SCLIP, a microtubule-destabilizing factor, interacts with RasGRF1 and inhibits its ability to promote Rac activation and neurite outgrowth
SCLIP, a microtubule-destabilizing factor, interacts with RasGRF1 and inhibits its ability to promote Rac activation and neurite outgrowth
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DOI：
10.1074/jbc.m604495200
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发表时间：
2007-01-26
影响因子：
4.8
通讯作者：
Zippel, Renata
中科院分区：
文献类型：
--
作者：
Baldassa, Simona;Gnesutta, Nerina;Zippel, Renata
RasGRF1是一种神经元特异性的鸟嘌呤核苷酸交换因子，与小的GTP酶RAS和RAC结合。它与记忆形成的调节和对药物滥用的耐受性的发展有关，尽管其机制仅被部分阐明。在这里，我们报道了通过酵母双杂交筛选分离的微管破坏稳定因子SCLIP(SCG10样蛋白)作为一种新的RasGRF1相互作用蛋白。这种相互作用需要跨越RasGRF1的DBL同源结构域的区域，该区域对RAC具有催化活性。在寻找可能的功能时，我们通过生化手段发现，SCLIP影响RasGRF1的信号特性，使其激活Rac/p38MAPK途径的能力大大降低，而Ras/Erk途径保持不变。此外，通过RasGRF1诱导神经突起生长的神经PC12细胞的转基因研究表明，RasGRF1诱导轴突生长的潜在作用，以及SCLIP的共表达抵消了这一影响，导致含有轴突的细胞比例急剧下降，这一比例似乎也显著缩短。本研究揭示了RasGRF1和SCLIP之间的物理和功能相互作用。我们认为，这种新的相互作用可能在调节神经元形态和结构可塑性的机制中具有潜在的意义。
RasGRF1 is a neuron-specific guanine nucleotide exchange factor for the small GTPases Ras and Rac. It is implicated in the regulation of memory formation and in the development of tolerance to drug abuse, although the mechanisms have been elucidated only in part. Here we report the isolation, by the yeast two-hybrid screen, of the microtubule-destabilizing factor SCLIP (SCG10-like protein) as a novel RasGRF1-interacting protein. This interaction requires the region spanning the Dbl-homology domain of RasGRF1, endowed with catalytic activity on Rac. In search for a possible function we found by biochemical means that SCLIP influences the signaling properties of RasGRF1, greatly reducing its ability to activate the Rac/p38 MAPK pathway, while the Ras/Erk one remains unaffected. Moreover, a potential role is suggested by transfection studies in neuronal PC12 cells in which RasGRF1 induces neurite outgrowth, and coexpression of SCLIP counteracts this effect, causing a dramatic decrease in the percentage of cells bearing neurites, which also appear significantly shortened. This study unveils a physical and functional interaction between RasGRF1 and SCLIP. We suggest that this novel interplay may have possible implications in mechanisms that regulate neuronal morphology and structural plasticity.