Figure 3.

IMD inhibits TG-induced endoplasmic reticulum stress by regulating SERCA activity and [Ca²⁺]_i homeostasis. Cardiomyocytes were treated with 3 µM TG in the presence or absence of 100 nM IMD for 24 h. (A) SERCA activity. (B) Representative western blots and semi-quantification of SERCA2 protein levels. (C and D) [Ca²⁺]_i in cardiomyocytes. The intensity of [Ca²⁺]_i fluorescence was measured using fluo-3AM with a laser scanning confocal microscope. Data were analyzed with student's t-test for two group comparison. Data are presented as the mean ± SD. n=3. *P<0.05 and **P<0.01. IMD, intermedin; SERCA, sarco/endoplasmic reticulum calcium ATPase; [Ca²⁺]_i, intracellular Ca²⁺ concentration; TG, thapsigargin; nmol Pi/mg prot/min, nanomoles of phosphorus ions per milligram of protein per minute.