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The use of membrane translocating peptides to identify sites of interaction between the C5a receptor and downstream effector proteins
Author(s) -
Auger Graham A.,
Smith Brenda M.,
Pease James E.,
Barker Michael D.
Publication year - 2004
Publication title -
immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.297
H-Index - 133
eISSN - 1365-2567
pISSN - 0019-2805
DOI - 10.1111/j.1365-2567.2004.01919.x
Subject(s) - heterotrimeric g protein , c5a receptor , g protein coupled receptor , microbiology and biotechnology , g protein , internalization , receptor , biology , intracellular , g protein coupled receptor kinase , desensitization (medicine) , effector , biochemistry , signal transduction , complement system , immunology , antibody
Summary The complement fragment C5a is a potent leucocyte chemoattractant and activator, mediating its effects through a G‐protein‐coupled receptor. Whilst the C‐terminal domain of this receptor has been shown to be essential for receptor desensitization and internalization, it is not known which domains couple to the receptor's heterotrimeric G proteins. In this report we have used a membrane translocating sequence (MTS) to examine the effects of the four intracellular domains of the human C5a receptor (C5aR) on the receptor's signalling via G αi family heterotrimeric G proteins in intact RBL‐2H3 cells. The results indicate that all of the intracellular domains couple to downstream signalling, with the proximal region of the C terminus being a major binding site and intracellular loop 3 playing a role in G protein activation or receptor desensitization.