Fukuoka Y, Ember J A, Hugli T E
Department of Immunology, Scripps Research Institute, La Jolla, California 92037, USA.
Biochem Biophys Res Commun. 1998 Jan 26;242(3):663-8. doi: 10.1006/bbrc.1997.8034.
The anaphylatoxin C3a, generated during complement activation, is a factor known to mediate various inflammatory reactions. The human C3a receptor (C3aR) was recently cloned and identified to be a member of the G-protein-coupled receptor family. C3aR is characterized by seven transmembrane domains including a large second extracellular loop that appears to be a unique feature of this receptor. Here we report the isolation of the rat C3aR clone and confirm that the isolated cDNA coded for rat C3aR based on C3a binding analysis to stably transfected cells. Northern blot analysis of rat C3aR revealed expression in various tissues, similar to that of human C3aR but dissimilar to rat C5aR. We found that expression of rat C3aR in various tissues did not increase significantly after LPS injection, whereas rat C5aR expression is greatly increased. These results suggest that expression of C3aR and C5aR is independently regulated in rat cells and tissues.
过敏毒素C3a在补体激活过程中产生，是一种已知可介导多种炎症反应的因子。人C3a受体（C3aR）最近被克隆并鉴定为G蛋白偶联受体家族的成员。C3aR的特征是具有七个跨膜结构域，包括一个大的第二细胞外环，这似乎是该受体的独特特征。在此，我们报告大鼠C3aR克隆的分离，并基于对稳定转染细胞的C3a结合分析，证实分离的cDNA编码大鼠C3aR。大鼠C3aR的Northern印迹分析显示其在各种组织中表达，与人C3aR相似，但与大鼠C5aR不同。我们发现，LPS注射后，大鼠C3aR在各种组织中的表达没有显著增加，而大鼠C5aR的表达则大幅增加。这些结果表明，大鼠细胞和组织中C3aR和C5aR的表达是独立调节的。
