Identification of a lipase-linked cell membrane receptor for pigment epithelium-derived factor
Identification of a lipase-linked cell membrane receptor for pigment epithelium-derived factor
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DOI：
10.1074/jbc.m600353200
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发表时间：
2006-12-08
影响因子：
4.8
通讯作者：
Becerra, S. Patricia
中科院分区：
文献类型：
--
作者：
Notari, Luigi;Baladron, Victoriano;Becerra, S. Patricia
色素上皮衍生因子（PEDF）是一种细胞外多功能蛋白，属于蛇形蛋白超家族，具有明显的神经营养、胶质细胞、神经营养、抗血管生成和抗肿瘤特性。我们已经在视网膜、视网膜母细胞瘤和中枢神经系统细胞的质膜中提供了高亲和力pedf结合位点和蛋白的生化证据。本研究旨在揭示参与PEDF生物活性的受体。利用酵母双杂交筛选，我们从人类视网膜色素上皮中鉴定出一个新的基因，该基因编码pedf结合伴侣，我们称之为PEDF-R。衍生多肽假定具有跨膜、细胞内和细胞外区域以及磷脂酶结构域。最近，在脂肪细胞中发现了PEDF-R (TTS2.2/独立磷脂酶A(2) (PLA(2))zeta和小鼠去营养蛋白/ATGL)，它们是具有甘油三酯脂肪酶和酰基甘油转酰基酶活性的新的不依赖钙的PLA(2)/营养蛋白/patatin样磷脂酶结构域2 （PNPLA2）家族的成员。在这里，我们描述了PEDF- r基因在视网膜中的表达及其在细菌和真核系统中的异源表达，我们证明了其蛋白产物对PEDF具有特异性和高结合亲和力，具有有效的磷脂酶a(2)活性，可以释放脂肪酸，并且与真核细胞膜有关。最重要的是，PEDF结合刺激PEDF- r的酶促磷脂酶A(2)活性。总之，我们在视网膜中发现了一个新的PEDF- r基因，该基因与PEDF具有高亲和力的磷脂酶连接膜蛋白有关，这表明配体/受体在细胞表面相互作用可以产生细胞信号的分子途径。
Pigment epithelium-derived factor (PEDF) is an extracellular multifunctional protein belonging to the serpin superfamily with demonstrable neurotrophic, gliastatic, neuronotrophic, antiangiogenic, and antitumorigenic properties. We have previously provided biochemical evidence for high affinity PEDF-binding sites and proteins in plasma membranes of retina, retinoblastoma, and CNS cells. This study was designed to reveal a receptor involved in the biological activities of PEDF. Using a yeast two-hybrid screening, we identified a novel gene from pigment epithelium of the human retina that codes for a PEDF-binding partner, which we term PEDF-R. The derived polypeptide has putative transmembrane, intracellular and extracellular regions, and a phospholipase domain. Recently, PEDF-R (TTS2.2/independent phospholipase A(2) (PLA(2))zeta and mouse desnutrin/ATGL) has been described in adipose cells as a member of the new calcium-independent PLA(2)/nutrin/patatin- like phospholipase domain-containing 2 (PNPLA2) family that possesses triglyceride lipase and acylglycerol transacylase activities. Here we describe the PEDF-R gene expression in the retina and its heterologous expression by bacterial and eukaryotic systems, and we demonstrate that its protein product has specific and high binding affinity for PEDF, has a potent phospholipase A(2) activity that liberates fatty acids, and is associated with eukaryotic cell membranes. Most importantly, PEDF binding stimulates the enzymatic phospholipase A(2) activity of PEDF-R. In conclusion, we have identified a novel PEDF-R gene in the retina for a phospholipase-linked membrane protein with high affinity for PEDF, suggesting a molecular pathway by which ligand/receptor interaction on the cell surface could generate a cellular signal.