SIGMAR1 and Huntington disease: Here we analyzed whether PRE084 may influence the mitochondrial [Ca2+] levels, which is based upon the observations that Sig-1R is present in MAM and stabilizes the IP3R1.13 Furthermore, mutant huntingtin can interact with ER6, 9 and modulate calcium signaling in HD.18, 19 Using the mitochondrial calcium reporter aequorin, we show here that neither PRE084 nor expression of mutant huntingtin proteins influenced [Ca2+]mito levels in the PC6.3 cells (Figure 3).