Alternative splicing of the G protein-coupled receptor superfamily in human airway smooth muscle diversifies the complement of receptors
Alternative splicing of the G protein-coupled receptor superfamily in human airway smooth muscle diversifies the complement of receptors
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DOI：
10.1073/pnas.0801319105
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发表时间：
2008-04-01
影响因子：
11.1
通讯作者：
Liggett, Stephen B.
中科院分区：
文献类型：
--
作者：
Einstein, Richard;Jordan, Heather;Liggett, Stephen B.
G 蛋白偶联受体 (GPCR) 是基因组中最大的信号传导家族，具有广泛的功能，并且是大约 50% 的当前治疗方法的靶点。在许多组织中，例如气道平滑肌（ASM），在没有已知机制的情况下，会对激动剂/拮抗剂产生复杂的、意外的或矛盾的反应。我们假设 ASM 表达的 GPCR 比预期多得多，并且这些 GPCR 经历了大量的选择性剪接，从而创建了高度多样化的受体环境。转录本阵列设计用于检测 434 个 GPCR 及其预测的剪接变体。在这种细胞类型中，检测到 353 个 GPCR（包括 111 个孤儿），表达水平相差约 900 倍。用于治疗气道疾病的受体的表达低于具有类似信号特性的其他受体，这表明潜在的更有效的靶标。发现了不成比例的 A 类肽基受体以及与 G(q/11) 或 G(s)（相对于 G(j)）偶联的受体。重要的是，由于剪接事件，192个GPCR平均有五种不同表达的受体亚型，包括可变剪接供体和受体、新内含子、内含子保留、外显子跳跃和新外显子，其中后两种事件最为普遍。利用白三烯 B4 受体进一步研究了剪接的后果，白三烯 B4 受体因其在肺部的异常反应而闻名。由于供体和受体剪接位点的替代，我们发现了三种变体的转录表达，代表了 38 和 100 个氨基酸的框内删除，并且所有三种亚型的蛋白质表达。因此，受条件、时间和细胞类型调控的选择性剪接是使 GPCR 超家族多样化的主要机制，创造具有特殊环境的局部受体组。
G protein-coupled receptors (GPCRs) are the largest signaling family in the genome, serve an expansive array of functions, and are targets for approximate to 50% of current therapeutics. In many tissues, such as airway smooth muscle (ASM), complex, unexpected, or paradoxical responses to agonists/antagonists occur without known mechanisms. We hypothesized that ASM express many more GPCRs than predicted, and that these undergo substantial alternative splicing, creating a highly diversified receptor milieu. Transcript arrays were designed detecting 434 GPCRs and their predicted splice variants. in this cell type, 353 GPCRs were detected (including 111 orphans), with expression levels varying by approximate to 900-fold. Receptors used for treating airway disease were expressed lower than others with similar signaling properties, indicating potentially more effective targets. A disproportionate number of Class-A peptide-group receptors, and those coupling to G(q/11) or G(s) (vs. G(j)), was found. Importantly, 192 GPCRs had, on average, five different expressed receptor isoforms because of splicing events, including alternative splice donors and acceptors, novel introns, intron retentions, exon(s) skips, and novel exons, with the latter two events being most prevalent. The consequences of splicing were further investigated with the leukotriene B4 receptor, known for its aberrant responsiveness in lung. We found transcript expression of three variants because of alternative donor and acceptor splice sites, representing in-frame deletions of 38 and 100 aa, with protein expression of all three isoforms. Thus, alternative splicing, subject to conditional, temporal, and cell-type regulation, is a major mechanism that diversifies the GPCR superfamily, creating local recepteromes with specialized environments.