Cloning and characterization of rat C3a receptor: differential expression of rat C3a and C5a receptors by LPS stimulation

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.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Antigens, CD / chemistry*
  • Antigens, CD / genetics
  • Antigens, CD / physiology
  • Base Sequence
  • Blotting, Northern
  • Blotting, Southern
  • Cloning, Molecular
  • Complement C3a / metabolism
  • Electrophoresis, Agar Gel
  • Gene Expression Regulation / drug effects
  • Gene Expression Regulation / genetics*
  • L Cells
  • Lipopolysaccharides / pharmacology*
  • Membrane Proteins*
  • Mice
  • Molecular Sequence Data
  • Protein Binding
  • RNA, Messenger / analysis
  • Rats
  • Receptor, Anaphylatoxin C5a
  • Receptors, Complement / chemistry*
  • Receptors, Complement / genetics
  • Receptors, Complement / physiology
  • Sequence Analysis, DNA
  • Sequence Homology, Amino Acid
  • Transfection / genetics


  • Antigens, CD
  • Lipopolysaccharides
  • Membrane Proteins
  • RNA, Messenger
  • Receptor, Anaphylatoxin C5a
  • Receptors, Complement
  • complement C3a receptor
  • Complement C3a

Associated data

  • GENBANK/U86379