Cytoplasmic linker proteins promote microtubule rescue in vivo.
Cytoplasmic linker proteins promote microtubule rescue in vivo.
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DOI：
10.1083/jcb.200208058
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发表时间：
2002-11-25
影响因子：
7.8
通讯作者：
Borisy, Gary G
中科院分区：
文献类型：
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作者：
Komarova, Yulia A;Akhmanova, Anna S;Kojima, Shin-Ichiro;Galjart, Niels;Borisy, Gary G
通过表达显性失活突变体来研究正端跟踪蛋白在调节微管 (MT) 动力学中的作用，该突变体从 MT 正端去除内源性细胞质连接蛋白 (CLIP)。在对照 CHO 细胞中，MT 表现出不对称行为：MT 持续向质膜生长，并在细胞周边附近表现出频繁的长度波动。在没有 CLIP 的情况下，微管救援频率减少了七倍。 MT 行为变得对称，包括持续增长和持续缩短。 CLIP 的去除也会导致 p150Glued 的损失，但不会导致 CLIP 相关蛋白 (CLASP2) 或 EB1 的损失。这一结果提出了一种可能性，即动态变化是由于 CLIP 或 p150Glued 丢失造成的。为了区分这些可能性，我们进行了救援实验。通过表达 CLIP-170 头域，恢复了正常的 MT 动态，但 p150Glued 没有被招募回 MT 加端。 p150Glued 头域的表达仅部分恢复了 MT 动力学。我们得出的结论是，CLIP 头域足以改变 MT 动态，无论是通过自身作为救援因素还是通过招募救援因素间接地改变 MT 动态。通过提高救援频率，CLIP 提供了一种机制，通过该机制，MT 加端可以集中在小区边缘附近。
The role of plus end–tracking proteins in regulating microtubule (MT) dynamics was investigated by expressing a dominant negative mutant that removed endogenous cytoplasmic linker proteins (CLIPs) from MT plus ends. In control CHO cells, MTs exhibited asymmetric behavior: MTs persistently grew toward the plasma membrane and displayed frequent fluctuations of length near the cell periphery. In the absence of CLIPs, the microtubule rescue frequency was reduced by sevenfold. MT behavior became symmetrical, consisting of persistent growth and persistent shortening. Removal of CLIPs also caused loss of p150Glued but not CLIP-associating protein (CLASP2) or EB1. This result raised the possibility that the change in dynamics was a result of the loss of either CLIPs or p150Glued. To distinguish between these possibilities, we performed rescue experiments. Normal MT dynamics were restored by expression of the CLIP-170 head domain, but p150Glued was not recruited back to MT plus ends. Expression of p150Glued head domain only partially restored MT dynamics. We conclude that the CLIP head domain is sufficient to alter MT dynamics either by itself serving as a rescue factor or indirectly by recruiting a rescue factor. By promoting a high rescue frequency, CLIPs provide a mechanism by which MT plus ends may be concentrated near the cell margin.