1. Last Class: 1. Posttranscription regulation
2. Translation regulation
3. Cell membrane, phospholipids, cholesterol
4. Membrane protein, mobility, FRAP, FLIP

2. Carbohydrate layer (Glycocalyx) on the cell surface
Protecting the cell surface from mechanical and chemical damage
Lymphocyte stained with ruthenium red

3. Diagram of glycocalyx

4. Summary membrane proteins and their anchoring models
Methods to study membrane proteins, detergents
diffusion, distribution, methods to study protein motion and distribution
glycocalyx, proteoglycan

5. Membrane Transport of Small Molecules and the Electrical Properties of Membranes

7. Permeability of plasma membrane
General principles I

8. Permeability of plasma membrane General principles II
Permeability coefficient (cm/sec)

9. Membrane Transport Proteins Carrier Protein and Channel Protein

10. Transportation Models Passive and Active Transport
Electrochemical and concentration gradient, membrane potential
Carrier proteins: passive and active
Channels: always passive

11. Electrochemical Gradient
Is the combinatory effect of concentration gradient and membrane potentials

12. Ionophores can serve as channels and carriers for ions
Example: A23187, calcium permeabilizing agent

13. Carrier Proteins and Active Membrane Transportation

14. Conformational change of a carrier protein Mediates passive transport
Change is spontaneous and random, so dependent on concentration

15. Kinetics of simple and carrier-mediated diffusions

16. 3 ways of driving active transportation utilizing passive carriers
Coupled carriers
ATP-driven pumps
Light-driven pumps

17. 3 types of carrier-mediated transport
Coupled carriers

18. Coupled transportation of glucose and Na+
Cooperative binding of Na+ and glucose to the carrier.
Outer surface, Na+ high concentration induces the high affinity of glucose to carrier

19. Transcellular transport
Tight junction separates apical and basal/lateral spaces
Apical: glucose and Na+ coupling; basal/lateral: glucose is passive, Na+ maintained by ATP-driven pump

20. P-type transport ATPase (dependent on phosphorylation)
Na+-K+ Pump, ATPase
P-type transport ATPase (dependent on phosphorylation)

21. Cycles of Na+-K+ Pump

22. Calcium Pump
ATP binding and hydrolysis can push calcium inside by bring N and P domain together

23. 1. selectivity, 2. Gated (close and open)
A typical Ion Channel
1. selectivity, 2. Gated (close and open)

24. The gating of Ion Channels

25. The Structure of bacterial K+ channel
Selectivity 10,000 fold over Na, although K nm, Na nm

26. The Selectivity of bacterial K+ channel
Carbonyl oxygens at selective filter

27. Gating Model of K+ channel
Selectivity filter is fixed, the vestibule open and close like a diaphragm

28. Summary Membrane transportation, carrier protein, channel protein
Active transportation, passive transportation
Carrier Proteins, coupled carriers, ATPases, Na+-K+ Pump
Gating mechanisms of Ion Channels, K+ channel selectivity

29. Intracellular Compartments and Protein Sorting

30. The major intracellular compartments of an animal cell

31. An electron micrograph of part of a live cell seen in cross section

32. Hypothetical schemes for the evolutionary origins of organelles

33. Topological relationships between compartments of the secretory and endocytic pathways in a eucaryotic cell

34. A schematic roadmap of protein traffic Red: gated transport
Blue: transmembrane transport
Green: vesicular transport

35. Vesicle budding and fusion during vesicular transport

36. Two ways in which a sorting signal can be built into a protein
Signal sequence
Signal patch

38. The transport of molecules between the nucleus and the cytosol

40. The nuclear envelope

41. The arrangement of nuclear pore complexes in the nuclear envelope

42. Possible paths for free diffusion through the nuclear pore complex

43. The function of a nuclear localization signal
Nuclear localization signal: NLS
Nuclear export signal: NES

44. Nuclear import receptors

45. The compartmentalization of Ran-GDP and Ran-GTP
Ran-GAP: cytosol->Ran-GDP
Ran-GEF: nucleus->Ran-GTP

46. A model for how GTP hydrolysis by Ran provides directionality for nuclear transport

47. A model for how Ran-GTP binding might cause nuclear import receptors to release their cargo

48. The control of nuclear import during T-cell activation

49. The endoplasmic reticulum

51. Fluorescent micrographs of the endoplasmic reticulum

52. The rough ER

53. Free and membrane-bound ribosomes

54. The Isolation of purified rough and smooth microsomes from the ER

55. The signal hypothesis

56. The signal-recognition particle (SRP)

57. How ER signal sequences and SRP direct ribosomes to the ER membrane

58. Evidence for a continuous aqueous pore joining the ER lumen and the interior of the ribosome

59. Three ways in which protein translocation can be driven through structurally similar translocators

60. A model for how a soluble protein is translocated across the ER membrane

61. How a single-pass transmembrane protein with a cleaved ER signal sequence is integrated into the ER membrane

62. Integration of a single-pass membrane protein with an internal signal sequence into the ER membrane

63. Integration of a double-pass membrane protein with an internal signal sequence into the ER membrane

64. The insertion of the multipass membrane protein rhodopsin into the ER membrane

65. The asparagine-linked (N-linked) precursor oligosaccharide that is added to most proteins in the rough ER membrane

66. Protein glycosylation in the rough ER

67. The role of N-linked glycosylation in ER protein folding
Calnexin: membrane-bound chaperone protein
Calreticulin: soluble chaperone protein

68. The export and degradation of misfolded ER proteins

69. The unfolded protein response in yeast

70. The attachment of a GPI anchor to a protein in the ER

71. The synthesis of phosphatidylcholine

72. The role of phospholipid translocation in lipid bilayer synthesis

73. Phospholipid exchange proteins

74. Summary Nucleus translocation, NLS, NES, nuclear pore complex, Ran-GTP
Endoplasmic reticulum, rough ER, smooth ER,
SRP, soluble and membrane proteins in ER,
Glycosylation in ER, folding,
Membrane lipid bilayer assembly