Gonzalez-Agosti C, Solomon F
Department of Biology and Center for Cancer Research, Massachusetts Institute of Technology, Cambridge 02139, USA.
Cell Motil Cytoskeleton. 1996;34(2):122-36. doi: 10.1002/(SICI)1097-0169(1996)34:2<122::AID-CM4>3.0.CO;2-D.
The ERM protein--ezrin, radixin, moesin--localize to a variety of cortical structures, where they may participate in connecting the cytoskeleton to components of the plasma membrane. Antibodies that recognize the ERM proteins specifically stain growth cones of various neurons [Goslin et al., 1989: J. Cell Biol. 109:1621-1631; Birgbauer et al., 1991: J. Neurosci. Res. 30:232-241]. To probe the function of ERM proteins in growth cones, we studied the consequences of perturbing growth cone morphology and motility of cultured chick sympathetic neurons. We demonstrate that radixin is present in these growth cones. Withdrawal of nerve growth factor (NGF) induces rapid collapse of the growth cones; concomitantly, radixin staining in these growth cones are greatly diminished. Upon readdition of NGF, rapid growth cone formation is accompanied by relocalization of radixin. Induction of growth cone collapse by either growth cone-growth cone contact or exposure to brain membrane extract results in a similar diminution of radixin staining. We induced a more subtle change in the organization of the growth cones by subjecting them to an electric field. These growth cones rapidly orient toward the cathode. We show that the radixin staining of the growth cones is also asymmetrically localized toward the leading edges in the new direction of growth. The results suggest that the localization of radixin may be essential for the normal expression of growth cone morphology and function.
ERM蛋白（埃兹蛋白、根蛋白、膜突蛋白）定位于多种皮质结构，在这些结构中它们可能参与将细胞骨架与质膜成分相连。识别ERM蛋白的抗体能特异性地对各种神经元的生长锥进行染色[戈斯林等人，1989年：《细胞生物学杂志》109卷：1621 - 1631页；比尔鲍尔等人，1991年：《神经科学研究》30卷：232 - 241页]。为了探究ERM蛋白在生长锥中的功能，我们研究了扰乱培养的鸡交感神经元生长锥形态和运动性的后果。我们证明根蛋白存在于这些生长锥中。去除神经生长因子（NGF）会导致生长锥迅速塌陷；与此同时，这些生长锥中的根蛋白染色大大减少。重新添加NGF后，生长锥迅速形成，同时根蛋白重新定位。生长锥 - 生长锥接触或暴露于脑膜提取物诱导生长锥塌陷，会导致类似的根蛋白染色减少。通过使生长锥受到电场作用，我们诱导了生长锥组织更细微的变化。这些生长锥迅速朝向阴极定向。我们表明，生长锥的根蛋白染色在新的生长方向上也不对称地定位于前沿。结果表明，根蛋白的定位可能对生长锥形态和功能的正常表达至关重要。
