离子和伊诺西1,4,5-三酸盐的信使作用范围
N L Allbritton1, T Meyer, L Stryer
1Department of Cell Biology, Stanford University, CA 94305.
概括
伊诺西1,4,5-三酸盐 (IP3) 在小于20微米的细胞中起到全球信使的作用,而 (Ca2+) 由于其缓冲作用,在受限制的领域中起作用.
科学领域:
- 细胞信号传递和分子生物学.
- 扩散和分子相互作用的生物物理学.
背景情况:
- 离子 (Ca2+) 和伊诺西1,4,5-三酸盐 (IP3) 是关键的细胞内信使.
- 了解它们的扩散动态是解读细胞反应的关键.
研究的目的:
- 为了确定Ca2+和IP3点源的有效作用范围.
- 为了比较这些信使在细胞提取物中的扩散特性.
主要方法:
- 在Xenopus laevis卵细胞细胞溶液提取物中测量 [3H]IP3和Ca2+的扩散系数 (D).
- 在不同度 (90nM到1microM) 的Ca2+扩散的分析.
主要成果:
- IP3 扩散系数 (D) 为 283 微米2/秒.
- 2+扩散系数 (D) 在13至65微米/秒之间,随着度的增加.
- 计算的有效范围:自由的Ca2+ (0.1微米),缓冲的Ca2+ (5微米) 和IP3 (24微米).
结论:
- 在小于20微米的细胞中,IP3充当全球信使.
- 由于移动和不移动组件的缓冲,Ca2+充当局部信使.
- 与IP3相比,缓冲显著限制了Ca2+的扩散范围.
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