Homologous Desensitisation of the Mouse Leukotriene B4 Receptor Involves Protein Kinase C-Mediated Phosphorylation of Serine 127

Jens Mollerup, Heidi N. Eriksen, Janni Albertsen, Tune Wulff, Ian H. Lambert, Else K. Hoffmann

Research output: Contribution to journalJournal articlepeer-review

Abstract

Murine leukotriene B4 (LTB4) receptor (mBLT1) cDNA was identified by searching the EST database using human LTB4 receptor as the query sequence. Expression of functional mBLT1 after injection of in vitro transcribed cRNA into Xenopus laevis oocytes was demonstrated as LTB4-evoked, Ca2+-activated Cl- currents recorded by two-electrode voltage clamp. From mBLT1-expressing oocytes, a dose-dependent relationship between the Ca2+-activated Cl- current and LTB4 concentration was demonstrated with an apparent EC50 of 6.7 nM. Following LTB4 stimulation of mBLT1, we observed two transient, spatially distinct Ca2+-activated, inwardly directed Cl- currents in the oocytes: a fast peak current requiring relatively high LTB4 concentrations, and a slowly progressing Cl- current. Nucleotides, PGE2, 12R-hydroxy-5, 8, 14-cis-10-trans-eicosatetraenoic acid, and LTD4 did not activate mBLT1. U75302, specifically targeting BLT1, significantly reduced LTB4-evoked Cl- currents. Repetitive LTB4 administration desensitized the LTB4-evoked currents. Activation of protein kinase C (PKC) by PMA addition completely eliminated the LTB4-evoked currents, whereas down-regulation of PKC by prolonged PMA exposure (20 h) impaired mBLT1 desensitisation. In addition, Ser-127-Ala substitution of the PKC consensus phosphorylation site on the second intracellular loop prevented the mBLT1 desensitisation. These data indicate that PKC-mediated phosphorylation at Ser-127 leads to mBLT1 desensitisation.Copyright © 2007 S. Karger AG, Basel
Original languageEnglish
JournalCellular Physiology and Biochemistry
Volume20
Issue number1–4
Pages (from-to)143-156
ISSN1015-8987
DOIs
Publication statusPublished - 2007
Externally publishedYes

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