Role of Repeat I in the fast inactivation kinetics of the CaV2.3 channel

Bernatchez, Gérald; Berrou, Laurent; Benakezouh, Z; Ducay, J; Parent, Lucie

doi:10.1016/s0005-2736(01)00373-x

Cited by 13 publications

(16 citation statements)

References 43 publications

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“…Functional Expression of Wild-type and Mutants Channels-Oocytes were obtained from female Xenopus laevis clawed frog (Nasco, Fort Atkinson, WI) as described previously (1,34,35). Briefly, stage VI oocytes free of follicular cells were injected with 46 nl of a solution containing 28 ng of cRNA coding for the wild-type or mutated Ca V ␣1 subunit.…”

Section: Methodsmentioning

confidence: 99%

“…Oocytes were first impaled in a modified Ringer solution (in mM): 96 NaOH; 2 KOH; 1. Electrophysiological Data Acquisition and Analysis-PClamp software, Clampex 6.02 and Clampfit 6.02 (Axon instruments, Foster City, CA) was used for on-line data acquisition and analysis as previously described (1,34,35). Unless stated otherwise, data were sampled at 10 kHz and low pass-filtered at 5 kHz using the amplifier built-in filter.…”

Section: Methodsmentioning

confidence: 99%

“…Inactivation kinetics were quantified using R300 values, that is the ratio of the whole cell current remaining at the end of a 300-ms pulse (34,35,38). As inactivation kinetics can vary with current density, comparisons between constructs and mutants were generally restricted to whole cell currents lower than Ϫ5 A as much as possible.…”

Section: Methodsmentioning

confidence: 99%

“…As seen, the signal was similar for the two aromatic mutations Y383F and Y383W confirming that the aromatic side-chain is a key structural requirement. Furthermore, positively charged residues were more tolerated than the negatively charged ones suggesting that electrostatic-based interactions are important for [ 35 (Fig. 4, C and D).…”

Section: A Three-dimensional Model Of the Aid Peptide From Ca V 23-mentioning

confidence: 99%

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The C-terminal Residues in the Alpha-interacting Domain (AID) Helix Anchor CaVβ Subunit Interaction and Modulation of CaV2.3 Channels

Berrou

Dodier

Raybaud

et al. 2005

Journal of Biological Chemistry

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The alpha-interacting domain (AID) in the I-II linker of high voltage-activated (HVA) Ca 2؉ channel ␣1 subunits binds with high affinity to Ca V ␤ auxiliary subunits. The recently solved crystal structures of the AIDCa V ␤ complex in Ca V 1.1/1.2 have revealed that this interaction occurs through a set of six mostly invariant residues Glu/Asp 6 (9). Ca V ␤ subunit modulation of LVA T-type (Ca V 3.1-3.3) channels has yet to be reported (10).Ca V ␤ subunits increase peak current density, in part by recruiting the Ca V ␣1 subunit to the plasma membrane (11)(12)(13)(14), by hyperpolarizing the voltage dependence of activation and inactivation, and by increasing the channel opening probability at the single channel level (4, 15). Ca V ␤ subunits increase inactivation kinetics in an isoform-specific manner with Ca V ␤3 Ͼ Ca V ␤1b Ͼ Ca V ␤1a Ͼ Ca V ␤4 Ͼ Ͼ Ca V ␤2a (4). The four known auxiliary Ca V ␤ subunits can potentially associate with any of the six Ca V ␣1 pore-forming subunits of HVA VDCC (Ca V 1.1-1.4, Ca V 2.1-2.3) via the alpha interaction domain (AID) located on the I-II linker of the Ca V ␣1 subunit. The AID motif is absent from LVA T-type (Ca V 3.1-3.3) VDCC for which Ca V ␤ subunit modulation has never been reported. About half of the residues of the AID helix (Gln 1 -Gln 2 -X 3 -Glu 4 -X 5 -X 6 -Leu 7 -X 8 -Gly 9 -Tyr 10 -X 11 -X 12 -Trp 13 -Ile 14 -X 15 -X 16 -X 17 -Glu 18 ) are strictly conserved (in bold) among the six Ca V ␣1 subunits but homology was found to be higher within members of the Ca V 1 and Ca V 2 families. Nonetheless, positions 8, 11, and 15 are occupied by residues that could vary even within the same Ca V family (Table I) (where X can be any residue) might not be the unique determinant of the Ca V ␣1-␤ interaction. In vitro binding experiments have revealed the presence of additional interaction sites of lower affinity on the cytoplasmic loops of Ca V 2.1 (16,17) and on the C-terminal of Ca V 2.3 (18) but the AID appears to be the primary high affinity site of interaction (14, 15).

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: A Three-dimensional Model Of the Aid Peptide From Ca V 23-mentioning

confidence: 99%

See 2 more Smart Citations

The C-terminal Residues in the Alpha-interacting Domain (AID) Helix Anchor CaVβ Subunit Interaction and Modulation of CaV2.3 Channels

Berrou

Dodier

Raybaud

et al. 2005

Journal of Biological Chemistry

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“…This is a nonsilent mutation creating a Gly to Arg mutation (G511R). The resulting Ca V 1.2 (XhoI) channel (which will be referred to herein as the Ca V 1.2 control channel) displayed inactivation and activation kinetics similar to the wild-type Ca V 1.2 (35,36). Constructs were verified by restriction mapping after religation of the mutated fragment into the SacI/XhoI sites of the wild-type Ca V 1.2.…”

Section: ϫ4mentioning

confidence: 99%

The Role of the GX9GX3G Motif in the Gating of High Voltage-activated Ca2+ Channels

Raybaud

Dodier

Bissonnette

et al. 2006

Journal of Biological Chemistry

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The putative hinge point revealed by the crystal structure of the MthK potassium channel is a glycine residue that is conserved in many ion channels. In high voltage-activated (HVA) Ca V channels, the mid-S6 glycine residue is only present in IS6 and IIS6, corresponding to G422 and G770 in Ca V 1.2. Two additional glycine residues are found in the distal portion of IS6 (Gly 432 and Gly 436 in Ca V 1.2) to form a triglycine motif unique to HVA Ca V channels. Lethal arrhythmias are associated with mutations of glycine residues in the human L-type Ca 2؉ channel. Hence, we undertook a mutational analysis to investigate the role of S6 glycine residues in channel gating. In Ca V 1.2, ␣-helix-breaking proline mutants (G422P and G432P) as well as the double G422A/G432A channel did not produce functional channels. The macroscopic inactivation kinetics were significantly decreased with Ca V 1.2 wild type > G770A > G422A Х G436A Ͼ Ͼ G432A (from the fastest to the slowest). Mutations at position Gly 432 produced mostly nonfunctional mutants. Macroscopic inactivation kinetics were markedly reduced by mutations of Gly 436 to Ala, Pro, Tyr, Glu, Arg, His, Lys, or Asp residues with stronger effects obtained with charged and polar residues. Mutations within the distal GX 3 G residues blunted Ca 2؉ -dependent inactivation kinetics and prevented the increased voltage-dependent inactivation kinetics brought by positively charged residues in the I-II linker. In Ca V 2.3, mutation of the distal glycine Gly 352 impacted significantly on the inactivation gating. Altogether, these data highlight the role of the GX 3 G motif in the voltage-dependent activation and inactivation gating of HVA Ca V channels with the distal glycine residue being mostly involved in the inactivation gating.Voltage-dependent calcium channels are membrane-bound proteins that form large aqueous pores for the selective diffusion of Ca 2ϩ ions across the plasma membrane (1, 2). Native Ca 2ϩ channels are composed of the pore-forming Ca V ␣1, the disulfur-linked dimer Ca V ␣2␦, the intracellular Ca V ␤ subunits (␤1-␤4), and in some cases the Ca V ␥ subunit (3). To date, molecular cloning has identified the primary structures for 10 distinct calcium channel Ca V ␣ 1 subunits (1, 4 -9) that are classified into three main subfamilies according to their gating properties (Ca V 1, Ca V 2, and Ca V 3). Whereas all voltage-gated Ca 2ϩ channel ␣1 subunits activate and inactivate in response to membrane depolarization, the high voltage-activated (HVA) 2 Ca V 1 and Ca V 2 ␣1 subunits operate at markedly more positive membrane potentials than low voltage-activated Ca V 3 channel ␣1 subunits.In the absence of a crystal structure for these proteins, details regarding the structural determinants of the channel inner pore as well as the molecular mechanism underlying the activation of Ca V ␣1 subunits remain sketchy. Structural studies have revealed that the architecture of the ion-selective pore is conserved in the homologous ␣ subunit of different K ϩ channels (10 -15) with the ...

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Molecular regions underlying the activation of low- and high-voltage activating calcium channels

Stevens

Wray

2005

Eur Biophys J

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We have studied two aspects of calcium channel activation. First, we investigated the molecular regions that are important in determining differences in activation between low- and high-voltage activated channels. For this, we made chimeras between the low-voltage activating Ca(V)3.1 channel and the high-voltage activating Ca(V)1.2 channel. Chimeras were expressed in oocytes, and calcium channel currents recorded by voltage clamp. For domain I, we found that the molecular region that is important in determining the voltage dependence of activation comprises the pore regions S5-P as well as P-S6, but surprisingly not the voltage sensor S1-S4 region, which might have been expected to play a major part. By contrast, the smaller, but still significant, modulating effects of domain II on activation properties were due to effects involving both S1-S4 and S5-S6 but not the I/II linker. Second, during channel activation we studied movement of the S4 segment in domain I of one of the chimeras, using cysteine-scanning mutagenesis. The reagent parachloromercuribenzensulfonate inhibited currents for mutants V263, A265, L266 and A268, but not for F269 and V271, and voltage dependence of inhibition for residue V263 indicated S4 movement, which occurred before channel opening. The data indicate movement outwards upon depolarisation so as to expose amino acids up to residue 268 in S4.

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Role of Repeat I in the fast inactivation kinetics of the CaV2.3 channel

Cited by 13 publications

References 43 publications

The C-terminal Residues in the Alpha-interacting Domain (AID) Helix Anchor CaVβ Subunit Interaction and Modulation of CaV2.3 Channels

The C-terminal Residues in the Alpha-interacting Domain (AID) Helix Anchor CaVβ Subunit Interaction and Modulation of CaV2.3 Channels

The Role of the GX9GX3G Motif in the Gating of High Voltage-activated Ca2+ Channels

Molecular regions underlying the activation of low- and high-voltage activating calcium channels

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