Laboratory for Neuronal Growth Mechanisms, RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan.
Nat Rev Neurosci. 2011 Apr;12(4):191-203. doi: 10.1038/nrn2996. Epub 2011 Mar 9.
Graded distributions of extracellular cues guide developing axons toward their targets. A network of second messengers - Ca(2+) and cyclic nucleotides - shapes cue-derived information into either attractive or repulsive signals that steer growth cones bidirectionally. Emerging evidence suggests that such guidance signals create a localized imbalance between exocytosis and endocytosis, which in turn redirects membrane, adhesion and cytoskeletal components asymmetrically across the growth cone to bias the direction of axon extension. These recent advances allow us to propose a unifying model of how the growth cone translates shallow gradients of environmental information into polarized activity of the steering machinery for axon guidance.
细胞外线索的梯度分布引导发育中的轴突向其靶标生长。第二信使网络 - Ca(2+) 和环核苷酸 - 将线索衍生的信息塑造成吸引或排斥信号，从而双向引导生长锥。新出现的证据表明，这种导向信号在胞吐作用和胞吞作用之间产生局部失衡，进而使质膜、黏附分子和细胞骨架成分在生长锥内不对称地重新分布，从而使轴突延伸的方向发生偏差。这些最新进展使我们能够提出一个统一的模型，说明生长锥如何将环境信息的浅层梯度转化为导向轴突导向的转向机制的极化活性。
