1. Vesicular transport Dr. med. habil. Kőhidai László Assoc. Professor
Depertment of Genetics, Cell- and Immunoibiology
Semmelwesi University
2016. October 10.

3. Intracellular vesicular transport
Communication – intracellular;
- cell-environment
Membrane system
Uptake of substances and transport to the place of digestion (lysosomes) - endocytosis
Transport of proteins between ER-Golgi and to the surface membrane - exocitózis

4. Main pathways of vesicular transport
In the biosynthetic secretory pathway (red arrows), proteins are translocated from the ER to the plasma membrane or (via late endosomes) to lysosomes
In the endocytotic pathway (green arrows), molecules are ingested in vesicles derived from the plasma membrane and delivered to early endosomes and then (via late endosomes) to lysosomes
Retrieval (Blue arrows)
Many endocytosed molecules are retrieved from early endosomes and returned to the cell surface for reuse
Some molecules are retrieved from the late endosome and returned to the Gogi
Some are retrieved from the Golgi and returned to the ER

5. Figure 13-1 Molecular Biology of the Cell (© Garland Science 2008)

6. Intracellular vesicular transport
Bidirectional, transport between compartment is balanced
Continous recyclicling of membrane proteins

7. Pathway of biosynthetic-
and secretory processes
Endocytosis
Recycling

8. Transport vesicles
Membrane bounded vesicles filled with different cargos
Secretion
Lysosomal enzymes
Components of surface membrane and the ECM
Direction of transport is determined by the components of the membrane see: donor and target compartments

9. Figure 13-2 Molecular Biology of the Cell (© Garland Science 2008)

10. Figure 13-3 Molecular Biology of the Cell (© Garland Science 2008)

11. Molecular bases of vesicular transport
Biosynthetic-secretory and endocytotic pathways join 10 or more compartments
Direction of the transport and fusion are determined by molecular matching (receptor/ligand)

12. Coated vesicles Role of the coat:
Components of the membrane (e.g. receptors) are concentrated into patches
Removal of coated surfaces and formation of vesicles

13. Types of coated vesicles
Clathrin-coated vesicles
COPI-coated vesicles
COPII-coated vesicles
Each type of vesicle has its own transport

14. We can distinguish the TEM morphology of the three types of vesicles

15. Clathrin coated vesicles

16. Figure 13-7a, b Molecular Biology of the Cell (© Garland Science 2008)

17. Position of heavy and light chains in the wall
Clathrin-coat
Position of heavy and light chains in the wall

18. Comparison of clathrin composition
Light chain
Heavy chain

19. Clathrin

20. Protein-protein and protein-lipid associations
under clathrin coat

21. Clathrin binding proteins in Mammals

22. Releasing of clathrin-coated vesicles
Alberts et all. Molecular Biology of the cell

23. Receptor-mediated endocytosis
Role of dynamin in the process of vesicle release
Dynamin is a G-protein, it binds and cleaves GTP
Alberts et all. Molecular Biology of the cell

25. Receptor-mediated endocytosis
Alberts et all. Molecular Biology of the cell

26. Vesicular transport between rER and Golgi

27. Figure 13-24b Molecular Biology of the Cell (© Garland Science 2008)

28. rER-Golgi: Forward transport – COPII (1)

29. rER-Golgi: Forward transport – COPII (2)
Figure Molecular Biology of the Cell (© Garland Science 2008)

30. rER-Golgi: Forward transport – COPII (3)
Figure 13-13d Molecular Biology of the Cell (© Garland Science 2008)

31. COPII

32. Figure 13-24b Molecular Biology of the Cell (© Garland Science 2008)

33. Golgi- rER: Retrograde transport – COPI
Figure 13-24a Molecular Biology of the Cell (© Garland Science 2008)

34. COPI

35. Vesicular transport in the cytoplasm

36. Coating molecular complex of retromer
- Retrograde transport of proteins from endosomes to the TGN -
SNX1 - Sorting nexin-1
PX – phosphoinositide
binding domain
BAR – dimerization and
membrane binding
VPS =vacuolar protein
sorting
VPS26
VPS29
VPS35

37. Main steps of vesicle targeting
SNARE – soluble N-ethylmaleimide sensitive
factor attachment protein receptor
Figure Molecular Biology of the Cell (© Garland Science 2008)

38. Regeneration phase of targeting system
NSF – N-ethylmaleimide sensitive factor
Figure Molecular Biology of the Cell (© Garland Science 2008)

39. Main steps of vesicle fusion
Figure Molecular Biology of the Cell (© Garland Science 2008)

40. Molecular interactions in fusion
– Trans-SNARE -
Figure Molecular Biology of the Cell (© Garland Science 2008)

41. Homotypic fusion
Figure Molecular Biology of the Cell (© Garland Science 2008)

42. Figure 13-15 Molecular Biology of the Cell (© Garland Science 2008)

43. Subcellular distribution of SNARE proteins
syntaxin
VAMP
SNAP-25
egyéb
CCP – cl.-coated pit
CCV – cl-coated vesic.
DCV – dense core vesic.
IC – intermed. comp.
SNARE – soluble N-ethylmaleimide sensitive
factor attachment protein receptor

44. Figure 13-52 Molecular Biology of the Cell (© Garland Science 2008)

45. Figure 13-54 Molecular Biology of the Cell (© Garland Science 2008)

46. Endosomal sorting of ubiquitinated cargo proteins
Multivesicular bodies
ESCRT - endosomal sorting complex required for transport
Figure Molecular Biology of the Cell (© Garland Science 2008)

47. Chief cofactors of transport

48. Role of G-proteins in vesicular trasport (1)

49. Rab-cycle
docking
complex

50. Role of G-proteins in vesicular trasport (2)

51. Significance of phosphatidylinositol phosphates (1)

52. Significance of phosphatidylinositol phosphates (2)

53. Phylogeny of vesicular transport

54. Number of genes responsible for vesicular transport
Phylogenetical approaches
Number of genes

55. Evolution of SNARE-s
S. cerevisiae
H. sapiens

56. Exocytosis

57. Main steps of exocytosis
Figure 13-66a Molecular Biology of the Cell (© Garland Science 2008)

58. Figure 13-66b Molecular Biology of the Cell (© Garland Science 2008)

59. in cargo concentration
Membrane removal
in cargo concentration
Figure 13-65a Molecular Biology of the Cell (© Garland Science 2008)

60. Figure 13-72a Molecular Biology of the Cell (© Garland Science 2008)