title: Molecular characterization and functional expression of the Apis mellifera voltage-dependent Ca2+ channels.
abstract: Voltage-gated Ca(2+) channels allow the influx of Ca(2+) ions from the extracellular space upon membrane depolarization and thus serve as a transducer between membrane potential and cellular events initiated by Ca(2+) transients. Most insects are predicted to possess three genes encoding Cavα, the main subunit of Ca(2+) channels, and several genes encoding the two auxiliary subunits, Cavβ and Cavα2δ; however very few of these genes have been cloned so far. Here, we cloned three full-length cDNAs encoding the three Cavα subunits (AmelCav1a, AmelCav2a and AmelCav3a), a cDNA encoding a novel variant of the Cavβ subunit (AmelCavβc), and three full-length cDNAs encoding three Cavα2δ subunits (AmelCavα2δ1 to 3) of the honeybee Apis mellifera. We identified several alternative or mutually exclusive exons in the sequence of the AmelCav2 and AmelCav3 genes. Moreover, we detected a stretch of glutamine residues in the C-terminus of the AmelCav1 subunit that is reminiscent of the motif found in the human Cav2.1 subunit of patients with Spinocerebellar Ataxia type 6. All these subunits contain structural domains that have been identified as functionally important in their mammalian homologues. For the first time, we could express three insect Cavα subunits in Xenopus oocytes and we show that AmelCav1a, 2a and 3a form Ca(2+) channels with distinctive properties. Notably, the co-expression of AmelCav1a or AmelCav2a with AmelCavβc and AmCavα2δ1 produces High Voltage-Activated Ca(2+) channels. On the other hand, expression of AmelCav3a alone leads to Low Voltage-Activated Ca(2+) channels.
authors.affiliation: Institut des Biomolécules Max Mousseron (IBMM), CNRS UMR 5247, Place Eugène Bataillon, 34095 Montpellier cedex 5, France; Centre de Recherche de Biochimie Macromoléculaire (CRBM), CNRS UMR 5237, 1919 Route de Mende, 34293 Montpellier cedex 5, France; Université de Montpellier, Place Eugène Bataillon, 34095 Montpellier cedex 5, France. Electronic address: thierry.cens@crbm.cnrs.fr.
authors.forename: Thierry
authors.initials: T
authors.lastname: Cens
authors.affiliation: Institut des Biomolécules Max Mousseron (IBMM), CNRS UMR 5247, Place Eugène Bataillon, 34095 Montpellier cedex 5, France; Centre de Recherche de Biochimie Macromoléculaire (CRBM), CNRS UMR 5237, 1919 Route de Mende, 34293 Montpellier cedex 5, France; Université de Montpellier, Place Eugène Bataillon, 34095 Montpellier cedex 5, France. Electronic address: matthieu.rousset@crbm.cnrs.fr.
authors.forename: Matthieu
authors.initials: M
authors.lastname: Rousset
authors.affiliation: INRA UR 406 Abeilles et Environnement, 228 Route de l'aérodrome, Domaine Saint Paul, Site Agroparc, CS40509, 84914 Avignon cedex 9, France. Electronic address: claude.collet@avignon.inra.fr.
authors.forename: Claude
authors.initials: C
authors.lastname: Collet
authors.affiliation: INRA UR 406 Abeilles et Environnement, 228 Route de l'aérodrome, Domaine Saint Paul, Site Agroparc, CS40509, 84914 Avignon cedex 9, France. Electronic address: mercedes.charreton@avignon.inra.fr.
authors.forename: Mercedes
authors.initials: M
authors.lastname: Charreton
authors.affiliation: Laboratoire Evolution Génome et Spéciation (LEGS), CNRS UPR 9034, Avenue de la Terrasse, Bâtiment 13, 91198 Gif sur Yvette, France. Electronic address: lionel.garnery@legs.cnrs-gif.fr.
authors.forename: Lionel
authors.initials: L
authors.lastname: Garnery
authors.affiliation: INRA UR 406 Abeilles et Environnement, 228 Route de l'aérodrome, Domaine Saint Paul, Site Agroparc, CS40509, 84914 Avignon cedex 9, France. Electronic address: yves.leconte@avignon.inra.fr.
authors.forename: Yves
authors.initials: Y
authors.lastname: Le Conte
authors.affiliation: Centre de recherche, Institut universitaire en santé mentale de Québec, 2601 Chemin de la Canardière, Québec Québec G1J 2G3, Canada. Electronic address: mohamed.chahine@phc.ulaval.ca.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Chahine
authors.affiliation: Laboratoire Evolution Génome et Spéciation (LEGS), CNRS UPR 9034, Avenue de la Terrasse, Bâtiment 13, 91198 Gif sur Yvette, France. Electronic address: jean-christophe.sandoz@legs.cnrs-gif.fr.
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Sandoz
authors.affiliation: Institut des Biomolécules Max Mousseron (IBMM), CNRS UMR 5247, Place Eugène Bataillon, 34095 Montpellier cedex 5, France; Centre de Recherche de Biochimie Macromoléculaire (CRBM), CNRS UMR 5237, 1919 Route de Mende, 34293 Montpellier cedex 5, France; Université de Montpellier, Place Eugène Bataillon, 34095 Montpellier cedex 5, France. Electronic address: pierre.charent@crbm.cnrs.fr.
authors.forename: Pierre
authors.initials: P
authors.lastname: Charnet
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001516:Bees / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020864:Calcium Channels, N-Type / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D005091:Exons; D019476:Insect Proteins / Q000378:metabolism; D008564:Membrane Potentials; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D014981:Xenopus
chemical_list: D002118:Calcium; D015220:Calcium Channels; D020864:Calcium Channels, N-Type; D019476:Insect Proteins
keywords: Ca(2+) channels; Cloning; Electrophysiology; Honeybee; Xenopus oocytes