Negatively charged residues in the first extracellular loop of the L-type CaV1.2 channel anchor the interaction with the CaVα2δ1 auxiliary subunit

التفاصيل البيبلوغرافية
العنوان: Negatively charged residues in the first extracellular loop of the L-type CaV1.2 channel anchor the interaction with the CaVα2δ1 auxiliary subunit
المؤلفون: Benoîte Bourdin, Marie-Philippe Tétreault, Rémy Sauvé, Lucie Parent, Julie Briot
المصدر: Journal of Biological Chemistry. 292:17236-17249
بيانات النشر: Elsevier BV, 2017.
سنة النشر: 2017
مصطلحات موضوعية: 0301 basic medicine, biology, Molecular model, Chemistry, Protein subunit, Calcium channel, Cell Biology, Gating, Biochemistry, Cav1.2, Protein–protein interaction, 03 medical and health sciences, Electrophysiology, 030104 developmental biology, 0302 clinical medicine, Extracellular, Biophysics, biology.protein, Molecular Biology, 030217 neurology & neurosurgery
الوصف: Voltage-gated L-type CaV1.2 channels in cardiomyocytes exist as heteromeric complexes. Co-expression of CaVα2δ1 with CaVβ/CaVα1 proteins reconstitutes the functional properties of native L-type currents, but the interacting domains at the CaV1.2/CaVα2δ1 interface are unknown. Here, a homology-based model of CaV1.2 identified protein interfaces between the extracellular domain of CaVα2δ1 and the extracellular loops of the CaVα1 protein in repeats I (IS1S2 and IS5S6), II (IIS5S6), and III (IIIS5S6). Insertion of a 9-residue hemagglutinin epitope in IS1S2, but not in IS5S6 or in IIS5S6, prevented the co-immunoprecipitation of CaV1.2 with CaVα2δ1. IS1S2 contains a cluster of three conserved negatively charged residues Glu-179, Asp-180, and Asp-181 that could contribute to non-bonded interactions with CaVα2δ1. Substitutions of CaV1.2 Asp-181 impaired the co-immunoprecipitation of CaVβ/CaV1.2 with CaVα2δ1 and the CaVα2δ1-dependent shift in voltage-dependent activation gating. In contrast, single substitutions in CaV1.2 in neighboring positions in the same loop (179, 180, and 182-184) did not significantly alter the functional up-regulation of CaV1.2 whole-cell currents. However, a negatively charged residue at position 180 was necessary to convey the CaVα2δ1-mediated shift in the activation gating. We also found a more modest contribution from the positively charged Arg-1119 in the extracellular pore region in repeat III of CaV1.2. We conclude that CaV1.2 Asp-181 anchors the physical interaction that facilitates the CaVα2δ1-mediated functional modulation of CaV1.2 currents. By stabilizing the first extracellular loop of CaV1.2, CaVα2δ1 may up-regulate currents by promoting conformations of the voltage sensor that are associated with the channel's open state.
تدمد: 0021-9258
الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_________::0bfc5b3b07ebbe340082d2c85c51bb62Test
https://doi.org/10.1074/jbc.m117.806893Test
حقوق: OPEN
رقم الانضمام: edsair.doi...........0bfc5b3b07ebbe340082d2c85c51bb62
قاعدة البيانات: OpenAIRE