HSPA5 and familial dilated cardiomyopathy: In addition, protein kinase D (PKD) is also an important target of ERS involved in cardiac remodeling, and PKD expression was elevated in the DCM rat model and the expression of the ERS chaperone molecule GRP78 was increased, and by correlation analysis, GRP78 was significantly correlated with PKD expression (r = 0.914) (Liu et al., 2015).