The polarity-inducing kinase Par-1 controls Xenopus gastrulation in cooperation with 14-3-3 and aPKC
The polarity-inducing kinase Par-1 controls Xenopus gastrulation in cooperation with 14-3-3 and aPKC
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DOI：
10.1038/sj.emboj.7600381
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发表时间：
2004-10-27
期刊：
影响因子：
11.4
通讯作者：
Nishida, E
中科院分区：
文献类型：
--
作者：
Kusakabe, M;Nishida, E
Par（partitioning-deficient）基因最初在秀丽隐杆线虫中被鉴定为前/后极性的决定因素。然而，它们在脊椎动物发育中的功能及其作用机制尚未完全阐明。在这里，我们表明，两个成员的Par蛋白，14-3-3（Par-5）和非典型的PKC（aPKC），调节丝氨酸/苏氨酸激酶Par-1控制非洲爪蟾原肠胚。我们首先发现，非洲爪蟾Par-1（xPar-1）是必不可少的原肠胚形成，但在早期胚胎发育过程中的细胞命运规范。然后我们发现xPar-1以aPKC依赖性方式与14-3-3结合。我们的分析确定了xPar-1中的两个aPKC磷酸化位点，这对于14-3-3结合和正确的原肠胚形成运动是必不可少的。xPar-1与14-3-3的aPKC磷酸化依赖性结合不显著影响xPar-1的激酶活性，但诱导xPar-1从质膜重新定位至细胞质。最后，我们表明，非洲爪蟾aPKC和它的结合伙伴非洲爪蟾Par-6原肠胚也是必不可少的。因此，我们的研究结果确定了非洲爪蟾原肠胚形成的Par蛋白的要求，并揭示了一种新的Par蛋白内的相互关系，可能提供了一个一般的空间控制Par-1的机制。
Par (partitioning-defective) genes were originally identified in Caenorhabditis elegans as determinants of anterior/ posterior polarity. However, neither their function in vertebrate development nor their action mechanism has been fully addressed. Here we show that two members of Par proteins, 14-3-3 (Par-5) and atypical PKC ( aPKC), regulate the serine/threonine kinase Par-1 to control Xenopus gastrulation. We find first that Xenopus Par-1 (xPar-1) is essential for gastrulation but not for cell fate specification during early embryonic development. We then find that xPar-1 binds to 14-3-3 in an aPKC-dependent manner. Our analyses identify two aPKC phosphorylation sites in xPar-1, which are essential for 14-3-3 binding and for proper gastrulation movements. The aPKC phosphorylation-dependent binding of xPar-1 to 14-3-3 does not markedly affect the kinase activity of xPar-1, but induces relocation of xPar-1 from the plasma membranes to the cytoplasm. Finally, we show that Xenopus aPKC and its binding partner Xenopus Par-6 are also essential for gastrulation. Thus, our results identify a requirement of Par proteins for Xenopus gastrulation and reveal a novel interrelationship within Par proteins that may provide a general mechanism for spatial control of Par-1.