Henley John, Poo Mu-ming
Division of Neurobiology, Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720-3200, USA.
Trends Cell Biol. 2004 Jun;14(6):320-30. doi: 10.1016/j.tcb.2004.04.006.
Pathfinding by growing axons in the developing or regenerating nervous system is guided by gradients of molecular guidance cues. The neuronal growth cone, located at the ends of axons, uses surface receptors to sense these cues and to transduce guidance information to cellular machinery that mediates growth and turning responses. Cytoplasmic Ca2+ signals have key roles in regulating this motility. Global growth cone Ca2+ signals can regulate cytoskeletal elements and membrane dynamics to control elongation, whereas Ca2+ signals localized to one side of the growth cone can cause asymmetric activation of effector enzymes to steer the growth cone. Modulating Ca2+ levels in the growth cone might overcome inhibitory signals that normally prevent regeneration in the central nervous system.
在发育或再生的神经系统中,生长中的轴突进行路径寻找是由分子引导线索的梯度所引导的。位于轴突末端的神经元生长锥利用表面受体来感知这些线索,并将引导信息传递给介导生长和转向反应的细胞机制。细胞质Ca2+信号在调节这种运动性方面发挥着关键作用。全局生长锥Ca2+信号可以调节细胞骨架成分和膜动力学以控制伸长,而局限于生长锥一侧的Ca2+信号可导致效应酶的不对称激活,从而引导生长锥。调节生长锥中的Ca2+水平可能会克服通常阻止中枢神经系统再生的抑制性信号。