一个PI3K的Gβ马灵敏度取决于一个紧密相关的适配器,p101
L R Stephens1, A Eguinoa, H Erdjument-Bromage
1Department of Signalling, The Babraham Institute, Cambridge, United Kingdom.
Cell
|April 4, 1997
概括
研究人员在猪中性粒细胞中发现了两种新型的氨基酸3-激酶 (PI3Ks). 这些PI3Ks由Gβ玛蛋白激活,通过与独特的p101蛋白相互作用,显示出活性显著放大.
科学领域:
- 生物化学 生物化学
- 分子生物学分子生物学
- 细胞信号传递 细胞信号传递
背景情况:
- 酸-3-酶 (PI3Ks) 是细胞信号通路中的关键酶.
- G蛋白结合受体 (GPCRs) 激活下游信号级联,其中涉及Gβ玛子单元.
- 特定的PI3K异型受Gβ马调节,影响细胞反应.
研究的目的:
- 从猪中性粒细胞醇净化和表征Gβ玛激活PI3Ks.
- 确定这些新型PI3K酶的子单元和调节机制.
- 克隆和表达编码已识别的PI3K子单元的cDNA.
主要方法:
- 从猪中性粒细胞醇中净化PI3K酶.
- 生物化学测试以确定酶活性和激活由Gβ-玛.
- 基于序的寡核酸探针用于cDNA克隆.
- 在昆虫和哺乳动物细胞中的重组蛋白的表达和净化.
主要成果:
- 两种非常相似的PtdIns{4,5) P2-选择性PI3Ks被净化,这两种PI3K都是101 kDa蛋白的异构体和120 kDa或117 kDa的催化子单元.
- 这两种PI3K形式都被Gβ马激活了100倍以上.
- 克隆cDNA揭示了p120子单元与PI3K马相关,而p101子单元则是新的.
- 同表达和净化证明了p101和p120之间的紧密结合,p101放大了Gβ玛介导PI3K活性>100倍.
结论:
- 确定了一种新的调节子单元p101,可显著放大PI3K催化子单元 (p120) 的Gβ玛介导激活.
- 这一发现揭示了一种新机制,用于调节PI3K活动,以响应GPCR信号.
- 描述的PI3K复合体代表了一个独特的信号节点,在中性粒细胞功能中具有潜在的作用.
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