Molecular characterization of caveolin association with the Golgi complex: identification of a cis-Golgi targeting domain in the caveolin molecule.
Molecular characterization of caveolin association with the Golgi complex: identification of a cis-Golgi targeting domain in the caveolin molecule.
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DOI：
10.1083/jcb.145.7.1443
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发表时间：
1999-06-28
期刊：
影响因子：
--
通讯作者：
Parton RG
中科院分区：
文献类型：
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作者：
Luetterforst R;Stang E;Zorzi N;Carozzi A;Way M;Parton RG
小窝蛋白是一种完整的膜蛋白，是小窝的主要成分。此外，小窝蛋白已被提出在细胞内隔室和细胞表面之间循环，但小窝蛋白分子中确切的运输路线和靶向信息尚未定义。我们发现，针对小窝蛋白支架结构域或针对小窝蛋白-1的COOH端的抗体对小窝蛋白高尔基体池显示出显著的特异性，并且不能通过免疫荧光识别表面小窝蛋白。为了更详细地分析小窝蛋白高尔基体的靶向性，我们在成纤维细胞中表达了小窝蛋白突变体。缺乏NH2末端的特定突变体被定位于顺式高尔基体，但在表面小凹中检测不到。此外，小窝蛋白-3的COOH末端胞质结构域的一个32个氨基酸片段被特异性地和专一性地靶向高尔基复合体，并且可以靶向这个隔室的可溶性异源蛋白-绿色荧光蛋白。棕榈酰化缺陷的COOH末端突变体与高尔基复合体的关联可以忽略不计。这项研究定义了小窝蛋白分子中独特的高尔基体靶向信息，并确定顺式高尔基体复合体是小窝蛋白循环途径上的中间隔室。
Caveolins are integral membrane proteins which are a major component of caveolae. In addition, caveolins have been proposed to cycle between intracellular compartments and the cell surface but the exact trafficking route and targeting information in the caveolin molecule have not been defined. We show that antibodies against the caveolin scaffolding domain or against the COOH terminus of caveolin-1 show a striking specificity for the Golgi pool of caveolin and do not recognize surface caveolin by immunofluorescence. To analyze the Golgi targeting of caveolin in more detail, caveolin mutants were expressed in fibroblasts. Specific mutants lacking the NH2 terminus were targeted to the cis Golgi but were not detectable in surface caveolae. Moreover, a 32–amino acid segment of the putative COOH-terminal cytoplasmic domain of caveolin-3 was targeted specifically and exclusively to the Golgi complex and could target a soluble heterologous protein, green fluorescent protein, to this compartment. Palmitoylation-deficient COOH-terminal mutants showed negligible association with the Golgi complex. This study defines unique Golgi targeting information in the caveolin molecule and identifies the cis Golgi complex as an intermediate compartment on the caveolin cycling pathway.