Phosphatidylinositol 3-Kinase, Cdc42, and Rac1 Act Downstream of Ras in Integrin-Dependent Neurite Outgrowth in N1E-115 Neuroblastoma Cells
Phosphatidylinositol 3-Kinase, Cdc42, and Rac1 Act Downstream of Ras in Integrin-Dependent Neurite Outgrowth in N1E-115 Neuroblastoma Cells
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磷脂酰肌醇 3-激酶、Cdc42 和 Rac1 在 N1E-115 神经母细胞瘤细胞中整合素依赖性神经突生长中发挥 Ras 下游作用
DOI：
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发表时间：
2000
影响因子：
5.3
通讯作者：
L. Lim
中科院分区：
文献类型：
--
作者：
S. Sarner;R. Kozma;Sohail Ahmed;L. Lim
摘要Ras和Rho家族的GTP酶在细胞形态和生长的信号转导通路中起着重要作用。在这里，我们调查的作用，GTP酶Ras，Cdc 42，Rac 1，Rho和磷脂酰肌醇3-激酶（PI 3-激酶）的途径，导致从血清饥饿的N1 E-115神经母细胞瘤细胞突起生长。生长在层粘连蛋白基质上的血清饥饿细胞表现出整合素依赖性神经突生长。显性负突变体的Ras，PI 3-激酶，Cdc 42，或Rac 1的表达都阻止了这种神经突的生长，而组成型激活的Ras，PI 3-激酶，或Cdc 42的突变体都足以促进生长，即使在血清的存在下。优先结合PI 3-激酶的RasH 40 C; G12 V双突变体也促进神经突形成。活化的RasG 12 V诱导的生长需要PI 3-激酶活性，但活化的PI 3-激酶诱导的生长不需要Ras活性。虽然激活的Rac 1本身并不诱导神经突起，但激活的Cdc 42 G12 V诱导的神经突起生长是Rac 1依赖的。Cdc 42 G12 V诱导的神经突似乎失去了正常的极化，几乎是单个细胞产生的神经突平均数量的两倍。由激活的Ras或PI 3-激酶诱导的生长需要Cdc 42和Rac 1的活性，但Cdc 42 G12 V诱导的生长不需要Ras或PI 3-激酶的活性。活性RhoG 14 V减少RasG 12 V促进的生长。最后，显性负性Jun N-末端激酶或细胞外信号调节激酶的表达并不抑制生长，表明这些途径对该过程不是必需的。我们的研究结果表明一个层次的信号，Ras信号通过PI 3-激酶Cdc 42和Rac 1激活（和Rho失活），最终在神经突生长。因此，在没有血清因子的情况下，Ras可以启动N1 E-115神经母细胞瘤细胞的细胞周期停滞和终末分化。
ABSTRACT Ras and Rho family GTPases have been ascribed important roles in signalling pathways determining cellular morphology and growth. Here we investigated the roles of the GTPases Ras, Cdc42, Rac1, and Rho and that of phosphatidylinositol 3-kinase (PI 3-kinase) in the pathway leading from serum starvation to neurite outgrowth in N1E-115 neuroblastoma cells. Serum-starved cells grown on a laminin matrix exhibited integrin-dependent neurite outgrowth. Expression of dominant negative mutants of Ras, PI 3-kinase, Cdc42, or Rac1 all blocked this neurite outgrowth, while constitutively activated mutants of Ras, PI 3-kinase, or Cdc42 were each sufficient to promote outgrowth even in the presence of serum. A RasH40C;G12V double mutant which binds preferentially to PI 3-kinase also promoted neurite formation. Activated RasG12V-induced outgrowth required PI 3-kinase activity, but activated PI 3-kinase-induced outgrowth did not require Ras activity. Although activated Rac1 by itself did not induce neurites, neurite outgrowth induced by activated Cdc42G12Vwas Rac1 dependent. Cdc42G12V-induced neurites appeared to lose their normal polarization, almost doubling the average number of neurites produced by a single cell. Outgrowth induced by activated Ras or PI 3-kinase required both Cdc42 and Rac1 activity, but Cdc42G12V-induced outgrowth did not need Ras or PI 3-kinase activity. Active RhoG14V reduced outgrowth promoted by RasG12V. Finally, expression of dominant negative Jun N-terminal kinase or extracellular signal-regulated kinase did not inhibit outgrowth, suggesting these pathways are not essential for this process. Our results suggest a hierarchy of signalling where Ras signals through PI 3-kinase to Cdc42 and Rac1 activation (and Rho inactivation), culminating in neurite outgrowth. Thus, in the absence of serum factors, Ras may initiate cell cycle arrest and terminal differentiation in N1E-115 neuroblastoma cells.
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影响因子：
16.6
作者：
M. Barbacid
通讯作者：
M. Barbacid
影响因子：
4.6
作者：
Nancy Kaufmann;Zachary P. Wills;D. V. Vactor
通讯作者：
Nancy Kaufmann;Zachary P. Wills;D. V. Vactor
影响因子：
2.8
作者：
Olsen, T;DamJohansen, M;Hjortdal, JO
通讯作者：
Hjortdal, JO
影响因子：
56.9
作者：
BARSAGI, D;FERAMISCO, JR
通讯作者：
FERAMISCO, JR
影响因子：
2
作者：
Valente, Andre;Huang, Kuo-Hua;Engert, Florian
通讯作者：
Engert, Florian