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Voltage-Gated K + Channels MK Mathew NCBS, TIFR UAS – GKVK Campus Bangalore IBRO Course in Neuroscience Center for Cognitive Neuroscience & Semantics,

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Presentation on theme: "Voltage-Gated K + Channels MK Mathew NCBS, TIFR UAS – GKVK Campus Bangalore IBRO Course in Neuroscience Center for Cognitive Neuroscience & Semantics,"— Presentation transcript:

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

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4 PROPERTIES OF VOLTAGE-GATED ION CHANNELS Voltage sensitive Requires voltage-sensing apparatus Requires transduction machinery High Throughput: 10 8 ions/second Protein supports an aqueous column traversing the membrane Discriminates between Na + and K + Requires a selectivity filter

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6 1982Noda … Numa NatureAChR a-subunit cloned from peptide information 1983Noda … Numa NatureAll AChR subunits cloned 1984Noda … Numa NatureNa channel a-subunit cloned 1987Stuhmer.. Numa Eur J Biophys Xenopus expression Na channel 1989Stuhmer Conti.. Numa NatureS4 mutations in Na channel

7 Sodium Channel

8 1982Noda … Numa NatureAChR a-subunit cloned from peptide information 1983Noda … Numa NatureAll AChR subunits cloned 1984Noda … Numa NatureNa channel a-subunit cloned 1987Stuhmer.. Numa Eur J Biophys Xenopus expression Na channel 1989Stuhmer Conti.. Numa NatureS4 mutations in Na channel 1987Kamb Iverson Tanouye Cell 1987Papazian … JanScienceShaker Cloning !988Pongs … FerrusEMBO J

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10 Xenopus oocytes Two Electrode Voltage clamp

11 ELECTROPHYSIOLOGICAL PROPERTIES OF HUMAN K + CHANNELS

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13 hKv1.4

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

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

17 Gary Yellen

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

19 Zhou.. MacKinnon (01) Nature

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

21 Zhou.. MacKinnon (01) Nature

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23 Payandeh.. Catterall (2011) Nature

24 IIIIIIIVselctivity CaEEEECa/Na~ 3000 NaDEKANa/Ca ~ 1000 Ca startEEKENa/Ca ~ 100 RajGanesh et al (2000) Proteins

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

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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 Phenylalanine mutations in hKv 1.4 Val/Ala mutations in Shaker McCormack et al., (1991) Judge et al., (2002) MutantV 1/2 (mV) Wt 1±5 V1100±6 V269±7 V3-5±2 V4-22±3 V5-7±7 V2A332±5 McCormack et al (91) PNAS V 1/2 L1L2L3L4L5

32 Bezanilla (2000) Physiol Rev 80,

33 Schoppa Sigworth (98) JGP Gating charge Sensor Movement PoPo

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35 Kv 1.2 Crystal Structure MacKinnon,2005

36 L312M-L326V  V 1/2 = 0 mV V406L–L312M  V 1/2 = -42 mV A305L-L312M  V 1/2 = +18 mV Sanjeev

37 Sanjeev, Nagarajan J Physiol

38 OPEN STATE Sanjeev, Nagarajan

39 CLOSED STATE

40 CLOSEDOPEN Sanjeev, Nagarajan J Physiol

41 Ledwell Aldrich (99) JGP Gating charge PoPo

42 Ledwell Aldrich (99) JGP Gating charge PoPo

43 ACTIVATED STATE

44 CLOSEDACTIVATEDOPEN

45 Sanjeev, Nagarajan J Physiol

46 Kaczmarek Nature Reviews Neuroscience 7, 761–771 (October 2006) | doi: /nrn1988

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

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

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50 KS Krishnan 1976

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


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