Ras signals to the cell cycle machinery via multiple pathways to induce anchorage-independent growth.
Ras signals to the cell cycle machinery via multiple pathways to induce anchorage-independent growth.
复制标题
Ras 通过多种途径向细胞周期机制发出信号，诱导不依赖贴壁的生长。
DOI：
10.1128/mcb.18.5.2586
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发表时间：
1998
影响因子：
5.3
通讯作者：
Krauss,RS
中科院分区：
文献类型：
--
作者：
Yang,JJ;Kang,JS;Krauss,RS
几个特定的细胞周期活动依赖于非转化细胞中的细胞-基质粘附，Ras癌蛋白诱导锚定非依赖性生长的能力与其废除这种粘附要求的能力有关。Ras信号通过多个下游效应蛋白，其协同组合可能是完全转化细胞的高度改变的表型所需的。我们在这里描述的细胞周期调控的锚定非依赖性生长，利用Ras效应环突变体在NIH 3 T3和大鼠6细胞的研究。活化的H-Ras（12 V）的稳定表达诱导两种细胞类型的软琼脂集落形成，但三种效应环突变体（12 V，35 S，12 V，37 G和12 V，40 C）中的每一种都在产生这种反应方面有缺陷。这些突变体的所有三种可能的成对组合的表达协同诱导NIH 3 T3细胞的锚定非依赖性生长，但在Rat 6细胞中仅12 V，35 S-12 V，37 G和12 V，37 G-12 V，40 C组合是互补的。每个单独的效应环突变体部分缓解pRB磷酸化的粘附依赖性，细胞周期蛋白E依赖性激酶活性，和细胞周期蛋白A在NIH 3 T3细胞中的表达，但不是大鼠6，细胞。效应环突变体的成对组合在大鼠6细胞中协同产生锚定非依赖性生长，也导致协同消除这些细胞周期活动的粘附要求。互补产生锚定非依赖性生长和增强细胞周期活动之间的关系并不清楚在NIH 3 T3细胞表达对突变体，这意味着存在这些活动的阈值或额外的要求，在诱导锚定非依赖性生长。细胞周期蛋白D1、E或A的异位表达与单个效应环突变体协同诱导NIH 3 T3细胞软琼脂集落形成，细胞周期蛋白A特别有效。总之，这些数据表明，Ras利用多种途径向细胞周期机制发出信号，并且这些途径协同作用以取代特定细胞周期事件的粘附要求，从而导致锚定非依赖性生长。
Several specific cell cycle activities are dependent on cell-substratum adhesion in nontransformed cells, and the ability of the Ras oncoprotein to induce anchorage-independent growth is linked to its ability to abrogate this adhesion requirement. Ras signals via multiple downstream effector proteins, a synergistic combination of which may be required for the highly altered phenotype of fully transformed cells. We describe here studies on cell cycle regulation of anchorage-independent growth that utilize Ras effector loop mutants in NIH 3T3 and Rat 6 cells. Stable expression of activated H-Ras (12V) induced soft agar colony formation by both cell types, but each of three effector loop mutants (12V,35S, 12V,37G, and 12V,40C) was defective in producing this response. Expression of all three possible pairwise combinations of these mutants synergized to induce anchorage-independent growth of NIH 3T3 cells, but only the 12V,35S-12V,37G and 12V,37G-12V,40C combinations were complementary in Rat 6 cells. Each individual effector loop mutant partially relieved adhesion dependence of pRB phosphorylation, cyclin E-dependent kinase activity, and expression of cyclin A in NIH 3T3, but not Rat 6, cells. The pairwise combinations of effector loop mutants that were synergistic in producing anchorage-independent growth in Rat 6 cells also led to synergistic abrogation of the adhesion requirement for these cell cycle activities. The relationship between complementation in producing anchorage-independent growth and enhancement of cell cycle activities was not as clear in NIH 3T3 cells that expressed pairs of mutants, implying the existence of either thresholds for these activities or additional requirements in the induction of anchorage-independent growth. Ectopic expression of cyclin D1, E, or A synergized with individual effector loop mutants to induce soft agar colony formation in NIH 3T3 cells, cyclin A being particularly effective. Taken together, these data indicate that Ras utilizes multiple pathways to signal to the cell cycle machinery and that these pathways synergize to supplant the adhesion requirements of specific cell cycle events, leading to anchorage-independent growth.