School of Natural Sciences, Technology and Environmental Studies, Södertörn University, Huddinge, Sweden.
Eur J Cell Biol. 2013 Jun-Jul;92(6-7):213-21. doi: 10.1016/j.ejcb.2013.07.002. Epub 2013 Jul 29.
Neurite outgrowth is mediated by dynamic changes of the cytoskeleton and is largely controlled by Rho GTPases and their regulators. Here, we show that the polarity protein Scribble controls PC12 cell neurite outgrowth in response to nerve growth factor. Scribble knockdown decreases neurite numbers and increases neurite length. This effect is linked to TrkA the cognate receptor for NGF as pharmacological inhibition of phosphorylated TrkA (pTrkA) reduces Scribble expression. Moreover, Scribble forms a complex with the MAPK components ERK1/2 in a growth factor dependent manner. In RNAi experiments where Scribble expression is efficiently depleted sustained ERK1/2 phosphorylation is reduced. Conversely, siRNA with intermediate Scribble silencing efficiency fails to match this effect indicating that ERK1/2 activation depends on basic Scribble protein levels. Finally, Scribble translocates to the plasma membrane in response to growth factor where it complexes with HRas and Rac1 suggesting that the phenotype activated by loss of Scribble may be a result of altered GTPase activity. Together, these results demonstrate a novel role for Scribble in neurite outgrowth of PC12 cells.
神经突的生长由细胞骨架的动态变化介导，主要受 Rho GTPases 及其调节因子控制。在这里，我们发现极性蛋白 Scribble 通过神经生长因子（NGF）控制 PC12 细胞的神经突生长。Scribble 敲低会减少神经突数量并增加神经突长度。这种作用与 NGF 的同源受体 TrkA 有关，因为磷酸化 TrkA（pTrkA）的药理学抑制作用会降低 Scribble 的表达。此外，Scribble 以生长因子依赖的方式与 MAPK 成分 ERK1/2 形成复合物。在 RNAi 实验中，当 Scribble 表达被有效地耗尽时，持续的 ERK1/2 磷酸化减少。相反，具有中等 Scribble 沉默效率的 siRNA 无法匹配这种效应，表明 ERK1/2 的激活依赖于基本的 Scribble 蛋白水平。最后，Scribble 响应生长因子而向质膜转位，在那里它与 HRas 和 Rac1 形成复合物，表明 Scribble 缺失激活的表型可能是由于 GTPase 活性改变所致。总之，这些结果表明 Scribble 在 PC12 细胞的神经突生长中具有新的作用。
