Non-homologous sequences of parathyroid hormone and the parathyroid hormone related peptide bind to a common receptor on ROS 17/2.8 cells.
Non-homologous sequences of parathyroid hormone and the parathyroid hormone related peptide bind to a common receptor on ROS 17/2.8 cells.
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甲状旁腺激素和甲状旁腺激素相关肽的非同源序列与 ROS 17/2.8 细胞上的共同受体结合。
DOI：
10.1210/endo-125-4-2215
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发表时间：
1989
期刊：
影响因子：
4.8
通讯作者：
S. Nussbaum
中科院分区：
文献类型：
--
作者：
A. Abou;S. Uneno;H. Jueppner;H. Keutmann;J. Potts;G. Segre;S. Nussbaum
我们和其他人最近发现，甲状旁腺激素(PTH)和甲状旁腺激素相关肽(PTHrP)的氨基末端序列在前13个残基中有62%的同源性，与ROS17/2.8细胞上的同一受体结合。其余的PTHrP序列与PTH明显不同，提示受体结合可能依赖于这两个肽的前13个氨基酸。然而，由于氨基酸残基14-34被认为是甲状旁腺素的重要结合域，这两个肽在这一部分二级结构中的构象相似性可能有助于它们与同一受体结合的能力。为了验证这一假设，我们合成了[Tyr36，Cys38]PTHrP-(14-38)和[Tyr34]bpth(14-34)NH2，并研究了这两个肽与ROS17/2.8细胞上共同的PTH/PTHrP受体的结合。用放射性碘标记的[Nle8，18，Tyr34]bpth(1-34)NH2(NlePTH)和[Tyr36]PTHrP-(1-36)NH2从功能上定义受体结合要求。[Tyr36，Cys38]PTHrP(14-38)和[Tyr34]bpth(14-34)NH2与125I-NlePTH竞争ROS 17/2.8细胞的结合部位，表观KDS分别为10微米和50微米。这两个多肽还与125I-[Tyr36]PTHrP(1-36)NH2竞争，表观KDS分别为30微米和10微米。在相同的测定体系中，NlePTH和[Tyr36，Cys38]PTHrP(1-38)抑制任何一种放射性碘配体的结合，表观KDS分别为0.3和1.0 nM。这些研究表明，尽管[Tyr34]bpth(14-34)NH2和[Tyr36，Cys38]PTHrP(14-38)几乎没有序列同源性，但它们的二级结构必须足够相似，才能与共同的PTH/PTHrP受体结合。
We and others have recently shown that amino terminal sequences of parathyroid hormone (PTH) and parathyroid hormone related peptide (PTHrP), which share a 62% homology within the first 13 residues, bind to the same receptor on ROS 17/2.8 cells. The remaining PTHrP sequence is markedly different from PTH, suggesting that receptor binding may be dependent on the first 13 amino acids of either peptide. However, since the amino acid residues 14-34 have previously been recognized as an important binding domain for PTH, conformational similarity within this portion's secondary structure of both peptides could contribute to their capacity to bind to the same receptor. To test this hypothesis, we synthesized [Tyr36,Cys38]PTHrP-(14-38) and [Tyr34]bPTH(14-34)NH2, and studied binding of both peptides to the common PTH/PTHrP receptor on ROS 17/2.8 cells. Radioiodinated, HPLC-purified [Nle8,18, Tyr34]bPTH(1-34)NH2 (NlePTH) and [Tyr36]PTHrP-(1-36)NH2 were used to functionally define receptor binding requirements. [Tyr36,Cys38]PTHrP(14-38) and [Tyr34]bPTH(14-34)NH2 competed with 125I-NlePTH for binding sites on ROS 17/2.8 cells with apparent Kds of 10 microM and 50 microM respectively. Both peptides also competed with 125I-[Tyr36]PTHrP(1-36)NH2 with apparent Kds of 30 microM and 10 microM respectively. In the same assay system, NlePTH and [Tyr36,Cys38]PTHrP(1-38)inhibited binding of either radioiodinated ligand with apparent Kds of 0.3 and 1.0 nM. These studies indicate that although [Tyr34]bPTH(14-34)NH2 and [Tyr36,Cys38]PTHrP(14-38) share virtually no sequence homology, their secondary structures must be sufficiently similar to permit binding to a common PTH/PTHrP receptor.