Altun-Gultekin Z F, Wagner J A
Department of Neurology and Neuroscience, Cornell University Medical College, NY 10021, USA.
J Neurosci Res. 1996 May 15;44(4):308-27. doi: 10.1002/(SICI)1097-4547(19960515)44:4<308::AID-JNR2>3.0.CO;2-G.
The combination of nerve growth factor (NGF) and phorbol 12-myristate 13-acetate (PMA) rapidly induced the locomotion of PC12 cells by sequentially stimulating lamellar spreading, ruffling with pinocytosis, and polarization by retraction from the substratum. During migration, cells acquired long processes as a result of several undisrupted cell-substratum attachment points. The effect of NGF on PC12 migration was blocked by K-252a, a selective inhibitor of the trk family of receptor tyrosine kinases. When PMA was added to cells expressing pp60v-src, the cells displayed the same morphological behavior as they did with NGF and PMA addition. Activated ras only partially substituted for the effects of NGF; but, when ras was inhibited, the number of migrating cells decreased significantly due to a defect in spreading and retraction. Expression of an activated form of rac stimulated spontaneous growth of lamellipodia and enhanced cell migration in response to PMA. Expression of a dominant negative form of rac inhibited cell spreading and motility. Also, as a later effect, rac-inhibited cells extended much shorter neurites than wild type cells in response to NGF alone. These results indicate that the cytoarchitectural changes induced by NGF and PMA in PC12 cells are mediated by src, ras, and rac. Whereas ras and rac activation affect lamellipodia extension and retraction but not pinocytotic ruffling, src activation is involved in all three events.
神经生长因子（NGF）与佛波醇12 - 肉豆蔻酸酯13 - 乙酸酯（PMA）联合作用通过依次刺激片状伪足伸展、伴有胞饮作用的褶皱形成以及从基质上回缩导致细胞极化，迅速诱导PC12细胞运动。在迁移过程中，由于几个未中断的细胞 - 基质附着点，细胞获得了长突起。NGF对PC12迁移的作用被K - 252a阻断，K - 252a是受体酪氨酸激酶trk家族的选择性抑制剂。当将PMA添加到表达pp60v - src的细胞中时，细胞表现出与添加NGF和PMA时相同的形态学行为。活化的ras仅部分替代了NGF的作用；但是，当ras被抑制时，由于伸展和回缩缺陷，迁移细胞的数量显著减少。活化形式的rac的表达刺激了片状伪足的自发生长，并增强了细胞对PMA的迁移反应。显性负性形式的rac的表达抑制了细胞伸展和运动性。此外，作为后期效应，rac抑制的细胞在单独对NGF反应时，其神经突延伸比野生型细胞短得多。这些结果表明，NGF和PMA在PC12细胞中诱导的细胞结构变化由src、ras和rac介导。虽然ras和rac激活影响片状伪足的伸展和回缩，但不影响胞饮性褶皱形成，而src激活参与所有这三个事件。
