Distinct protein sorting and localization to premelanosomes, melanosomes, and lysosomes in pigmented melanocytic cells.
Distinct protein sorting and localization to premelanosomes, melanosomes, and lysosomes in pigmented melanocytic cells.
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DOI：
10.1083/jcb.152.4.809
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发表时间：
2001-02-19
期刊：
影响因子：
--
通讯作者：
Marks MS
中科院分区：
文献类型：
--
作者：
Raposo G;Tenza D;Murphy DM;Berson JF;Marks MS
黑素小体和前黑素小体是与溶酶体相关的细胞器，具有独特的结构和一组驻留蛋白。我们已经将这些细胞器定位于色素黑色素瘤细胞和黑素细胞中的内小体和溶酶体。黑素小体驻留蛋白PMel17和TRP1定位于分离不同于富含溶酶体蛋白的囊泡结构。在免疫金标记的超薄冰冻切片中，PMel17沿前黑素小体的管腔内条纹最丰富。伴随着色素沉着增加的是PMel17的减少和界限膜中TRP1的增加。通过液相摄取动力学分析和免疫金标记法，这两种蛋白基本上被排除在富含LAMP1和组织蛋白酶D的溶酶体室外，黑素体前蛋白从一个不寻常的内吞体室内的内吞标记中分离出来。该隔室含有PMel17，15分钟后被BSA-Gold进入，呈酸性，并显示一层含有笼蛋白的细胞质平面涂层。我们的结果表明，前黑素小体和黑素小体代表着不同的细胞器谱系，可与着色细胞中的常规内小体和溶酶体分开。此外，它们还暗示了一个不同寻常的网状蛋白包裹的内体隔室，作为黑素前体和溶酶体的蛋白质被分选的位置。
Melanosomes and premelanosomes are lysosome-related organelles with a unique structure and cohort of resident proteins. We have positioned these organelles relative to endosomes and lysosomes in pigmented melanoma cells and melanocytes. Melanosome resident proteins Pmel17 and TRP1 localized to separate vesicular structures that were distinct from those enriched in lysosomal proteins. In immunogold-labeled ultrathin cryosections, Pmel17 was most enriched along the intralumenal striations of premelanosomes. Increased pigmentation was accompanied by a decrease in Pmel17 and by an increase in TRP1 in the limiting membrane. Both proteins were largely excluded from lysosomal compartments enriched in LAMP1 and cathepsin D. By kinetic analysis of fluid phase uptake and immunogold labeling, premelanosomal proteins segregated from endocytic markers within an unusual endosomal compartment. This compartment contained Pmel17, was accessed by BSA–gold after 15 min, was acidic, and displayed a cytoplasmic planar coat that contained clathrin. Our results indicate that premelanosomes and melanosomes represent a distinct lineage of organelles, separable from conventional endosomes and lysosomes within pigmented cells. Furthermore, they implicate an unusual clathrin-coated endosomal compartment as a site from which proteins destined for premelanosomes and lysosomes are sorted.
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影响因子：
2.3
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影响因子：
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作者：
Heuser, J
通讯作者：
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