Jaw1/LRMP increases Ca(2+) influx upon GPCR stimulation with heterogeneous effect on the activity of each ITPR subtype

Ca(2+) influx upon G protein-coupled receptor (GPCR) stimulation is observed as a cytosolic Ca(2+) concentration oscillation crucial to initiating downstream responses including cell proliferation, differentiation, and cell–cell communication. Although Jaw1 is known to interact with inositol 1,4,5-triphosphate receptor (ITPRs), Ca(2+) channels on the endoplasmic reticulum, the function of Jaw1 in the Ca(2+) dynamics with physiological stimulation remains unclear. In this study, using inducible Jaw1-expressing HEK293 cells, we showed that Jaw1 increases Ca(2+) influx by GPCR stimulation via changing the Ca(2+) influx oscillation pattern. Furthermore, we showed that Jaw1 increases the Ca(2+) release activity of all ITPR subtypes in a subtly different manner. It is well known that the Ca(2+) influx oscillation pattern varies from cell type to cell type, therefore these findings provide an insight into the relationship between the heterogeneous Ca(2+) dynamics and the specific ITPR and Jaw1 expression patterns.