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

FEBS Lett. 1995 Dec 27;377(3):426-8. doi: 10.1016/0014-5793(95)01379-2.

Abstract

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.

MeSH terms

  • Animals
  • Antigens, CD / metabolism*
  • Complement C5a / pharmacology
  • Electric Conductivity
  • GTP-Binding Proteins / metabolism*
  • Humans
  • N-Formylmethionine Leucyl-Phenylalanine / pharmacology
  • Oocytes
  • Receptor, Anaphylatoxin C5a
  • Receptors, Complement / metabolism*
  • Receptors, Formyl Peptide
  • Receptors, Immunologic / metabolism*
  • Receptors, Peptide / metabolism*
  • Recombinant Proteins / metabolism
  • Signal Transduction / physiology*
  • Xenopus

Substances

  • Antigens, CD
  • Receptor, Anaphylatoxin C5a
  • Receptors, Complement
  • Receptors, Formyl Peptide
  • Receptors, Immunologic
  • Receptors, Peptide
  • Recombinant Proteins
  • N-Formylmethionine Leucyl-Phenylalanine
  • Complement C5a
  • GTP-Binding Proteins