Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, USA.
Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, USA.
Sensors (Basel). 2021 May 3;21(9):3177. doi: 10.3390/s21093177.
Using radiofrequency dielectric spectroscopy, we have investigated the impact of the interaction between a G protein-coupled receptor (GPCR), the sterile2 α-factor receptor protein (Ste2), and its cognate agonist ligand, the α-factor pheromone, on the dielectric properties of the plasma membrane in living yeast cells (). The dielectric properties of a cell suspension containing a saturating concentration of α-factor were measured over the frequency range 40Hz-110 MHz and compared to the behavior of a similarly prepared suspension of cells in the absence of α-factor. A spherical three-shell model was used to determine the electrical phase parameters for the yeast cells in both types of suspensions. The relative permittivity of the plasma membrane showed a significant increase after exposure to α-factor (by 0.06 ± 0.05). The equivalent experiment performed on yeast cells lacking the ability to express Ste2 showed no change in plasma membrane permittivity. Interestingly, a large change also occurred to the electrical properties of the cellular interior after the addition of α-factor to the cell suspending medium, whether or not the cells were expressing Ste2. We present a number of different complementary experiments performed on the yeast to support these dielectric data and interpret the results in terms of specific cellular reactions to the presence of α-factor.
使用射频介电谱，我们研究了 G 蛋白偶联受体（GPCR）、无活性 2α 因子受体蛋白（Ste2）与其同源激动配体α 因子交配信息素之间的相互作用对活酵母细胞中质膜介电特性的影响。（）在 40Hz-110MHz 的频率范围内测量了含有饱和浓度α 因子的细胞悬浮液的介电特性，并将其与类似制备的不含α 因子的细胞悬浮液的行为进行了比较。使用球形三壳模型确定了两种悬浮液中酵母细胞的电相参数。与未接触α-因子的细胞相比，暴露于α-因子后质膜的相对介电常数显著增加（增加了 0.06±0.05）。在缺乏表达 Ste2 能力的酵母细胞上进行的等效实验表明，质膜的介电常数没有变化。有趣的是，向细胞悬浮液中添加α-因子后，即使细胞不表达 Ste2，细胞内部的电特性也会发生很大变化。我们提出了一些在酵母上进行的不同的补充实验，以支持这些介电数据，并根据细胞对α-因子存在的特定反应来解释结果。
