Amino acid substitutions in the pore affect the anomalous mole fraction effect of CaV1.2 channels

  • Authors:
    • Zhe Li
    • He Huang
    • Bo Yang
    • Hong Jiang
    • Guo-Feng Gao
    • Blaise Z. Peterson
    • Cong-Xin Huang
  • View Affiliations

  • Published online on: November 30, 2012     https://doi.org/10.3892/mmr.2012.1210
  • Pages: 571-576
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Abstract

The anomalous mole fraction effect (AMFE) is an important indicator of ion-ion interactions in the pore of voltage-gated Ca2+ channels (VGCCs). The residues at position 1144 that differ in several classes of VGCCs are important to the permeation of the pore. Phe-1144 (F, CaV1) was substituted with glycine (G, CaV2) and lysine (K, CaV3) and the effects of mutation on the voltage and concentration dependency of AMFE were observed. Whole-cell currents were recorded in external solutions with Ca2+ and Ba2+ at the indicated ratios with a total divalent cation concentration of 2, 10 or 20 mM, at holding potentials from -80 to -20 mV. Results showed the ratio of Ba2+ to Ca2+ currents determined at 2 mM to be different from that determined under higher concentrations for wild-type channels but this ratio was not different when tail currents were evoked at different potentials. AMFE was greatest at relatively positive potentials (-20 mV) and when the total divalent cation concentrations were kept low (2 mM). AMFE was attenuated for F/G while it was accentuated for F/K compared with wild-type, respectively. The results demonstrated that glycine and lysine substitutions of Phe-1144 affect AMFE through different mechanisms. Additionally, residues at position 1144 were shown to be major determinates of channel permeation of several classes of VGCCs.
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February 2013
Volume 7 Issue 2

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Spandidos Publications style
Li Z, Huang H, Yang B, Jiang H, Gao G, Peterson BZ and Huang C: Amino acid substitutions in the pore affect the anomalous mole fraction effect of CaV1.2 channels. Mol Med Rep 7: 571-576, 2013.
APA
Li, Z., Huang, H., Yang, B., Jiang, H., Gao, G., Peterson, B.Z., & Huang, C. (2013). Amino acid substitutions in the pore affect the anomalous mole fraction effect of CaV1.2 channels. Molecular Medicine Reports, 7, 571-576. https://doi.org/10.3892/mmr.2012.1210
MLA
Li, Z., Huang, H., Yang, B., Jiang, H., Gao, G., Peterson, B. Z., Huang, C."Amino acid substitutions in the pore affect the anomalous mole fraction effect of CaV1.2 channels". Molecular Medicine Reports 7.2 (2013): 571-576.
Chicago
Li, Z., Huang, H., Yang, B., Jiang, H., Gao, G., Peterson, B. Z., Huang, C."Amino acid substitutions in the pore affect the anomalous mole fraction effect of CaV1.2 channels". Molecular Medicine Reports 7, no. 2 (2013): 571-576. https://doi.org/10.3892/mmr.2012.1210