Structures and functions of the Prostanoid Receptors

1.利用先前克隆的血栓素（TX）受体（TP）和前列腺素（PG） E受体EP3亚型（EP3）的cdna和核苷酸序列，克隆了不同物种6种类型和亚型的前列腺素受体的cdna。它们包括PGD受体（DP）、PGE受体EP1、EP2和EP4亚型、PGF受体（FP）和PGI受体（IP）。研究了它们的结构、配体结合特异性和信号转导途径。确定了这些受体基因在小鼠染色体上的遗传位点，并阐明了人类TP和IP的基因结构。发现了选择性剪接产生的EP3和TP受体同工型。它们仅在c端尾部存在差异，但在信号转导途径上存在差异。通过northern blot分析揭示了这些受体在体内的分布，并通过原位杂交对小鼠的IP、小鼠脑内的EP3和小鼠肾内的PGE受体亚型进行了详细分析。测定TP在小鼠胸腺和肝脏中的特异性功能，以及EP2和EP3在小鼠脑中的特异性功能。在遗传性出血性疾病患者中发现TP点突变，并确定为该疾病的原因。本研究明确了所有8种前列腺素受体的分子结构，为前列腺素分子的多种生理作用提供了分子基础。

1.cDMAs for six types and subtypes of the prostanoid receptors of various species were cloned by the use of the cDNAs and nucleotide sequences of the thromboxane (TX) receptor (TP) and the prostaglandin (PG) E receptor EP3 subtype (EP3) we previously cloned. They include PGD receptor (DP) , PGE receptor EP1, EP2 and EP4 subtypes, PGF receptor (FP) and PGI receptor (IP) . Their structures, ligand binding specificities and signal transduction pathways were characterized.2.Genetic loci of these receptor genes on mouse chromosomes were determined, and gene structures of the human TP and IP were elucidated.3.The receptor isoforms of EP3 and TP created by altemative splicing were found. They were different only in the C-terminal tail but different in the signal transduction pathways.4.Distribution of these receptors in the body was revealed by northem blot analysis, and the detailed analysis by in situ hybridization were carried out for IP in mouse, for EP3 in mouse brain and for PGE receptor subtypes in mouse kidney. Specific functions were examined for TP in mouse thymus and in liver, and EP2 and EP3 in mouse brain.5.A point mutation was found in TP in patients with inherited bleeding disorder and identified as a cause of this disease.This work has thus clucidated molecular structures of all of the eight prostanoid receptors and provided the molecular basis for diverse physiological actions of the prostanoid molecules.