1. Transcription Translation Molecular Structure of Ion Channels

2. Specialized proteins embedded within the bilayer: 1. Receptors 2. Cell Adhesion Molecules 3. Ion Channels -control the movement of molecules in and out of the cell.

3. Proteins: chains of amino acids. Amino Acids: -there are only 20 different amino acids (AA). C NH 3 (amino) COOH (acid) Side Chain -each has a central carbon atom. -each has an amino group -each has an acid group -they differ only in their side chains.

4. COO - C + NH 3 H CH 2 NH 3 + Lysine: COO - C + NH 3 H CH 2 COO - Glutamic Acid:

5. -fold because of differences in charge along the protein. AA -type of protein is determined by the sequence of AAs.

7. Protein Synthesis Nucleic Acids: -control which proteins to make. DNA: -found in the nucleus (chromosomes). -contains the instructions for protein synthesis. -messenger RNA (mRNA).

8. Nucleus Soma DNA mRNA Transcription Translation Protein

9. IntronsExons Introns: non coding regions of DNA Exons: coding regions of DNA mRNA mRNA (final) DNA Transcription “Splicing”

10. Studying Ion Channel Structure How to make a sodium ion channel: 1. Purify the protein from a rich source. Electric eel

11. 2. Identify short sequences of amino acids within protein. 3. Make a single strand of DNA that matches the sequence. (Oligonucleotide) -attach a fluorescent probe.

12. 4. Take samples of mRNA from a source containing sodium channel mRNA.

13. 5. Make a cDNA library from the mRNAs. cDNA: -complementary DNA (single strand). mRNA Reverse Transcriptase cDNA -the cDNA from the sodium channel protein mRNA will contain a region that exactly matches (complements) the the oligonucleotide.

14. 6. Use the oligonucleotide to identify the correct cDNA.

15. 7. From the isolated cDNA, the amino acid sequence can be determined. Sodium Channel: 2000 amino acids long What is the structure of the channel? So what!

16. -some subunits are hydrophobic (in the membrane). -connected by hydrophilic loops (outside the membrane).

17. Hydrophobicity Plot: -some amino acids are hydrophobic and are therefore found within the membrane.

19. The Sodium Channel

20. Mutant Flies

21. The Shaker Mutation

22. Alternative Splicing of Shaker Locus

23. Shaker Splice Variants

24. Heterologous Expression

25. Site-Directed Mutagenesis

26. Membrane Ion Currents

27. Conductance Leads to Voltage Change

28. NA + /K + Conductance Ratio

29. Summed Membrane Currents

30. NA + /K + G, I, V & E

31. Voltage Clamp

32. Depolarization and Currents

33. Nonlinear Voltage-Dependent Currents

34. Na+ Ions Produce Inward Current

35. NA + /K + Channel Pharmacology

36. Voltage-dependent Ion Channels

37. Structure of K + Channel / S4 Region

38. Gating Current

39. Channel Activation and Inactivation

40. Pronase Inactivation

41. Ball and Chain Model

42. Mutated Shaker and Restoration

43. Dynamics of Action Potential http://www.blackwellscience.com/matthews/channel.html

44. Diversity of Ion Channels

45. Channels That Carry Inward Currents

46. Calcium Currents

47. Dihydropyridines

48. Calcium Channel Subunits

49. Channels That Carry Outward Currents

50. Diversity of K + Currents

51. Transient K + A-Current

52. Intercellular Communication

53. Gap Junctions and Neurosecretion

54. Three Modes of Cellular Communication: 1.Cell-to-Cell through gap junctions 2. Chemical release through secretion 3. Direct physical contact

55. Gap Junctions

56. Monomer connexins make a connexon

57. Detecting Electrical-Coupling

58. Single Channel Records of Gap Junctions