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Thrombin primes responsiveness of selective chemoattractant receptors at a site distal to G protein activation.

Publication ,  Journal Article
Ali, H; Tomhave, ED; Richardson, RM; Haribabu, B; Snyderman, R
Published in: J Biol Chem
February 9, 1996

To define the molecular basis of human chemoattractant receptor regulation, rat basophilic leukemia RBL-2H3 cells, which are thrombin-responsive, were transfected to stably express epitope-tagged receptors for C5a, interleukin-8 (IL-8), formylpeptides (e.g. N-formyl-methionyl-leucyl-phenylalanine (fMLP)), and platelet-activating factor (PAF). Here we demonstrate that both thrombin and a synthetic peptide ligand for the thrombin receptor (sequence SFLLRN) caused phosphorylation and heterologous desensitization of the receptors for C5a, IL-8, and PAF but not that for formylpeptides as measured by agonist-stimulated [35S]guanosine 5'-3-O-(thio)triphosphate binding to membranes. Consistent with the PAF receptor phosphorylation, both thrombin and thrombin receptor peptide inhibited phosphoinositide hydrolysis, Ca2+ mobilization, and degranulation stimulated by PAF. Unexpectedly, despite heterologous desensitization at the level of receptor/G protein activation, there was enhancement ("priming") by thrombin of subsequent activities stimulated by C5a and IL-8 as well as fMLP. The priming effect of thrombin was blocked by its inhibitor, hirudin. However, two other activators of the thrombin receptor, the peptide SFLLRN and trypsin, stimulated Ca2+ mobilization in RBL-2H3 cells but did not cause priming. In addition, SFLLRN and the thrombin receptor antagonist peptide FLLRN both inhibited thrombin-induced Ca2+ mobilization but not priming. Furthermore, the proteolytically active gamma-thrombin, which does not stimulate the tethered ligand thrombin receptor and caused little or no Ca2+ mobilization in RBL-2H3 cells, effectively primed the response to fMLP. These data demonstrate that heterologous receptor phosphorylation and attenuation of G protein activation are not, by themselves, sufficient for the inhibition of biological responses mediated by C5a and IL-8. Moreover, thrombin appears to utilize mechanism(s) independent of its tethered ligand receptor to selectively prime phospholipase C-mediated biological responses of the C5a, IL-8, and formylpeptide receptors but not PAF. Because C5a, IL-8, and formylpeptide activate phospholipase Cbeta2, whereas PAF stimulates a different phospholipase C, the striking selectivity of thrombin's priming may be mediated via its ability to enhance receptor-mediated activation of phospholipase Cbeta2.

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Published In

J Biol Chem

DOI

ISSN

0021-9258

Publication Date

February 9, 1996

Volume

271

Issue

6

Start / End Page

3200 / 3206

Location

United States

Related Subject Headings

  • beta-N-Acetylhexosaminidases
  • Tumor Cells, Cultured
  • Transfection
  • Thrombin
  • Sequence Tagged Sites
  • Recombinant Proteins
  • Receptors, Peptide
  • Receptors, Interleukin-8A
  • Receptors, Interleukin
  • Receptors, Immunologic
 

Citation

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Ali, H., Tomhave, E. D., Richardson, R. M., Haribabu, B., & Snyderman, R. (1996). Thrombin primes responsiveness of selective chemoattractant receptors at a site distal to G protein activation. J Biol Chem, 271(6), 3200–3206. https://doi.org/10.1074/jbc.271.6.3200
Ali, H., E. D. Tomhave, R. M. Richardson, B. Haribabu, and R. Snyderman. “Thrombin primes responsiveness of selective chemoattractant receptors at a site distal to G protein activation.J Biol Chem 271, no. 6 (February 9, 1996): 3200–3206. https://doi.org/10.1074/jbc.271.6.3200.
Ali H, Tomhave ED, Richardson RM, Haribabu B, Snyderman R. Thrombin primes responsiveness of selective chemoattractant receptors at a site distal to G protein activation. J Biol Chem. 1996 Feb 9;271(6):3200–6.
Ali, H., et al. “Thrombin primes responsiveness of selective chemoattractant receptors at a site distal to G protein activation.J Biol Chem, vol. 271, no. 6, Feb. 1996, pp. 3200–06. Pubmed, doi:10.1074/jbc.271.6.3200.
Ali H, Tomhave ED, Richardson RM, Haribabu B, Snyderman R. Thrombin primes responsiveness of selective chemoattractant receptors at a site distal to G protein activation. J Biol Chem. 1996 Feb 9;271(6):3200–3206.

Published In

J Biol Chem

DOI

ISSN

0021-9258

Publication Date

February 9, 1996

Volume

271

Issue

6

Start / End Page

3200 / 3206

Location

United States

Related Subject Headings

  • beta-N-Acetylhexosaminidases
  • Tumor Cells, Cultured
  • Transfection
  • Thrombin
  • Sequence Tagged Sites
  • Recombinant Proteins
  • Receptors, Peptide
  • Receptors, Interleukin-8A
  • Receptors, Interleukin
  • Receptors, Immunologic