Gehlert D R, Schober D A, Beavers L, Gadski R, Hoffman J A, Smiley D L, Chance R E, Lundell I, Larhammar D
Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana 46285, USA.
Mol Pharmacol. 1996 Jul;50(1):112-8.
Traditionally, neuropeptide Y (NPY) receptors have been divided into Y1 and Y2 subtypes based on peptide pharmacology and synaptic localization. Other receptor subtypes have been proposed based on preferences for NPY, peptide YY (PYY), or pancreatic polypeptide (PP). Recently, we discovered a novel human member of this receptor family exhibiting high affinity for PP and PYY. In the current study, we expressed a DNA clone encoding this human PP-preferring receptor [hPP1 (or Y4)] in Chinese hamster ovary cells and performed a peptide structure-activity study. [125I]pPYY bound to homogenates of hPP1-Chinese hamster ovary cells with a Kd of 0.064 +/- 0.006 nM and a Bmax of 244 +/- 12 fmol/mg protein. Human PP inhibited binding with a Ki of 0.023 nM, whereas human PYY (Ki = 0.31 nM) and human NPY Ki = 12 nM) were significantly less potent. Rat, porcine, and bovine PP inhibited binding with similar affinities to human PP, whereas avian PP was substantially less potent (Ki = 1 nM). Deletion of the first four amino acids reduced the affinity of bovine PP to 1 nM. Carboxyl-terminal fragments of NPY and PYY also had reduced potency compared with the native peptides. In addition, deletion of Tyr36-amide produced a substantial reduction in affinity. Pro34-substituted NPY and PYY had modestly increased affinity compared with the native peptides, although Gln34-bPP had similar affinity compared with bovine PP. The carboxyl-terminally derived Y1 antagonist 1229U91 was a very potent (Ki = 0.042 nM) inhibitor of binding to hPP1. Thus, the carboxyl-terminal region of PP seems to be the most important part of the peptide for high affinity binding to hPP1. A few key residues (amino acids 2 and 3) in the amino-terminal region of PP contribute to the high affinity of the native peptide. Thus, features required for peptide recognition by the hPP1 receptor seem to be distinct from the Y1 and Y2 receptor.
传统上，基于肽药理学和突触定位，神经肽Y（NPY）受体已被分为Y1和Y2亚型。基于对NPY、肽YY（PYY）或胰多肽（PP）的偏好，还提出了其他受体亚型。最近，我们发现了该受体家族的一个新的人类成员，它对PP和PYY表现出高亲和力。在当前研究中，我们在中国仓鼠卵巢细胞中表达了编码这种人类PP偏好受体[hPP1（或Y4）]的DNA克隆，并进行了肽结构-活性研究。[125I]pPYY与hPP1-中国仓鼠卵巢细胞匀浆结合，Kd为0.064±0.006 nM，Bmax为244±12 fmol/mg蛋白质。人PP抑制结合的Ki为0.023 nM，而人PYY（Ki = 0.31 nM）和人NPY（Ki = 12 nM）的效力明显较低。大鼠、猪和牛的PP以与人PP相似的亲和力抑制结合，而禽PP的效力则低得多（Ki = 1 nM）。缺失前四个氨基酸会使牛PP的亲和力降至1 nM。与天然肽相比，NPY和PYY的羧基末端片段的效力也有所降低。此外，缺失Tyr36-酰胺会导致亲和力大幅降低。与天然肽相比，Pro34取代的NPY和PYY的亲和力略有增加，尽管Gln34-bPP与牛PP的亲和力相似。羧基末端衍生的Y1拮抗剂1229U91是与hPP1结合的非常有效的（Ki = 0.042 nM）抑制剂。因此，PP的羧基末端区域似乎是肽与hPP1高亲和力结合的最重要部分。PP氨基末端区域的一些关键残基（第2和3位氨基酸）有助于天然肽的高亲和力。因此，hPP1受体识别肽所需的特征似乎与Y1和Y2受体不同。
