Nakamura M, Honda Z, Matsumoto T, Noma M, Shimizu T
Department of Biochemistry, Faculty of Medicine, University of Tokyo, Japan.
J Lipid Mediat. 1993 Mar-Apr;6(1-3):163-8.
The cDNA encoding the platelet-activating factor (PAF) receptor was cloned from a guinea pig lung cDNA library by using a Xenopus laevis oocyte expression system. The human PAF receptor cDNA was isolated from a human leukocyte cDNA library using a 0.8-kbp fragment of the guinea pig PAF receptor cDNA as a probe. Both receptors have the same number of amino acids (342 residues) with seven putative transmembrane spanning domains, and belong to the G-protein-linked receptor superfamily. Overall amino acid identity between the two receptors was 83%:91% in the transmembrane domains. Seven threonine and three serine residues conserved in the cytoplasmic loops of both receptors may function as phosphate acceptors, as related to the homologous desensitization of the receptor. Activation of the PAF receptor yielded inositol 1,4,5-trisphosphate production in the PAF receptor expressed COS-7 cells and oocytes, and guanosine 5'-O-(2-thio)bisphosphate injected into the oocytes inhibited PAF-induced Cl- current, providing evidence that PAF stimulates phosphoinositide turnover via G-protein(s).
通过使用非洲爪蟾卵母细胞表达系统，从豚鼠肺cDNA文库中克隆出编码血小板活化因子（PAF）受体的cDNA。以豚鼠PAF受体cDNA的0.8kb片段为探针，从人白细胞cDNA文库中分离出人PAF受体cDNA。两种受体具有相同数量的氨基酸（342个残基），有七个推定的跨膜结构域，属于G蛋白偶联受体超家族。两种受体之间的总体氨基酸同一性为83%：跨膜结构域中为91%。两种受体胞质环中保守的七个苏氨酸和三个丝氨酸残基可能作为磷酸受体，与受体的同源脱敏有关。PAF受体的激活在表达PAF受体的COS-7细胞和卵母细胞中产生肌醇1,4,5-三磷酸，注入卵母细胞的鸟苷5'-O-(2-硫代)二磷酸抑制PAF诱导的Cl-电流，这证明PAF通过G蛋白刺激磷酸肌醇代谢。
