Induction of raft-like domains by a myristoylated NAP-22 peptide and its Tyr mutant
Induction of raft-like domains by a myristoylated NAP-22 peptide and its Tyr mutant
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DOI：
10.1111/j.1742-4658.2005.04612.x
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发表时间：
2005-04-01
期刊：
影响因子：
5.4
通讯作者：
Epand, RM
中科院分区：
文献类型：
--
作者：
Epand, RF;Sayer, BG;Epand, RM
N 末端肉豆蔻酰化的 19 个氨基酸肽，对应于神经元蛋白 NAP-22 的氨基末端（NAP-22 肽），是一种天然存在的肽，荧光显示该肽能够以胆固醇依赖性方式隔离 Bodipy 标记的 PtdIns(4,5)P2。目前的工作使用差示扫描量热法 (DSC)，扩展了富含 PtdIns(4,5)P2 结构域的形成是胆固醇依赖性的观察结果，并表明它也导致胆固醇耗尽结构域的形成。本工作中使用的 PtdIns(4,5)P2 是从天然来源中提取的，不含任何标记，并具有天然酰基链组成。当唯一的芳香族氨基酸 Tyr11 被 Leu 取代时，肽诱导的胆固醇耗尽结构域的形成被消除。尽管如此，修饰后的肽仍然可以将 PtdIns(4,5)P2 隔离到结构域中，这可能是因为肽中存在一簇阳离子残基。 H-1 NOESY MAS/NMR 显示，胆固醇和 PtdIns(4,5)P2 还可以调节肽插入双层。 Tyr 残基的芳香质子和脂质的质子之间的交叉峰强度表明，在胆固醇存在的情况下，肽与膜的相互作用的性质发生了变化。这些结果对于 NAP-22 影响神经元肌动蛋白重组的机制具有重要意义。
The N-terminally myristoylated, 19-amino acid peptide, corresponding to the amino terminus of the neuronal protein NAP-22 (NAP-22 peptide) is a naturally occurring peptide that had been shown by fluorescence to cause the sequestering of a Bodipy-labeled PtdIns(4,5)P2 in a cholesterol-dependent manner. The present work, using differential scanning calorimetry (DSC), extends the observation that formation of a PtdIns(4,5)P2-rich domain is cholesterol dependent and shows that it also leads to the formation of a cholesterol-depleted domain. The PtdIns(4,5)P2 used in the present work is extracted from natural sources and does not contain any label and has the native acyl chain composition. Peptide-induced formation of a cholesterol-depleted domain is abolished when the sole aromatic amino acid, Tyr11 is replaced with a Leu. Despite this, the modified peptide can still sequester PtdIns(4,5)P2 into domains, probably because of the presence of a cluster of cationic residues in the peptide. Cholesterol and PtdIns(4,5)P2 also modulate the insertion of the peptide into the bilayer as revealed by H-1 NOESY MAS/NMR. The intensity of cross peaks between the aromatic protons of the Tyr residue and the protons of the lipid indicate that in the presence of cholesterol there is a change in the nature of the interaction of the peptide with the membrane. These results have important implications for the mechanism by which NAP-22 affects actin reorganization in neurons.