Voltage-Gated K + Channels

1. Voltage-Gated K+ Channels MK Mathew NCBS, TIFR UAS – GKVK Campus Bangalore IBRO Course in Neuroscience Center for Cognitive Neuroscience & Semantics, University of Latvia Riga, Latvia August 21-August 29, 2013

4. PROPERTIES OF VOLTAGE-GATED ION CHANNELS • Voltage sensitive • Requires voltage-sensing apparatus • Requires transduction machinery • High Throughput: 108 ions/second • Protein supports an aqueous column traversing the membrane • Discriminates between Na+ and K+ • Requires a selectivity filter

6. 1982 Noda … Numa Nature AChR a-subunit cloned from peptide information • 1983 Noda … Numa Nature All AChR subunits cloned • 1984 Noda … Numa Nature Na channel a-subunit cloned • 1987 Stuhmer .. Numa Eur J Biophys Xenopus expression Na channel • 1989 Stuhmer Conti .. Numa Nature S4 mutations in Na channel

7. Sodium Channel

8. 1982 Noda … Numa Nature AChR a-subunit cloned from peptide information • 1983 Noda … Numa Nature All AChR subunits cloned • 1984 Noda … Numa Nature Na channel a-subunit cloned • 1987 Stuhmer .. Numa Eur J Biophys Xenopus expression Na channel • 1989 Stuhmer Conti .. Numa Nature S4 mutations in Na channel • 1987 Kamb Iverson Tanouye Cell • 1987 Papazian … Jan Science Shaker Cloning • !988 Pongs … Ferrus EMBO J

10. Xenopus oocytes Two Electrode Voltage clamp

11. ELECTROPHYSIOLOGICAL PROPERTIES OF HUMAN K+ CHANNELS

13. hKv1.4

15. KcsA Doyle et al., Science 1998; 280: 69

16. Doyle et al., Science 1998; 280: 69 Jiang et al., Nature 2002 417; 523

17. Gary Yellen

18. KcsA Doyle et al., Science 1998; 280: 69

19. Zhou .. MacKinnon (01) Nature

20. Varma & Rempe (2007) Biophys J 93:1093–1099

21. Zhou .. MacKinnon (01) Nature

23. Payandeh .. Catterall (2011) Nature

24. RajGanesh et al (2000) Proteins

25. KcsA Doyle et al., Science 1998; 280: 69

27. Kv 1.2 Crystal Structure MacKinnon ,2005

28. … Catterall (2006) PNAS

29. Pathak .. Isacoff (2007) Neuron

30. Sequence Alignment of The S4-S5 Region S4 S5 Ken (1991) PNAS

31. L1 L2 L3 L4 L5 Mutant V1/2 (mV) Wt 1±5 V1 100±6 V2 69±7 V3 -5±2 V4 -22±3 V5 -7±7 V2A3 32±5 V1/2 Val/Ala mutations in Shaker Phenylalanine mutations in hKv 1.4 McCormack et al., (1991) Judge et al., (2002) McCormack et al (91) PNAS

32. Bezanilla (2000) Physiol Rev 80, 555 - 592

33. Gating charge Sensor Movement Po Schoppa Sigworth (98) JGP

35. Kv 1.2 Crystal Structure MacKinnon ,2005

36. L312M-L326V DV1/2 = 0 mV V406L–L312M DV1/2 = -42 mV A305L-L312M DV1/2 = +18 mV Sanjeev

37. Sanjeev, Nagarajan J Physiol

38. OPEN STATE Sanjeev, Nagarajan

39. CLOSED STATE

40. CLOSED OPEN Sanjeev, Nagarajan J Physiol

41. Gating charge Po Ledwell Aldrich (99) JGP

42. Gating charge Po Ledwell Aldrich (99) JGP

43. ACTIVATED STATE

44. CLOSED ACTIVATED OPEN

45. Sanjeev, Nagarajan J Physiol

46. Kaczmarek Nature Reviews Neuroscience7, 761–771 (October 2006) | doi:10.1038/nrn1988

47. + + + + S1 S2 S3 S4 S5 p S6 T1 Ball KCNRG (monomer)n ? T1 KCNRG : K (Potassium) / CN (Channel) / RG (Regulator) D.V. Ivanov et al./FEBS Letters 539 (2003) 156-160

48. 5um Surface Expression Analysis KCNRG reduces Surface targeting of hKv 1.4 Hyder (2010)

50. KS Krishnan 1976