Structure and expression of the insulin-like peptide receptor from amphioxus.
Structure and expression of the insulin-like peptide receptor from amphioxus.
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DOI：
10.1210/mend.10.7.8813726
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发表时间：
1996-07
影响因子：
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通讯作者：
Mohammad Pashmforoush;S. J. Chan;D. F. Steiner
中科院分区：
文献类型：
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作者：
Mohammad Pashmforoush;S. J. Chan;D. F. Steiner
胰岛素和胰岛素样生长因子 IGF-1 和 IGF-II 存在于所有脊椎动物中，这些合成代谢肽具有一级和三级结构特征，表明它们是从共同的祖先基因进化而来的。我们提出，最近从原鸡文昌鱼中克隆的胰岛素样肽（ILP）cDNA可能代表了祖先基因，因为ILP的推导序列包含胰岛素和IGF的特征，并且它显然代表了胰岛素/IGF的杂合分子。为了扩展这一假设，我们克隆了编码文昌鱼同源受体的 cDNA。一级序列比较表明，ILP 受体是胰岛素受体家族的成员，在哺乳动物中，该家族包括胰岛素受体 (IR)、I 型 IGF 受体 (IGF-IR) 和 IR 相关受体 (IRR)。在整体氨基酸序列中，ILP受体与人(h)IR有48.6%同一性，与hIGF-IR有47.3%同一性，与hIRR有43.7%同一性，这与hIR和hIGF-IR具有57.6%同一性的发现形成对比。使用简并寡核苷酸引物，我们通过 RT-PCR 显示文昌鱼仅含有胰岛素受体基因家族的单个成员。为了补充序列比较，我们通过将 cDNA 转染至 293 细胞来表达 ILP 受体蛋白。所表达的 ILP 受体的自磷酸化受到浓度约为 5 x 10(-7) M 的合成 ILP 类似物 (B1-Thr)ILP 的半最大刺激。有趣的是，ILP 受体的自磷酸化也可以通过与哺乳动物胰岛素或 IGF-I 一起孵育来刺激，尽管每种都需要同样高的浓度 (10(-5) M)。基于这些结果，我们提出，与ILP基因类似，祖先ILP受体基因在从原索动物到脊椎动物的进化转变过程中也复制并分化产生IR和IGF-IR基因。我们的结果还表明文昌鱼 ILP 受体含有哺乳动物胰岛素和 IGF-I 结合和激活所必需的基本结构决定因素。
Insulin and the insulin-like growth factors IGF-1 and IGF-II are found in all vertebrates, and these anabolic peptides share primary and tertiary structural features which suggest that they have evolved from a common ancestral gene. We have proposed that an insulin-like peptide (ILP) cDNA recently cloned from the protochodate amphioxus may represent the ancestral gene in that the deduced sequence of ILP contains features of both insulin and IGF, and it evidently represents a hybrid insulin/IGF molecule. To expand this hypothesis we have cloned the cDNA that encodes the cognate receptor from amphioxus. Primary sequence comparisons show that the ILP receptor is a member of the insulin receptor family, which in mammals includes the insulin receptor (IR), type I IGF receptor (IGF-IR), and IR-related receptor (IRR). In overall amino acid sequence, the ILP receptor is 48.6% identical to the human (h)IR, 47.3% identical to hIGF-IR, and 43.7% identical to hIRR, and this contrasts with the finding that hIR and hIGF-IR share 57.6% identity. Using degenerate oligonucleotide primers, we show by RT-PCR that amphioxus contains only a single member of the insulin receptor gene family. To complement the sequence comparison, we expressed the ILP receptor protein by transfecting the cDNA into 293 cells. Autophosphorylation of the expressed ILP receptor was half-maximally stimulated by a synthetic ILP analog, (B1-Thr)ILP, at a concentration of about 5 x 10(-7) M. Interestingly, autophosphorylation of the ILP receptor was also stimulated by incubation with either mammalian insulin or IGF-I, although equally high concentrations (10(-5) M) of each were required. Based on these results, we propose that, analogously to the ILP gene, the ancestral ILP receptor gene also duplicated and diverged to generate the IR and IGF-IR genes during the evolutionary transition from protochordates to vertebrates. Our results also indicate that the amphioxus ILP receptor contains the basic structural determinants that are necessary for binding and activation by mammalian insulin and IGF-I.