Analysis of the linkage of MYRIP and MYO7A to melanosomes by RAB27A in retinal pigment epithelial cells
Analysis of the linkage of MYRIP and MYO7A to melanosomes by RAB27A in retinal pigment epithelial cells
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DOI：
10.1002/cm.20198
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发表时间：
2007-06-01
影响因子：
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通讯作者：
Williams, David S.
中科院分区：
文献类型：
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作者：
Klomp, Adriana E.;Teofilo, Karen;Williams, David S.
视网膜色素上皮（RPE）的顶端区域通常含有黑素体。它们的顶端分布依赖于RAB 27 A和非常规肌球蛋白MYO 7A。来自使用体外结合测定、黑素细胞转染和免疫定位的研究的证据表明，亲外素MYRIP将黑素体上的RAB 27 A连接到MYO 7A，类似于亲黑素将黑素细胞黑素体上的RAB 27 A连接到MYO 5A的方式。为了测试这一假设在RPE细胞中的功能，我们通过原代培养的RPE细胞的研究（包括活细胞成像）、突变小鼠视网膜的分析和RPE细胞分级分离实验，检查了MYRIP、RAB 27 A和MYO 7A之间的关系。我们的研究结果表明，视网膜分布的MYRIP是有限的RPE，主要是顶端区域。在RPE细胞中，RAB 27 A、MYRIP和MYO 7A都与黑素体相关，经历缓慢和快速的运动。对突变小鼠的分析提供了MYRIP通过RAB 27 A与黑素体相关的遗传证据，但显示MYRIP向顶端RPE的募集独立于黑素体和RAB 27 A。RAB 27 A和MYRIP也与来源不明的能动小泡有关。目前的结果提供了来自活RPE细胞的证据，证明RAB 27 A-MYRIP-MYO 7A复合物在黑素体运动中起作用。他们还证明了RAB 27 A提供了与黑素体的重要联系。细胞动力。Cytoskeleton 64：474-487，2007. (C)2007 Wiley-Liss，Inc.
The apical region of the retinal pigment epithelium (RPE) typically contains melanosomes. Their apical distribution is dependent on RAB27A and the unconventional myosin, MYO7A. Evidence from studies using in vitro binding assays, melanocyte transfection, and immunolocalization have indicated that the exophilin, MYRIP, links RAB27A on melanosomes to MYO7A, analogous to the manner that melanophilin links RAB27A on melanocyte melanosomes to MYO5A. To test the functionality of this hypothesis in RPE cells, we have examined the relationship among MYRIP, RAB27A and MYO7A with studies of RPE cells in primary culture (including live-cell imaging), analyses of mutant mouse retinas, and RPE cell fractionation experiments. Our results indicate that the retinal distribution of MYRIP is limited to the RPE, mainly the apical region. In RPE cells, RAB27A, MYRIP, and MYO7A were all associated with melanosomes, undergoing both slow and rapid movements. Analyses of mutant mice provide genetic evidence that MYRIP is linked to melanosomes via RAB27A, but show that recruitment of MYRIP to apical RPE is independent of melanosomes and RAB27A. RAB27A and MYRIP also associated with motile small vesicles of unknown origin. The present results provide evidence from live RPE cells that the RAB27A-MYRIP-MYO7A complex functions in melanosome motility. They also demonstrate that RAB27A provides an essential link to the melanosome. Cell Motil. Cytoskeleton 64:474-487, 2007. (C) 2007 Wiley-Liss, Inc.