Regulation of sorting and post-Golgi trafficking of rhodopsin by its C-terminal sequence QVS(A)PA
Regulation of sorting and post-Golgi trafficking of rhodopsin by its C-terminal sequence QVS(A)PA
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DOI：
10.1073/pnas.95.18.10620
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发表时间：
1998-09-01
影响因子：
11.1
通讯作者：
McDowell, JH
中科院分区：
文献类型：
--
作者：
Deretic, D;Schmerl, S;McDowell, JH
几种导致严重形式的人类疾病常染色体显性视网膜色素变性聚集在视紫红质c端区域的突变。最近的研究表明，视紫红质的c端结构域参与了其通过特殊的高尔基后膜运输到光感受器细胞杆外段的过程。本研究使用合成肽作为青蛙视网膜无细胞系统中视紫红质运输的竞争性抑制剂，描绘了视紫红质C端潜在的调控序列，并模拟了严重色素性视网膜炎等位基因对视紫红质分选的影响。视紫红质c端序列QVS(A)PA在不同物种间高度保守。与牛（氨基酸324-348）和蛙（氨基酸330-354）视紫红质C端对应的多肽分别抑制高尔基后转运50%和60%，并在反式高尔基网络中阻止新合成的视紫红质。与视紫红质细胞质环对应的肽和其他对照肽没有影响。当三种自然发生的突变：Q344ter（缺少最后五个氨基酸QVAPA）， V345M和P347S引入青蛙c端肽时，肽的抑制活性不再检测到。这些观察结果表明，氨基酸QVS(A)PA包含一个信号，可被反式高尔基网络中的特定因子识别。由于后5个氨基酸的突变导致常染色体显性视网膜色素变性，因此缺乏对该序列的识别，很可能导致异常的高尔基后膜形成和视紫红质异常的亚细胞定位。
Several mutations that cause severe forms of the human disease autosomal dominant retinitis pigmentosa cluster in the C-terminal region of rhodopsin. Recent studies have implicated the C-terminal domain of rhodopsin in its trafficking on specialized post-Golgi membranes to the rod outer segment of the photoreceptor cell. Here we used synthetic peptides as competitive inhibitors of rhodopsin trafficking in the frog retinal cell-free system to delineate the potential regulatory sequence within the C terminus of rhodopsin and model the effects of severe retinitis pigmentosa alleles on rhodopsin sorting. The rhodopsin C-terminal sequence QVS(A)PA is highly conserved among different species. Peptides that correspond to the C terminus of bovine (amino acids 324-348) and frog (amino acids 330-354) rhodopsin inhibited post-Golgi trafficking by 50% and 60%, respectively, and arrested newly synthesized rhodopsin in the trans-Golgi network. Peptides corresponding to the cytoplasmic loops of rhodopsin and other control peptides had no effect. When three naturally occurring mutations: Q344ter (lacking the last five amino acids QVAPA), V345M, and P347S were introduced into the frog C-terminal peptide, the inhibitory activity of the peptides was no longer detectable. These observations suggest that the amino acids QVS(A)PA comprise a signal that is recognized by specific factors in the trans-Golgi network. A lack of recognition of this sequence, because of mutations in the last five amino acids causing autosomal dominant retinitis pigmentosa, most likely results in abnormal post-Golgi membrane formation and in an aberrant subcellular localization of rhodopsin.