The functional cooperation of MAP1A heavy chain and light chain 2 in the binding of microtubules
The functional cooperation of MAP1A heavy chain and light chain 2 in the binding of microtubules
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DOI：
10.1016/j.yexcr.2005.05.007
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发表时间：
2005-08-15
影响因子：
3.7
通讯作者：
Hirokawa, N
中科院分区：
文献类型：
--
作者：
Chien, CL;Lu, KS;Hirokawa, N
微管相关蛋白1A（Microtubule-associated protein 1A，MAP 1A）是一种高分子量蛋白，由一条重链和一条轻链（LC 2）组成，沿着微管广泛分布于成熟神经元和神经胶质细胞中。为了说明MAP IA重链、轻链和微管之间的相互作用，我们制备了具有Myc-、EGFP-或DsRed-标签的DNA构建体，用于表达完整MAP IA蛋白、MAP IA重链和轻链的两个结构域的全长MAP IA DNA。在非神经元型COS 7和神经元型Neuro 2A细胞中监测了各种MAP IA结构域的分布模式以及它们与微管的相互作用。我们的数据显示，一个完整的MAP IA蛋白，它包含重链和LC 2，可以与微管网络共定位不仅在Neuro 2A细胞，而且在转染的COS 7细胞。在单独用MAP 1A重链或LC 2转染的COS 7细胞中，沿微管沿着不能观察到丝状结构。而将MAP 1A重链与LC 2一起导入COS 7细胞后，两者均能与微管共定位。从我们的功能分析，MAP 1A及其LC 2可以保护微管免受纳可达唑的挑战。MAP 1A不同结构域的酵母双杂交实验数据证实了MAP 1A重链LC 2和NH 2端的相互作用对微管结合是重要的。从我们对MAP 1A功能结构域的分析中，我们认为MAP 1A重链和LC 2之间的相互作用对于微管的结合至关重要。(c)2005年爱思唯尔公司All rights reserved.
Microtubule-associated protein 1A (MAP1A) is a high-molecular-weight protein that is comprised of a heavy chain and a light chain (LC2) and is widely distributed along the microtubules in both mature neurons and glial cells. To illustrate the interaction among the MAP I A heavy chain, light chain, and microtubule, we prepared DNA constructs with Myc-, EGFP-, or DsRed-tags for full-length MAP1A DNA expressing whole MAP I A protein, two domains of MAP I A heavy chain, and light chain. Distribution patterns of various MAP I A domains as well as their interactions with microtubules were monitored in a non-neuronal COS7 and a neuronal Neuro2A cells. Our data revealed that a complete MAP I A protein, which contains both heavy chain and LC2, could be colocalized with microtubule networks not only in Neuro2A cells but also in transfected COS7 cells. Filamentous structures failed to be visualized along microtubules in COS7 cells transfected with MAP1A heavy chain or LC2 alone. Whereas, after introducing MAP1A heavy chain with LC2 into COS7 cells, both heavy chain and LC2 could be colocalized with microtubules. From our functional analysis, both MAP1A and its LC2 could protect microtubules against the challenge of nacodazol. Data collected from yeast two-hybrid assays of various MAP1A domains confirmed that the interaction of LC2 and NH2-terminal of MAP1A heavy chain is important for microtubule binding. From our analysis of MAP1A functional domains, we suggest that interactions between MAP1A heavy chain and LC2 are critical for the binding of microtubules. (c) 2005 Elsevier Inc. All rights reserved.