Protein kinase A acts at the basal body of the primary cilium to prevent Gli2 activation and ventralization of the mouse neural tube
Protein kinase A acts at the basal body of the primary cilium to prevent Gli2 activation and ventralization of the mouse neural tube
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DOI：
10.1242/dev.070805
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发表时间：
2011-11-15
期刊：
影响因子：
4.6
通讯作者：
Anderson, Kathryn V.
中科院分区：
文献类型：
--
作者：
Tuson, Miquel;He, Mu;Anderson, Kathryn V.
蛋白激酶A（PKA）是进化上保守的Hedgehog（Hh）信号转导途径的负调控因子。已知PKA是蛋白水解加工事件所需的，所述蛋白水解加工事件产生在不存在Hh的情况下保持靶基因关闭的Ci和Gli转录因子的阻遏物形式。在这里，我们表明，PKA活性在小鼠中的完全丧失导致妊娠中期的致命性和完全腹侧神经管，表明PKA是作为强大的负调节器的音刺猬（Shh）通路修补1（Ptch 1）或抑制融合（Sufu）。遗传分析表明，尽管PKA对于Gli3的阻遏物形式的产生是重要的，但PKA在神经发育中的Shh通路中的主要功能是抑制Gli2的活化。PKA突变体中Hh通路的激活依赖于纤毛，PKA的催化和调节亚基定位于初级纤毛基部的隔室，紧邻基体。数据显示PKA不影响纤毛长度或纤毛中Smoothened（Smo）的运输。相反，我们发现，有一个显着增加的水平Gli2在PKA无效细胞的纤毛的尖端。这些数据表明，PKA的行为后，Gli蛋白的初级纤毛的基础上，在这个模型中，Gli蛋白的顺序运动之间的车厢在纤毛和在其基础控制访问Gli蛋白PKA，这决定了Gli蛋白的命运和活性的Shh通路。
Protein kinase A (PKA) is an evolutionarily conserved negative regulator of the hedgehog (Hh) signal transduction pathway. PKA is known to be required for the proteolytic processing event that generates the repressor forms of the Ci and Gli transcription factors that keep target genes off in the absence of Hh. Here, we show that complete loss of PKA activity in the mouse leads to midgestation lethality and a completely ventralized neural tube, demonstrating that PKA is as strong a negative regulator of the sonic hedgehog (Shh) pathway as patched 1 (Ptch1) or suppressor of fused (Sufu). Genetic analysis shows that although PKA is important for production of the repressor form of Gli3, the principal function of PKA in the Shh pathway in neural development is to restrain activation of Gli2. Activation of the Hh pathway in PKA mutants depends on cilia, and the catalytic and regulatory subunits of PKA are localized to a compartment at the base of the primary cilia, just proximal to the basal body. The data show that PKA does not affect cilia length or trafficking of smoothened (Smo) in the cilium. Instead, we find that there is a significant increase in the level of Gli2 at the tips of cilia of PKA-null cells. The data suggest a model in which PKA acts at the base of the cilium after Gli proteins have transited the primary cilium; in this model the sequential movement of Gli proteins between compartments in the cilium and at its base controls accessibility of Gli proteins to PKA, which determines the fates of Gli proteins and the activity of the Shh pathway.