Thapsigargin decreases the Na+- Ca2Â + exchanger mediated Ca2Â + entry in pig coronary artery smooth muscle

►Inhibiting SER Ca2 + pump with thapsigargin blocks Ca2 + entry through NCX. ►There is an increased proximity between the two proteins when SER Ca2 + is depleted. ►A mechanism for the NCX blockade is proposed based on organellar rearrangements. ►This blockade may protect cells from Ca2 + overload when SERCA is not functional.