ITPR1 and infection: STING1, coupled with inositol 1,4,5-trisphosphate receptor type 1 [ITPR1, a calcium release channel of endoplasmic reticulum (ER)] and the ATPase sarcoplasmic/ER Ca2+ transporting 2 (ATP2A2, a calcium uptake pump of ER), mediates cytosolic calcium influx to activate CASP1, CASP11, or CASP8 in macrophages/monocytes in response to different infections (62).