Expression of ER protein folding machinery in LPS-stimulated wild-type and ATF6α-deficient B cells. Splenic B cells were isolated from Atf6a+/+ and Atf6a−/− mice and cultured in the presence of LPS for the indicated intervals. Expression of (A) Hspa5, encodes ER chaperone BiP/GRP78, (B) Hsp90b1, encodes ER chaperone GRP94, (C) Dnajb11, encodes ER chaperone co-factor ERdj3 and (D) Ero1lb, encodes ER folding enzyme ERO1-like β was assessed by qRT-PCR. Data are plotted as the level of each target mRNA in LPS-stimulated cells relative to that in freshly isolated, resting cells (set at 1) (mean ± S.D., n = 4).