Niemann-Pick C1 protein: obligatory roles for N-terminal domains and lysosomal targeting in cholesterol mobilization.
Niemann-Pick C1 protein: obligatory roles for N-terminal domains and lysosomal targeting in cholesterol mobilization.
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DOI：
10.1073/pnas.96.3.805
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发表时间：
1999-02
影响因子：
11.1
通讯作者：
H. Watari;E. Blanchette‐Mackie;N. Dwyer;J. M. Glick;Shutish C. Patel;E. Neufeld;R. Brady;P. Pentchev;J. Strauss
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文献类型：
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作者：
H. Watari;E. Blanchette‐Mackie;N. Dwyer;J. M. Glick;Shutish C. Patel;E. Neufeld;R. Brady;P. Pentchev;J. Strauss
C型尼曼-匹克病（NPC）是一种遗传性脂质储存障碍，影响内脏和中枢神经系统。NPC细胞的特征性特征是低密度脂蛋白衍生的胆固醇的溶酶体积累。为了阐明最近发现的NPC 1基因产物在NPC疾病中的缺陷的重要结构特征，我们研究了野生型NPC 1和NPC 1突变体在显示NPC胆固醇运输缺陷的模型细胞系（CT60中国仓鼠卵巢细胞）中纠正低密度脂蛋白衍生胆固醇的过度溶酶体储存的能力。用人野生型NPC 1转染的CT60细胞含有定位于溶酶体/内体区室的170和190 kDa的免疫反应性蛋白。野生型NPC 1蛋白纠正了CT 60细胞中NPC胆固醇运输缺陷。NPC 1 N末端保守的半胱氨酸残基突变为丝氨酸残基导致蛋白质靶向溶酶体膜环绕胆固醇负载的核心，而缺失含有LLNF溶酶体靶向基序的C-末端4-aa残基导致蛋白质表达定位于内质网。这些突变NPC 1蛋白都没有纠正CT 60细胞中NPC胆固醇运输缺陷。我们的结论是，运输的NPC 1蛋白的胆固醇负载的溶酶体室是必不可少的表达其生物活性和结构域的NPC 1蛋白的N末端是关键的动员胆固醇从溶酶体。
Niemann-Pick type C (NPC) disease is an inherited lipid storage disorder that affects the viscera and central nervous system. A characteristic feature of NPC cells is the lysosomal accumulation of low density lipoprotein-derived cholesterol. To elucidate important structural features of the recently identified NPC1 gene product defective in NPC disease, we examined the ability of wild-type NPC1 and NPC1 mutants to correct the excessive lysosomal storage of low density lipoprotein-derived cholesterol in a model cell line displaying the NPC cholesterol-trafficking defect (CT60 Chinese hamster ovary cells). CT60 cells transfected with human wild-type NPC1 contained immunoreactive proteins of 170 and 190 kDa localized to the lysosomal/endosomal compartment. Wild-type NPC1 protein corrected the NPC cholesterol-trafficking defect in the CT60 cells. Mutation of conserved cysteine residues in the NPC1 N terminus to serine residues resulted in proteins targeted to lysosomal membranes encircling cholesterol-laden cores, whereas deletion of the C-terminal 4-aa residues containing the LLNF lysosome-targeting motif resulted in the expression of protein localized to the endoplasmic reticulum. None of these mutant NPC1 proteins corrected the NPC cholesterol-trafficking defect in CT60 cells. We conclude that transport of the NPC1 protein to the cholesterol-laden lysosomal compartment is essential for expression of its biological activity and that domains in the N terminus of the NPC1 protein are critical for mobilization of cholesterol from lysosomes.