G alpha-16 complements the signal transduction cascade of chemotactic receptors for complement factor C5a (C5a-R) and N-formylated peptides (fMLF-R) in Xenopus laevis oocytes: G alpha-16 couples to chemotactic receptors in Xenopus oocytes.
The human leukocyte chemoattractant receptors for complement factor C5a (C5a-R) and N-formylated peptides (fMLF-R) are important members of the superfamily of G-protein coupled receptors (GPCR). Uniquely among the GPCR, these two receptors cannot be expressed in a functionally active form in the oocytes of the frog Xenopus laevis, but require substitution of total RNA of the myelomonocytic U-937 or HL-60 cell lines, respectively. Recently, it was reported that the C5a-R may couple to the alpha subunit of G-16. We have tested this G-protein for its ability to complement the signal transduction cascade of the C5a-R and fMLF-R in Xenopus oocytes. Injection of cRNA for the C5a-R in combination with G alpha-16 led to expression of a functional C5a-R as measured by ligand-induced whole cell current. In contrast to a previous report, the fMLF-R exhibited some residual functional activity when transiently expressed in Xenopus oocytes the extent of which could, however, substantially be increased by coexpression of G alpha-16. Thus, G alpha-16 complements the signal transduction cascade of both receptors in Xenopus laevis oocytes and is most likely the complementing factor present in the U-937 and HL-60 cell lines.
Institute of Medical Microbiology, Hannover Medical School, Germany.
M
M
Burg
U
U
Raffetseder
M
M
Grove
A
A
Klos
J
J
Köhl
W
W
Bautsch
D000818:Animals; D015703:Antigens, CD / Q000378:metabolism*; D015936:Complement C5a / Q000494:pharmacology; D004553:Electric Conductivity; D019204:GTP-Binding Proteins / Q000378:metabolism*; D006801:Humans; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009865:Oocytes; D044087:Receptor, Anaphylatoxin C5a; D011951:Receptors, Complement / Q000378:metabolism*; D044042:Receptors, Formyl Peptide; D011971:Receptors, Immunologic / Q000378:metabolism*; D018000:Receptors, Peptide / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D014981:Xenopus
D015703:Antigens, CD; D044087:Receptor, Anaphylatoxin C5a; D011951:Receptors, Complement; D044042:Receptors, Formyl Peptide; D011971:Receptors, Immunologic; D018000:Receptors, Peptide; D011994:Recombinant Proteins; D009240:N-Formylmethionine Leucyl-Phenylalanine; D015936:Complement C5a; D019204:GTP-Binding Proteins