b.jpg

28. Leading edge of cell nucleates actin filaments
all actin filaments
Newly formed
actin filaments

29. Model for actin filament nucleation by ARP complex

30. ARP complex nucleates more efficiently when bound to preexisting actin filament

31. Electron micrograph of branched actin filaments

32. Thymosin inhibition

33. Profilin recruitment

35. Stathmin sequesters free tubulin

36. Monomer concentration and capping protein determine growth or shrinkage rate

37. Stabilization and destabilization of microtubules

38. Capping proteins direct microtubules to specific locations in the cell