Institut des Biomolécules Max Mousseron (IBMM), UMR 5247, CNRS ENSCM, Université de Montpellier, bât. CRBM, 1919 Route de Mende, 34293 Montpellier cedex 5, France.
INRA, UR 406 Abeilles et Environnement, 228 Route de l'aérodrome, Domaine Saint Paul, Site Agroparc, CS40509, 84914 Avignon cedex 9, France.
Sci Rep. 2017 Feb 1;7:41782. doi: 10.1038/srep41782.
Voltage-gated Ca channels are key transducers of cellular excitability and participate in several crucial physiological responses. In vertebrates, 10 Ca channel genes, grouped in 3 families (Ca1, Ca2 and Ca3), have been described and characterized. Insects possess only one member of each family. These genes have been isolated in a limited number of species and very few have been characterized although, in addition to their crucial role, they may represent a collateral target for neurotoxic insecticides. We have isolated the 3 genes coding for the 3 Ca channels expressed in Apis mellifera. This work provides the first detailed characterization of the honeybee T-type Ca3 Ca channel and demonstrates the low toxicity of inhibiting this channel. Comparing Ca currents recorded in bee neurons and myocytes with Ca currents recorded in Xenopus oocytes expressing the honeybee Ca3 gene suggests native expression in bee muscle cells only. High-voltage activated Ca channels could be recorded in the somata of different cultured bee neurons. These functional data were confirmed by in situ hybridization, immunolocalization and in vivo analysis of the effects of a Ca3 inhibitor. The biophysical and pharmacological characterization and the tissue distribution of Ca3 suggest a role in honeybee muscle function.
电压门控钙通道是细胞兴奋性的关键转导器，参与了几种重要的生理反应。在脊椎动物中，已经描述和鉴定了 10 种钙通道基因，分为 3 个家族（Ca1、Ca2 和 Ca3）。昆虫只拥有每个家族的一个成员。这些基因已经在少数物种中被分离出来，尽管除了它们的关键作用之外，它们可能代表神经毒性杀虫剂的一个附带靶标，但只有少数得到了鉴定。我们已经分离出在 Apis mellifera 中表达的 3 种编码钙通道的基因。这项工作首次详细描述了蜜蜂 T 型 Ca3 钙通道，并证明了抑制这种通道的低毒性。比较在蜜蜂神经元和心肌细胞中记录的钙电流与在表达蜜蜂 Ca3 基因的非洲爪蟾卵母细胞中记录的钙电流表明，这种通道仅在蜜蜂肌肉细胞中表达。在不同培养的蜜蜂神经元的胞体中可以记录到高电压激活的钙通道。这些功能数据通过原位杂交、免疫定位和 Ca3 抑制剂体内分析得到了证实。Ca3 的生物物理和药理学特性以及组织分布表明其在蜜蜂肌肉功能中的作用。
