Rab13 Regulates Neurite Outgrowth in PC12 Cells through Its Effector Protein, JRAB/MICAL-L2
Rab13 Regulates Neurite Outgrowth in PC12 Cells through Its Effector Protein, JRAB/MICAL-L2
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DOI：
10.1128/mcb.01067-09
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发表时间：
2010-02-15
影响因子：
5.3
通讯作者：
Sasaki, Takuya
中科院分区：
文献类型：
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作者：
Sakane, Ayuko;Honda, Kazufumi;Sasaki, Takuya
突起生长是神经元分化和再生的第一步，导致突触极化和可塑性。Rab13小G蛋白在神经元再生过程中表达水平升高，因此被认为参与了这一过程。我们先前发现JRAB(JRAB)/Mical-L2(与CASL-like 2相互作用的分子)是一种新的Rab13效应蛋白。在这里，我们证明了Rab13通过与JRAb/Mical-L2相互作用来调节大鼠嗜铬细胞瘤细胞系PC12中的轴突生长。单独表达JRAb/Mical-L2抑制轴突生长，而共表达优势活性形式Rab13则挽救了这一作用。我们还证明了JRAB/Mical-L2的N端钙蛋白同源(CH)和LIM结构域与C端螺旋线圈结构域之间存在分子内相互作用。最后，我们证明了Rab13与JRAb/Mical-L2的结合刺激了JRAb/Mical-L2与Actinin-4的相互作用，Actinin-4是一种肌动蛋白结合蛋白，定位于PC12细胞的细胞体和突起尖端。这些结果表明，Rab13和JRAb/Mical-L2可能参与了肌动蛋白细胞骨架的重组，从而导致轴突突起生长。
Neurite outgrowth is the first step in the processes of neuronal differentiation and regeneration and leads to synaptic polarization and plasticity. Rab13 small G protein shows an increased mRNA expression level during neuronal regeneration; it is therefore thought to be involved in this process. We previously identified JRAB (junctional Rab13-binding protein)/MICAL-L2 (molecules interacting with CasL-like 2) as a novel Rab13 effector protein. Here, we show that Rab13 regulates neurite outgrowth in the rat pheochromocytoma cell line PC12 through an interaction with JRAB/MICAL-L2. The expression of JRAB/MICAL-L2 alone inhibits neurite outgrowth, whereas coexpression of the dominant active form of Rab13 rescues this effect. We also demonstrate an intramolecular interaction between the N-terminal calponin-homology (CH) and LIM domains of JRAB/MICAL-L2 and the C-terminal coiled-coil domain. Finally, we show that the binding of Rab13 to JRAB/MICAL-L2 stimulates the interaction of JRAB/MICAL-L2 with actinin-4, an actin-binding protein, which localizes to the cell body and the tips of the neurites in PC12 cells. These results suggest that Rab13 and JRAB/MICAL-L2 may act to transfer actinin-4 from the cell body to the tips of neurites, where actinin-4 is involved in the reorganization of the actin cytoskeleton which results in neurite outgrowth.