Formyl-peptide receptor like 1: a potent mediator of the Ca2+ release-activated Ca2+ current ICRAC.

In electrically non-excitable cells, one major source of Ca(2+) influx is through the store-operated (or Ca(2+) release-activated Ca(2+)) channel by which the process of emptying the intracellular Ca(2+) stores results in the activation of Ca(2+) channels in the plasma membrane. Using both whole-cell patch-clamp and Ca(2+) imaging technique, we describe the electrophysiology mechanism underlying formyl-peptide receptor like 1 (FPRL1) linked to intracellular Ca(2+) mobilization. The FPRL1 agonists induced Ca(2+) release from the endoplasmic reticulum and subsequently evoked I(CRAC)-like currents displaying fast inactivation in K562 erythroleukemia cells which expresses FPRL1, but had almost no effect in K562 cells treated with FPRL1 RNA-interference and HEK293 cells which showed no FPRL1 expression. The currents were impaired after either complete store depletion by the sarco/endoplasmic reticulum Ca(2+)-ATPase inhibitor thapsigargin, or after inhibition of PLC by U73122. Our results present the first evidence that FPRL1 is a potent mediator in the activation of CRAC channels.