Lipid binding activity of a neuron‐specific protein NAP‐22 studied in vivo and in vitro
Lipid binding activity of a neuron‐specific protein NAP‐22 studied in vivo and in vitro
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体内和体外研究的神经元特异性蛋白 NAP-22 的脂质结合活性
DOI：
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发表时间：
2002
影响因子：
4.2
通讯作者：
S. Maekawa
中科院分区：
文献类型：
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作者：
Akira Terashita;N. Funatsu;M. Umeda;Y. Shimada;Y. Ohno‐Iwashita;R. Epand;S. Maekawa
细胞膜上存在一个称为“筏”的微结构域。其外层富含胆固醇和鞘脂，这是众所周知的。相比之下，人们对筏内部小叶的脂质组成知之甚少，其中有许多酰化信号转导分子，例如三聚体 G 蛋白和蛋白酪氨酸激酶。 NAP-22 是一种位于筏结构域内叶的神经元蛋白。人们发现这种蛋白质与脂质体中的胆固醇结合。在本研究中，我们使用真核和细菌表达系统进一步分析了 NAP-22 的脂质结合活性。除胆固醇外，NAP-22 在脂质体测定中还显示出磷脂酰乙醇胺 (PE) 和多磷酸肌醇依赖性膜结合。 N 末端肉豆蔻酰化对于脂质体结合至关重要。 C 端删除直至 D61 对结合几乎没有影响。因此，脂质结合区被判断为位于 N 末端 60 个氨基酸序列中。然后在 COS7 细胞中表达 NAP-22，并研究其细胞内定位。生化分析表明 NAP-22 定位于 Triton 不溶性低密度组分中。细胞染色分析显示 NAP-22 与膜中 PE 和胆固醇的共定位模式。 © 2002 Wiley-Liss, Inc.
There exists a microdomain called “raft” in the cell membrane. The enrichment of cholesterol and sphingolipids in its outer leaflet is well recognized. In contrast, little is known of the lipid composition of the inner leaflet of raft, where many acylated signal‐transducing molecules, such as trimeric G proteins and protein tyrosine kinases, associate. NAP‐22 is a neuronal protein localized on the inner leaflet of raft domain. This protein was found to bind cholesterol in the liposome. In this study, we further analyze the lipid binding activity of NAP‐22 using eukaryotic and bacterial expression systems. In addition to cholesterol, NAP‐22 showed a phosphatidylethanolamine (PE)‐ and polyphosphoinositide‐dependent membrane binding in the liposome assay. The N‐terminal myristoylation was essential for the liposome binding. The C‐terminal deletion up to D61 showed little effect on the binding. The lipid binding region was hence judged to be in the N‐terminal 60‐amino‐acid sequence. NAP‐22 was then expressed in COS7 cells, and the intracellular localization was studied. Biochemical analysis showed the localization of NAP‐22 in a Triton‐insoluble low‐density fraction. Cell staining analysis showed colocalization patterns of NAP‐22 with PE and cholesterol in the membrane. © 2002 Wiley‐Liss, Inc.
影响因子：
4.8
作者：
Li, H;Papadopoulos, V
通讯作者：
Papadopoulos, V
影响因子：
4.8
作者：
Li, SW;Couet, J;Lisanti, MP
通讯作者：
Lisanti, MP