Maître Blandine, Angénieux Catherine, Wurtz Virginie, Layre Emilie, Gilleron Martine, Collmann Anthony, Mariotti Sabrina, Mori Lucia, Fricker Dominique, Cazenave Jean-Pierre, van Dorsselaer Alain, Gachet Christian, de Libero Gennaro, Puzo Germain, Hanau Daniel, de la Salle Henri
INSERM, U.725 Biology of Human Dendritic Cells, Strasbourg, , France.
Biochem J. 2009 May 1;419(3):661-8. doi: 10.1042/BJ20082204.
CD1e displays unique features in comparison with other CD1 proteins. CD1e accumulates in Golgi compartments of immature dendritic cells and is transported directly to lysosomes, where it is cleaved into a soluble form. In these latter compartments, CD1e participates in the processing of glycolipid antigens. In the present study, we show that the N-terminal end of the membrane-associated molecule begins at amino acid 20, whereas the soluble molecule consists of amino acids 32-333. Thus immature CD1e includes an N-terminal propeptide which is cleaved in acidic compartments and so is absent from its mature endosomal form. Mutagenesis experiments demonstrated that the propeptide controls the assembly of the CD1e alpha-chain with beta(2)-microglobulin, whereas propeptide-deleted CD1e molecules are immunologically active. Comparison of CD1e cDNAs from different mammalian species indicates that the CD1e propeptide is conserved during evolution, suggesting that it may also optimize the generation of CD1e molecules in other species.
与其他CD1蛋白相比，CD1e具有独特的特征。CD1e在未成熟树突状细胞的高尔基体区室中积累，并直接运输到溶酶体，在那里它被切割成可溶性形式。在这些后期区室中，CD1e参与糖脂抗原的加工。在本研究中，我们表明膜相关分子的N末端始于第20个氨基酸，而可溶性分子由第32 - 333个氨基酸组成。因此，未成熟的CD1e包括一个N末端前肽，它在酸性区室中被切割，因此在其成熟的内体形式中不存在。诱变实验表明，前肽控制CD1eα链与β2-微球蛋白的组装，而缺失前肽的CD1e分子具有免疫活性。来自不同哺乳动物物种的CD1e cDNA的比较表明，CD1e前肽在进化过程中是保守的，这表明它也可能优化其他物种中CD1e分子的产生。
