Robust spatial sensing of mating pheromone gradients by yeast cells.
Robust spatial sensing of mating pheromone gradients by yeast cells.
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DOI：
10.1371/journal.pone.0003865
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发表时间：
2008
期刊：
影响因子：
3.7
通讯作者：
Yi TM
中科院分区：
文献类型：
--
作者：
Moore TI;Chou CS;Nie Q;Jeon NL;Yi TM
突出或向上移动化学梯度是生物体的普遍行为。研究了酿酒酵母a细胞对微流控室中产生的交配信息素α-因子的空间梯度的感知和响应能力；重点是bar1Δ菌株，它不会降解输入的信息素。酵母细胞表现出良好的准确性，交配投影通常在梯度上指向正确的方向（在某些条件下约为80%），对浅梯度具有良好的敏感性，并且动态范围宽，因此在平均α-因子浓度的1000倍范围内梯度传感相对稳健。在接近受体Kd的较低浓度（5 nM）和较陡的梯度斜率下，定向传感效果最佳。信息素超敏感突变（sst2Δ和ste2300Δ）破坏了异源三聚体g蛋白信号的下调，导致了感知和反应的缺陷。有趣的是，酵母细胞采用适应性机制来增加这一过程的稳稳性，包括在低费洛蒙浓度下的丝状生长（即定向远端出芽），弯曲突起使其更符合梯度，以及在第一次突起方向错误时形成更准确的第二次突起。最后，细胞能够放大α-因子的浅层外部梯度信号，从而在细胞前部产生剧烈的信号蛋白极化。数学模型揭示了这种放大的机制，以及超敏感突变体如何破坏精确的极化。总之，这些数据有助于明确和阐明酵母细胞感知和响应信息素空间梯度的能力。
Projecting or moving up a chemical gradient is a universal behavior of living organisms. We tested the ability of S. cerevisiae a-cells to sense and respond to spatial gradients of the mating pheromone α-factor produced in a microfluidics chamber; the focus was on bar1Δ strains, which do not degrade the pheromone input. The yeast cells exhibited good accuracy with the mating projection typically pointing in the correct direction up the gradient (∼80% under certain conditions), excellent sensitivity to shallow gradients, and broad dynamic range so that gradient-sensing was relatively robust over a 1000-fold range of average α-factor concentrations. Optimal directional sensing occurred at lower concentrations (5 nM) close to the Kd of the receptor and with steeper gradient slopes. Pheromone supersensitive mutations (sst2Δ and ste2300Δ) that disrupt the down-regulation of heterotrimeric G-protein signaling caused defects in both sensing and response. Interestingly, yeast cells employed adaptive mechanisms to increase the robustness of the process including filamentous growth (i.e. directional distal budding) up the gradient at low pheromone concentrations, bending of the projection to be more aligned with the gradient, and forming a more accurate second projection when the first projection was in the wrong direction. Finally, the cells were able to amplify a shallow external gradient signal of α-factor to produce a dramatic polarization of signaling proteins at the front of the cell. Mathematical modeling revealed insights into the mechanism of this amplification and how the supersensitive mutants can disrupt accurate polarization. Together, these data help to specify and elucidate the abilities of yeast cells to sense and respond to spatial gradients of pheromone.
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影响因子：
12.3
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