Differential Palmit(e)oylation of Wnt1 on C93 and S224 Residues Has Overlapping and Distinct Consequences
Differential Palmit(e)oylation of Wnt1 on C93 and S224 Residues Has Overlapping and Distinct Consequences
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DOI：
10.1371/journal.pone.0026636
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发表时间：
2011-10-26
期刊：
影响因子：
3.7
通讯作者：
Burrus, Laura W.
中科院分区：
文献类型：
--
作者：
Galli, Lisa M.;Burrus, Laura W.
尽管棕榈酸加合物的翻译后加成调节胞浆/细胞内蛋白的机制已被熟知，但这种脂质修饰如何影响分泌的配体，如WNTS，人们知之甚少。在这里，我们使用突变分析来表明WNT1的两个已知的棕榈酸(E)酰化残基C93和S224的差异修饰具有重叠和不同的结果。虽然每个残基在稳定性和分泌方面的相对作用相似，但在L细胞中的两种不同的生物学实验表明，C93的修饰主要通过β-连环蛋白非依赖的途径调节信号，而S224对β-连环蛋白依赖的信号转导起关键作用。此外，IWP1对Wnt的上游调节因子--豪猪碱(PORCN)的药理抑制可特异性地抑制β-连环蛋白依赖的信号转导。与这些观察结果一致的是，包含C93和S224的多肽结构域的氨基酸图谱表明，C93的酰化反应可能不依赖于PORCN，而S224的酰化可能依赖于PORCN。综上所述，我们的数据强烈表明C93和S224被不同的酶修饰，这些位点的不同修饰可能会影响Wnt信号通路的选择。
Though the mechanisms by which cytosolic/intracellular proteins are regulated by the post-translational addition of palmitate adducts is well understood, little is known about how this lipid modification affects secreted ligands, such as Wnts. Here we use mutational analysis to show that differential modification of the two known palmit(e)oylated residues of Wnt1, C93 and S224, has both overlapping and distinct consequences. Though the relative roles of each residue are similar with respect to stability and secretion, two distinct biological assays in L cells show that modification of C93 primarily modulates signaling via a beta-catenin independent pathway while S224 is crucial for beta-catenin dependent signaling. In addition, pharmacological inhibition of Porcupine (Porcn), an upstream regulator of Wnt, by IWP1, specifically inhibited beta-catenin dependent signaling. Consistent with these observations, mapping of amino acids in peptide domains containing C93 and S224 demonstrate that acylation of C93 is likely to be Porcn-independent while that of S224 is Porcn-dependent. Cumulatively, our data strongly suggest that C93 and S224 are modified by distinct enzymes and that the differential modification of these sites has the potential to influence Wnt signaling pathway choice.