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 ; 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. I II III IV selctivity Ca E Ca/Na~ 3000 Na D K A Na/Ca ~ 1000 Ca start
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
Ken (1991) PNAS

31. Mutant V1/2 (mV) Wt 1±5 V1 100±6 V2 69±7 V3 -5±2 V4 -22±3 V5 -7±7L1 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 Neuroscience 7, 761–771 (October 2006) | doi:10.1038/nrn1988

47. KCNRG : K (Potassium) / CN (Channel) / RG (Regulator)+ T1
S S S S S5 p S6
Ball
KCNRG (monomer)n ?
D.V. Ivanov et al./FEBS Letters 539 (2003)

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

50. KS Krishnan 1976

51. YD Ramu Baron Chanda Anurag Varshney Kavitha S Sanjeev Upadhyay
S Nagarajan
Hyder Usman
5um
Ken McCormack