Intracellular dynamics of sst5 receptors in transfected COS-7 cells: maintenance of cell surface receptors during ligand-induced endocytosis.
Intracellular dynamics of sst5 receptors in transfected COS-7 cells: maintenance of cell surface receptors during ligand-induced endocytosis.
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转染 COS-7 细胞中 sst5 受体的细胞内动力学：配体诱导的内吞作用期间细胞表面受体的维持。
作者：
T. Stroh;A.C. Jackson;Philippe Sarret;C. D. Farra;Jean;H. Kreienkamp;J. Mazella;Alain Beaudet
G蛋白偶联受体的内化对于磷酸化脱敏受体的再敏化至关重要，而且对于它们通过螯合的长期脱敏也至关重要。为了阐明生长抑素（SRIF）受体亚型SST 5的细胞表面可用性的调节机制，我们采用生化，共聚焦显微镜和电子显微镜技术，其特点是在转染COS-7细胞的内化特性。我们的研究结果表明，特异性结合的[125 I] Tyr 0-D-Trp 8-SRIF（高达45%的结合放射性）的快速和有效的螯合。结合免疫细胞化学检测的SST 5和可视化的荧光SRIF类似物的共聚焦显微镜显示，而内化的配体逐渐聚集向细胞中心随着时间的推移，免疫反应性受体仍然主要与质膜。通过对全细胞的结合实验证实了细胞表面受体的保存，揭示了在37 ℃下[125 I] Tyr 0-D-Trp 8-SRIF结合的饱和性的缺乏。药物莫能菌素使结合变得饱和，表明受体再循环在细胞表面受体的保存中起着关键作用。电子显微镜显示，除了受体再循环，受体-配体复合物的内化引发了大量的sst 5受体分子从细胞内储存到细胞膜。备用受体的再循环和募集的这种组合可以通过隔离保护sst 5免受长期下调，因此促进延长的SRIF信号传导。
Internalization of G protein-coupled receptors is crucial for resensitization of phosphorylation-desensitized receptors, but also for their long term desensitization through sequestration. To elucidate the mechanisms regulating cell surface availability of the somatostatin (SRIF) receptor subtype sst5, we characterized its internalization properties in transfected COS-7 cells using biochemical, confocal microscopic, and electron microscopic techniques. Our results demonstrated rapid and efficient sequestration of specifically bound [125I]Tyr0-D-Trp8-SRIF (up to 45% of bound radioactivity). Combined immunocytochemical detection of sst5 and visualization of a fluorescent SRIF analog by confocal microscopy revealed that whereas the internalized ligand progressively clustered toward the cell center with time, immunoreactive receptors remained predominantly associated with the plasma membrane. The preservation of cell surface receptors was confirmed by binding experiments on whole cells revealing a lack of saturability of [125I]Tyr0-D-Trp8-SRIF binding at 37 C. Binding was rendered saturable by the drug monensin, showing that receptor recycling played a key role in the preservation of cell surface receptors. Electron microscopy demonstrated that in addition to receptor recycling, internalization of receptor-ligand complexes triggered a massive recruitment of sst5 receptor molecules from intracellular stores to the membrane. This combination of recycling and recruitment of spare receptors may protect sst5 from long term down-regulation through sequestration and, therefore, facilitate extended SRIF signaling.
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DOI：
--
发表时间：
1995-08
期刊：
Comptes rendus de l'Academie des sciences. Serie III, Sciences de la vie
影响因子：
--
作者：
C. Viollet;A. Faivre‐Bauman;Ji Zhang;C. Llorens-Cortes;C. Loudes;C. Kordon;J. Epelbaum
通讯作者：
C. Viollet;A. Faivre‐Bauman;Ji Zhang;C. Llorens-Cortes;C. Loudes;C. Kordon;J. Epelbaum
DOI：
--
发表时间：
1992-10
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
K. Yasuda;S. Rens‐Domiano;C. Breder;S. Law;C. Saper;T. Reisine;G. Bell
通讯作者：
K. Yasuda;S. Rens‐Domiano;C. Breder;S. Law;C. Saper;T. Reisine;G. Bell
影响因子：
3.3
作者：
GRADY, EF;GARLAND, AM;BUNNETT, NW
通讯作者：
BUNNETT, NW
脑室内注射生长抑素sst5受体激动剂抑制大鼠胃酸分泌。
DOI：
10.1016/0014-2999(95)00690-7
发表时间：
1996
期刊：
European journal of pharmacology.
影响因子：
--
作者：
Martinez,V;Coy,DH;Lloyd,KC;Tache,Y
通讯作者：
Tache,Y
克隆的生长抑素受体 SSTR4 和 SSTR5 的表征。
影响因子：
3.6
作者：
Raynor,K;O'Carroll,AM;Kong,H;Yasuda,K;Mahan,LC;Bell,GI;Reisine,T
通讯作者：
Reisine,T