Phosphorylation by Rho kinase regulates CRMP-2 activity in growth cones
Phosphorylation by Rho kinase regulates CRMP-2 activity in growth cones
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DOI：
10.1128/mcb.25.22.9973-9984.2005
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发表时间：
2005-11-01
影响因子：
5.3
通讯作者：
Kaibuchi, K
中科院分区：
文献类型：
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作者：
Arimura, N;Ménager, C;Kaibuchi, K
坍缩反应介质蛋白2 （CRMP-2）通过调节微管组装和麻木介导的内吞作用来促进生长锥的推进。我们之前的研究表明，Rho激酶在生长锥坍塌过程中磷酸化CRMP-2；然而，磷酸化的CRMP-2在生长锥塌陷中的作用仍有待阐明。在这里，我们报道了Rho激酶的CRMP-2磷酸化取消了与微管蛋白二聚体、微管或Numb的结合活性。CRMP-2与肌动蛋白结合，但其结合不受磷酸化影响。电镜显示，CRMP-2定位于背根神经节神经元生长锥的微管、网格蛋白包被窝和肌动蛋白丝，而磷酸化的CRMP-2仅定位于肌动蛋白丝。CRMP-2的磷系突变体增强神经突伸长的能力较弱。此外，在生长锥塌陷过程中，ephrin-A5通过Rho激酶诱导CRMP-2磷酸化。综上所述，这些结果表明，Rho激酶磷酸化CRMP-2，并使CRMP-2在生长锥塌陷过程中促进微管组装和麻木介导的内吞作用的能力失活。
Collapsin response mediator protein 2 (CRMP-2) enhances the advance of growth cones by regulating microtubule assembly and Numb-mediated endocytosis. We previously showed that Rho kinase phosphorylates CRMP-2 during growth cone collapse; however, the roles of phosphorylated CRMP-2 in growth cone collapse remain to be clarified. Here, we report that CRMP-2 phosphorylation by Rho kinase cancels the binding activity to the tubulin dimer, microtubules, or Numb. CRMP-2 binds to actin, but its binding is not affected by phosphorylation. Electron microscopy revealed that CRMP-2 localizes on microtubules, clathrin-coated pits, and actin filaments in dorsal root ganglion neuron growth cones, while phosphorylated CRMP-2 localizes only on actin filaments. The phosphomimic mutant of CRMP-2 has a weakened ability to enhance neurite elongation. Furthermore, ephrin-A5 induces phosphorylation of CRMP-2 via Rho kinase during growth cone collapse. Taken together, these results suggest that Rho kinase phosphorylates CRMP-2, and inactivates the ability of CRMP-2 to promote microtubule assembly and Numb-mediated endocytosis, during growth cone collapse.