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 Ca2+ influx is through the store-operated (or Ca2+ release-activated Ca2+) channel by which the process of emptying the intracellular Ca2+ stores results in the activation of Ca2+ channels in the plasma membrane. Using both whole-cell patch-clamp and Ca2+ imaging technique, we describe the electrophysiology mechanism underlying formyl-peptide receptor like 1 (FPRL1) linked to intracellular Ca2+ mobilization. The FPRL1 agonists induced Ca2+ release from the endoplasmic reticulum and subsequently evoked ICRAC-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 Ca2+-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.