Morii H, Watanabe Y
Department of Neuroscience, Osaka Bioscience Institute, Japan.
J Lipid Mediat. 1993 Mar-Apr;6(1-3):445-51.
Prostaglandin (PG) D2 and PGE2 receptor binding activities are regulated in various fashions. The protein phosphorylation by exogenous cAMP-dependent protein kinase or calmodulin-dependent protein kinase II significantly increased PGE2 binding activity through an increase in the apparent amount of the maximal binding, suggesting that the PGE2 receptor may be regulated through protein phosphorylation-dephosphorylation. Other possible regulatory mechanisms were found as the result of studies on functional modification of glycoconjugates. Pretreatment with glycoprotein-specific endoglycosidases (peptide N-glycohydrolase F, endo-alpha-N-acetylgalactosaminidase) decreased both PGD2 and PGE2 receptor binding activities and consequently these activities became nonspecific ones. In addition, these binding activities were increased by the addition of a ganglioside or cerebroside mixture, but not ceramide. The addition of separate purified glycolipids showed more specifically their effect on each PG binding. PGD2 binding activity was increased by GD1a and GQ1b and decreased by GM1 and GT1a, while PGE2 binding activity was increased by GQ1b and galactocerebroside. In such a way, PG receptors may require some specific microenvironment for their maximal binding activity.
前列腺素（PG）D2和PGE2受体结合活性以多种方式受到调节。外源性环磷酸腺苷（cAMP）依赖性蛋白激酶或钙调蛋白依赖性蛋白激酶II介导的蛋白质磷酸化通过增加最大结合的表观量显著提高了PGE2结合活性，这表明PGE2受体可能通过蛋白质磷酸化-去磷酸化进行调节。作为对糖缀合物功能修饰研究的结果，发现了其他可能的调节机制。用糖蛋白特异性内切糖苷酶（肽N-糖苷酶F、内切α-N-乙酰半乳糖胺酶）预处理会降低PGD2和PGE2受体结合活性，结果这些活性变成了非特异性活性。此外，添加神经节苷脂或脑苷脂混合物会增加这些结合活性，但神经酰胺则无此作用。添加单独纯化的糖脂更具体地显示了它们对每种PG结合的影响。GD1a和GQ1b增加PGD2结合活性，GM1和GT1a降低PGD2结合活性，而GQ1b和半乳糖脑苷脂增加PGE2结合活性。通过这种方式，PG受体可能需要一些特定的微环境来实现其最大结合活性。
